A kit and a method for installing a drainage gutter element above a roof window

Abstract

A kit, and a method for using the kit, for installing a roof window in an inclined roof, the kit comprising a drainage gutter element for draining away water from an aperture in the underroof above the roof window onto an intact part of the underroof, and a holding element for holding a portion of the underroof in the drainage gutter element. The holding element comprises an elongate body with an exterior comprising corrugations is configured to be inserted into the drainage gutter element.

Description

Technical Field

[0001] The present invention relates to a kit for use when installing a roof window in an inclined roof, said kit comprising an elongate drainage gutter element for installation above the roof window and for guiding water away from an aperture in an underroof of the inclined roof, the drainage gutter element defining a longitudinal axis, a height axis and a width axis and comprising a first side and second side, the height axis being perpendicular to the longitudinal axis and the width axis being perpendicular to the longitudinal axis and to the height axis, the first side and second side of the drainage gutter element each extending in the longitudinal axis and in the height axis of the drainage gutter element and being spaced apart in the width axis thereby defining a channel of the drainage gutter element for draining away water along the longitudinal axis, the kit further comprising at least one holding element for retaining part the underroof in the drainage gutter.Background Art

[0002] Installation of a roof window entails the mounting of a number of additional components, such as flashing and insulation components, which are typically supplied alongside the roof window. One such component is a drainage gutter for guiding water away from an aperture in an underroof which aperture is made to make room for the roof window in an inclined roof. The drainage gutter is mounted along the top of the roof window and used to drain off water along the top of the roof window and out onto an intact part of the underroof extending along the side(s) of the roof window.

[0003] Various drainage gutter designs are known, one of which is the telescopic type disclosed in EP1131513B1 where two drainage gutter profiles (elements) are configured to have one slide lengthwise in the other to adapt the length of the drainage gutter to the roof window installation.

[0004] As described in EP1131513B1, installation of the drainage gutter entails a cutting a tongue or flap (used interchangeably) in the underroof above the roof window and inserting the flap in the drainage gutter, where water will then drain from the underroof above the roof window and into the drainage gutter by way of the flap. For flexible underroofs water may gather in any pocket formed above the drainage gutter, which may cause the underroof to sag and potentially dislodge the flap from the drainage gutter and thus compromising water-tightness. Especially during installation, where roof covering, e.g. tiles, is not yet in place, a substantial water load may be present. Hence, a means of retaining the underroof flap in the drainage gutter is needed, which can retain the underroof flap in the drainage gutter for the lifetime of the roof window installation, which may be 20 years or more. EP1131513B1 discloses such a holding element in the form of a U-shaped profile lockingly engaging in the drainage gutter, providing a simple and easy to use holding element which can be inserted and removed to adjust the positioning of the underroof and provides the necessary grip to retain the underroof flap.

[0005] While this known U-profile holding element works well, it is made from a steel or aluminium, which has good properties in terms of manufacturing and functionality, is less desirable in terms of environmental and climate impact. Hence, providing a holding element which allows using material with reduced environmental and climate impact is desirable.

[0006] Still further, improving on the physical ergonomics, user-friendliness, of the holding element is desirable, both to improve working conditions for installers and to minimize potential errors in installation by providing components which are easy to use and handle.Summary of Invention

[0007] With this background, it is therefore an object of the invention to provide an improved means of retaining the underroof in a drainage gutter above a roof window.

[0008] In a first aspect of the invention, this and further objects are achieved with a kit as described in the introduction, characterized in that the at least one holding element comprises an elongate body defining a longitudinal axis, and the elongate body is configured to be inserted into the channel of the drainage gutter element with the longitudinal axis of the holding element extending along the longitudinal axis of the drainage gutter element, and in that an exterior of the elongate body comprises corrugations providing alternating ridges and grooves, which ridges and grooves extend in the longitudinal axis of the holding element.

[0009] The elongate body, such as circular cylinder, of the holding element is easy for the installer to insert into the channel of the drainage gutter element and also easy to grasp and retrieve from the channel for readjustment of e.g. the underroof flap. At the same time, the corrugated exterior with alternating ridges and groves allows the holding element to engage with the channel and underroof flap providing sufficient grip to anchor the underroof flap, but still allow the installer to adjust the position holding element if necessary. The grooves further allow water to drain along the channel of the drainage gutter element passing the holding element, preventing water accumulation in the channel. This holding element can be made from a wide range of materials, and thus allows the use of a material with a lower climate and / or environmental impact, such as plastic, and in particular thermoplastics.

[0010] In a second aspect of the invention there is provided a method for installing a drainage gutter element above a roof window in an inclined roof using the kit. Said method comprises cutting an underroof of the inclined roof above the roof window thereby providing an underroof flap, mounting the elongate drainage gutter element above the roof window at the underroof flap with the channel of the drainage gutter element arranged to drain away water along the longitudinal axis away from an aperture in the underroof, arranging the underroof flap in the channel of the drainage gutter element, inserting at least one holding element into the channel of the drainage gutter element, wherein the longitudinal axis of the holding element extends along the longitudinal axis of the drainage gutter element.

[0011] Thus inserted, the ridges of the holding element engage both the underroof flap and the channel of the drainage gutter element to anchor the underroof flap therein. To anchor the underroof flap along the length of the drainage gutter element, a plurality of holding elements can be inserted in the channel of the drainage gutter element. The holding elements provide sufficient anchoring to allow the plurality of holding elements to be spaced at a distance from each other along the longitudinal axis of the drainage gutter element. In this way, material use can be reduced. The holding elements are preferably arranged with mutual distance of at least 5 or at least 10 cm. A mutual spacing in the range of 10 to 40 cm, or 15 to 35 cm is typically suitable.

[0012] In the following further details and embodiments of the drainage gutter element and the holding element(s) will be described, which details and embodiments apply to both the kit of the first aspect of the invention and to the method of the second aspect of the invention.

[0013] Generally, the kit can comprise a single drainage gutter element, or a drainage gutter element which forms part of a telescopic drainage gutter. Hence, the drainage gutter element mentioned above can be an external drainage gutter element or an internal gutter element of the telescopic drainage gutter. These internal and external drainage gutter elements are configured such that the internal drainage gutter element can slide longitudinally within the channel of the external drainage gutter element. Hence, the external gutter profile may generally have cross-sectional dimensions slightly exceeding the corresponding dimensions of the internal drainage gutter element.

[0014] Retaining or anchoring the underroof flap in the channel of the drainage gutter is achieved by holding element clamping the underroof flap between the channel and the holding element. The anchoring may be improved by a width of the holding element, measured at the exterior of the holding element perpendicularly to the longitudinal axis of the holding element, corresponding to a largest width of the channel of the drainage gutter element, the largest width being measured along the width axis. Hence, in these embodiments at least one cross-sectional dimension of the holding element can engage across the width of the channel. "Corresponding widths" may in this context be the width of the holding element being within 20 % or 10 % of the largest width of the channel of the drainage gutter, as such differences may be accommodated by drainage gutter element and / or holding element being slightly deformable and / or the presence of underroof flap in the installed state. At least to reduce the number of different components, it is preferable that the width of the holding element corresponds to the largest width in the external drainage gutter element, when the kit comprises the telescopic drainage gutter, as this will also be suitable for the internal drainage gutter element.

[0015] To facilitate insertion into and retrieval from the channel it is preferable for the holding element to yield slightly to force. Hence, in some embodiments, a perimeter of the holding element extends in a cross-section perpendicular to the longitudinal axis of the holding element, and the elongate body comprises at least two ridged portions extending along the perimeter, the ridged portions comprising the ridges and being spaced apart along the perimeter by intermediate portions of the elongate body. The intermediate portions provide pre-defined zones of the holding element which preferentially yields to force compared to the ridged portions. In some embodiments, the intermediate portions are made from a material which is more elastic than the material forming the ridged portions, providing said pre-defined zones. In other, more preferred embodiments the intermediate portions have a reduced thickness compared to a thickness of the ridged portions. This provides a simple way to provide the pre-defined zones, where a single material can be used for the holding element, simplifying manufacturing. Additionally, the intermediate portions may have uniform thickness. The thickness of the ridged portions and intermediate portions are measured normal to the exterior of the holding element. The thickness of the ridged portion is measured at an apex of the ridges.

[0016] The at least two intermediate portions may be positioned at opposite sides of the holding element and similarly the at least two ridged portions may be positioned at opposite sides of the holding element.

[0017] It is preferred that each of the intermediate portions constitute less of the perimeter than the ridged portions, i.e. that the ridged portions forms a greater portion of the exterior surface of the holding element than the intermediate portions. Hence, the ridged portions may each form more than 25 % of the perimeter, and / or may collectively form more 50 % of the perimeter. The proportion of the perimeter formed by a ridged or intermediate portion is determined without accounting for the increased surface provided by the corrugations. This may be determined by projecting the respective portions onto a circle which encompasses the cross-section the holding element and comparing the relative size of the projections.

[0018] In alternative embodiments, the corrugations extend continuously along the perimeter of the elongate body, i.e. the entire perimeter as seen in a cross-section across the longitudinal axis of the holding element. Hence, the entire exterior surface of elongate body comprises alternating ridges and grooves.

[0019] As mentioned, the geometry of the holding element allows a wide range of material options. The holding element can thus be made of a metal such as a steel or aluminium, which will provide a holding element with good anchoring and keep its properties in the lifetime of the installation, but selecting a material which may be more advantageous in terms of climate / environmental impact, while maintain good anchoring performance, is desirable. This may be achieved by at least part of the holding element, preferably the entire holding element, being made from a thermoplastic polymer. These materials can offer a rigidity which leads to strong anchoring of the underroof flap in the installed state while in certain geometries providing some flexibility providing slight deformation during the installation. Thermoplastic polymers generally exhibit an amount of creep (cold flow) where stress in the material reduced with time when subjected to consistent load. This may be advantageous as the strength of the holding element may lessen during the installation lifetime, which may be 20 years or more, and the reduced stress may reduce the risk of the holding element fracturing with time. The thermoplastic polymer may be selected from ABS, HDPE, POM, PA6 or PP. PP (polypropylene) is preferred as it is widely available and cost-effective. To improve the environmental and / or climate impact of the holding element, using a recycled thermoplastic polymer for at least a part and preferably the entire holding element is preferred. Recycled polypropylene is preferred.

[0020] Using a thermoplastic material for the holding element also allows the holding element to be produced by injection moulding which is preferred method. Other production methods such as extrusion or blow moulding may be considered. These methods also provide the holding element as in integrally formed element, although integrally formed holding elements can be provided by other production methods, such as additive manufacturing. An integrally formed holding element of single material is preferred to reduce cost and may be achieved with the mentioned thermoplastics, including polypropylene.

[0021] The holding elements can alternatively be made as from two (or more) materials, e.g. corrugations formed of one more material provided on a core of a more rigid material, such as corrugations of a thermoplastic and optionally elastomeric material provided on a core body of a more rigid material, such as polypropylene or a metal such as steel or aluminium. Such an embodiment may provide increased friction to the drainage gutter and the underroof flap and thus improved anchoring. Similar advantages could be achieved by an anti-slip coating on the ridges of the holding element. However, the increased friction has not been necessary in practice with typical drainage gutter element geometries but could be advantageous in less common geometries. The ridges of the holding element which extend in the longitudinal axis of the holding element define a space between the ridges, referred to as grooves, which allow water to drain away when the holding element is arranged in the channel of the drainage gutter element. The ridges also provide a means for the holding element to engage any protruding parts of the drainage gutter. This may be achieved by holding elements wherein a thickness of the ridges is 0.5 to 4 mm, preferably 0.7 to 3 mm and more preferably 1 to 2 mm. The thickness of a ridge may be measured normal to an apex of the ridge, from said apex to a base of the ridge. The base of the ridge is a level of a groove between the ridge measured at an adjacent ridge.

[0022] The ridges are projecting portions of the exterior of the elongate body and the ridges may have many cross-sectional shapes, but it is presently preferred for the exterior of the elongate body to comprise corrugations which provide the ridges and intervening grooves with a curved shape. This corrugated shape, or wave shape, has been observed to provide good anchoring of the underroof flap in drainage gutter channels of different cross-sections, where angular ridges may have little contact to the underroof flap and are thus less preferred.

[0023] In general, it is desirable to provide relatively wide ridges to provide good anchoring. A narrow ridge may be prone to deformation or fracturing depending on the material choice, which is detrimental to the anchoring function. Hence, it is desirable for the ridges to have an aspect ratio above 1, expressed as the ratio between a width of the ridge and the thickness of the ridge. The width of the ridge extends perimetrically as a distance between the bases at either side of the ridge. The number of ridges may be within the range of 10 to 40.

[0024] The ridges may generally be uniform in size and shape. They may further be uniformly spaced along the perimeter. In the embodiments, where the holding element has intermediate portions spacing apart some the ridges, then the ridges within the ridged portions may be uniformly spaced.

[0025] To further improve drainage of water, the elongate body of the holding element may be hollow and open at its longitudinal ends. In this way water can also drain through the holding element, which may serve to reduce the risk of water temporarily accumulating at an upstream end of the holding element. Such water accumulation may not be an issue throughout the lifetime of the roof window installation, but before installation and during replacement of roof covering, increased water load on the underroof can occur. The hollow elongate body works well in combination with intermediate portions of reduced thickness to provide the flexibility as previously described, but a hollow elongate body also provides flexibility to embodiments having corrugations extending continuously along the perimeter.

[0026] As previously mentioned it is preferable for the holding element to have pre-defined zones which yield slightly when the holding element is inserted or retrieved for the channel of the drainage gutter, but the return substantially to the original geometry. If the holding element does not keep it shape, this could be detrimental to its anchoring function. Hence at least in part of the holding element, solid material extends continuously along the perimeter in the cross-section. Hence, a cross-section of the elongate body perpendicular to the longitudinal axis of the holding element is a closed shape. The term closed shape is here used to mean that the cross-sectional profile of the elongate body forms a continuous enclosed shape. It is preferable that at least 50 % of a total length of the elongate body constitutes a closed shape as seen in the cross-section perpendicular to the longitudinal axis of the holding element, and more preferably that the entire length of the elongate body constitutes such an enclosed shape. The elongate body may for example be provided with openings into a hollow space of the elongate body which openings are arranged discretely in sequence along the longitudinal axis of the holding element. Such openings may be provided to increase drainage across the cross-section and / or to reduce material use. A reduction in material use may also be achieved by one or more ridges comprising a plurality of ridge portions spaced apart in the longitudinal axis of the holding element, collectively forming the respective ridges. However, each ridge is preferably a continuous ridge extending along the length of the elongate body, preferably substantially along the entire length.

[0027] The holding element is configured to be inserted into the channel and thus has a cross-sectional shape which fits into the channel of the drainage gutter. In some embodiment, a cross-section of the elongate body forms a shape selected from: circular, oval, rectangular, pentagonal, hexagonal, or higher order polygonal. Higher order polygonal refers to heptagons, octagons etc. An elongate body with a circular cross-sections is presently preferred owing to its strength, its versatility in terms fitting into differently shaped drainage gutters, and that it will generally not be necessary for the installer to arrange it in specific manner before when inserted, making the installation easier. Pentagons, hexagons, heptagons etc. may offer some similar advantages but may be more prone to fracturing at the corners than a circle.

[0028] Drainage gutter elements may often comprise parts which extend along the length of the gutter element and project into the channel, such as guiding tracks for the telescopic sliding of an internal gutter element in an external gutter profile, and / or hemming along the edges of sheet metal drainage gutters. These may be used to improve the anchoring of the holding element in the channel of the drainage gutter. Hence, in some embodiments an upper end of the second side of the drainage gutter element comprises an inwardly projecting portion extending in the width axis, and a width of the holding element measured at the exterior of the holding element perpendicularly to the longitudinal axis of the holding element, is less than a transverse distance measured from the inwardly projecting portion to the first side of the drainage gutter element along the width axis. The drainage gutter element and / or the holding element may yield slightly when inserting the holding element, allowing the element to pass across the transverse distance, but inwardly projecting portion may then contribute to anchoring once inserted.

[0029] Additionally or alternatively, the width of the holding element may be configured to engage the inwardly projecting portion to further improve anchoring.

[0030] As described the holding elements are to be spaced apart in along the length of the drainage gutter element when in use, providing discrete points of anchoring along the top of the roof window installation. The kit may thus comprise a plurality of holding elements, with one holding element per 20 to 40 cm of drainage gutter length typically being suitable. Typically, the drainage gutter will be longer than a width of the roof window installation, hence providing for example one holding element per 30 cm of drainage gutter length, may allow a mutual spacing of the holding elements of e.g. 15 to 25 cm.

[0031] The holding elements are a relatively short component in relation to the length of the drainage gutter element. Hence, the total length of the holding element is less than a total length of the drainage gutter element, preferably 30 % or less, more preferably 25 % or less, more preferably 20 % or less, and more preferably 10 % or less. Additionally or alternatively the total length of the holding element is 15 cm or less, preferably 10 cm or less, more preferably 3 to 7 cm. Similarly, in the kit comprising plurality of holding elements per drainage gutter element, a collective length of the plurality of holding elements is less than a total length of the drainage gutter element, preferably 50 % or less, more preferably 40 % or less, more preferably 30 % or less.

[0032] The kit may be supplied alongside other components used when installing the roof window, often packed together with components used at the same stage in the installation.

[0033] A packed roof window product may thus comprise the kit and one or more roof window product components packed in a cardboard box, where the kit comprises the drainage gutter element and the at least one holding element, and the one or more roof window product components are selected from: an underroof collar, an insulation frame for surrounding a frame of the roof window, a vapour barrier membrane or collar, and cladding and covering component.

[0034] Other presently preferred embodiments and further advantages will be apparent from the subsequent detailed description and drawings.Brief Description of Drawings

[0035] In the following description, embodiments of the invention will be described with reference to the schematic drawings, in which Fig. 1 shows a roof window installation in an inclined roof where a telescopic drainage gutter is being installed above an aperture in an underroof, Fig. 2 shows a cross-sectional view of a kit with a holding element in a channel of a drainage gutter element in an installed state, Figs. 3 and 4 show an embodiment of the holding element with ridges throughout a perimeter of the holding element in perspective view and longitudinal view respectively, Figs. 5 and 6 show an embodiment of a holding element with intermediate portions spacing apart ridged portions of the holding element in perspective view and cross-sectional view respectively, and Figs. 7a-b shows cross-sectional view of an external drainage gutter element and an internal drainage gutter element, respectively, in an embodiment of the kit comprising a telescopic drainage gutter. Description of Embodiments

[0036] Referring initially to Fig. 1, two roof windows 4 are shown side-by-side in an inclined roof 5. The inclined roof 5 may comprise any kind of subjacent roof structure of a building located towards an interior, here schematically indicated as including rafters extending in the inclination of the roof and battens positioned transversely to the rafters. The roof windows 4 may comprise roof penetrating structures of any type.

[0037] It is noted that terms such as "up", "down", "left-hand", "right-hand", "exterior", "interior", "outer", "inner" etc. are relative and refers to the viewpoint in question. In general, when referring to an exterior side, this relates to a side of a roof window in the mounted condition facing the outdoors or external side of the building.

[0038] In the present context, terms such as "above" and "below" generally designate positions of an element relative to the roof window 4 in the direction of inclination of the roof 5, unless otherwise specified.

[0039] Two elongate drainage gutter elements 2, 3 are shown located above the two roof windows 4 in the process of being mounted in the inclined roof 5 using a kit for roof window installation. In this embodiment, the kit comprises two drainage gutter elements 2, 3 which collectively form a telescopic drainage gutter, where the drainage gutter element 3 shown to the left is an internal drainage gutter element 3 which can slide lengthwise into an external drainage gutter element 2 shown on the right. It is preferred to use telescopic drainage gutters in the kit as a single size telescopic drainage gutter can be adjusted for a wide range of roof window installation sizes. In Fig. 1 the drainage gutter elements 2, 3 are in an extended position where they span the width of the two roof windows 4. However, the invention is equally applicable to kits comprising only one drainage gutter element of a length corresponding to the width of the roof window(s) 4 of the roof window installation, or more than two drainage gutter elements that may be extended to cover an even wider range of roof window installation sizes.

[0040] An underroof membrane 51 is installed in the inclined roof 5 on top of the subjacent roof structure and an aperture 50 is made in which the roof windows 4 are installed. The purpose of the drainage gutter elements 2, 3 is to guide any water coming down from above the roof windows 4 away from the roof windows 4 and the aperture 50 in the underroof 51. To ensure that water coming down enters the drainage gutter elements 2, 3 a cut 511 is made in the underroof 51 to provide an underroof flap 512 which can then be arranged in drainage gutter elements 2, 3. In this way, water will instead drain into to the drainage gutter elements 2,3 by way of the part of the underroof extending into the drainage gutter elements, i.e. the underroof flap 512. The drainage gutter elements 2, 3 define a longitudinal axis L along which water drains.

[0041] Further details of the drainage gutter elements 2, 3 are shown in Figs. 7a-b showing respectively a cross-section of the internal drainage gutter element 3 and the external drainage gutter element 2 of Fig. 1 across the longitudinal axis L. The two drainage gutter elements further define a height axis H and a width axis W which are mutually perpendicular and perpendicular to longitudinal axis L. Referring jointly to the respective drainage gutter element 2, 3 of the shown embodiment, each of the drainage gutter elements 2, 3 comprises a first side 21, 31 and a second side 22, 32 which each extends along the longitudinal axis L and the height axis H of the drainage gutter element 2, 3. The first side 21, 31 and the second side 22, 32 of each drainage gutter element 2, 3 are spaced apart in the width axis W thereby defining between them a channel 20, 30 of the drainage gutter element 2, 3. The channel 20, 30 is for draining water along the longitudinal axis L out onto the intact part of the underroof 51. In the embodiment shown, the first side 21, 31 and second side 22, 32 form legs which extend in parallel to the height axis H with a bottom 23 connecting the two sides 21, 22; 31, 32 providing the shown rectangular cross-section of the channel 20, 30. Alternative shapes are possible, e.g. the first side 21, 31 and second side 21, 31 could alternatively extend at angle to the height axis, providing a trapezoid-shaped channel, or the first side 21, 31 and second side 22, 32 being curved, to provide a curved U-shape or circular cross-section of the channel 20, 30. Drainage gutter elements with these and further alternative shapes, such as, hexagonal, octagonal, or other polygons, can be used in the kit according to the invention. The drainage gutter elements 2, 3 are made of steel shaped by roll-forming, but other metals, such as aluminium, and shaping methods can be used for drainage gutter elements. The first side 21, 31 extends further in the height axis H than the second side 22, 32 and is the side intended to lie against the subjacent roof structure of the roof 5 through which nails or screws are attached to fasten it to the subjacent roof structure of the roof 5. The second side 22, 32 is shorter than the first side 21, 31 as measured along the height axis H. An upper end of the second side 22, 32 of each of the drainage gutter elements 2, 3, i.e. the portion furthest from the bottom 23, 33 along the height axis H, comprise an inwardly projecting portion 220, 320 projecting inwardly into the channel along the width axis W. In this embodiment, the inwardly projecting portions 220, 320 guide the telescopic connection between the two drainage gutter elements 2, 3 by the inwardly projecting portion 220, entering the inwardly projecting portion 320. The first side 21, 31 of each of the drainage gutter elements 2, 3 also have corresponding inwardly portions 210, 310 serving the same function.

[0042] Turning back to Fig. 1 which further shows a plurality of holding elements 1 provided as part of the kit along with the drainage gutter elements 2, 3. Once the installer has mounted the drainage gutter elements 2, 3 to the subjacent roof structure of the roof 5, the underroof flap 512, made by the cut 511, is then arranged inside the drainage gutter 2, 3 passing down the first side 21, 31 and extending into the channel 20, 30, as is shown in Fig. 2. To keep the underroof flap 512 inside the drainage gutter elements 2, 3, the holding elements 1 are inserted into drainage gutter elements 2, 3 to anchor the flap 511 in the drainage gutter element 2,3 to prevent it from dislodging, which could otherwise risk causing damage to the roof or window as water could then drain past the drainage gutter elements 2, 3.

[0043] In Fig. 1, there are five holding elements 1 but this is illustrative as there could be fewer or more holding elements depending on the width of the roof window(s) of the installation in question. The five holding elements 1 are placed along the drainage gutter elements 2, 3 at a distance from each other. The longitudinal distance between the holding elements 1 is here around 25 cm. A short mutual spacing is not desirable as it increases material use, but a mutual spacing of 10-40 cm is generally suitable. The holding elements 1 are short compared to the drainage gutter elements 2, 3, where a length L3 of the internal drainage gutter element 3 is indicated in Fig. 1. In this embodiment each of the holding elements 1 has a length of about 5 cm corresponding to about 5 % of the length L3 of the drainage gutter elements 2, 3 and about 2 % of the fully extended length of the telescopic drainage gutter. The collective lengths of the holding elements 1 will be less than the length of each drainage gutter element 2, 3 and also less than the collective length of the drainage gutter in the installed state, typically less than 50 % thereof.

[0044] Turning now to Fig. 2, which shows a cross-section of one holding element 1 mounted in the external drainage gutter element 2. As can be seen, a width W1 of the holding element 1 corresponds to a width W20 (shown in Fig.7a) of the channel 20. The holding element 1 therefore provides engagement to both the first side 21, 31, the second side 22, and thus clamps the flap 512 in the drainage gutter 2. In addition to the underroof flap 512, part of an underroof collar 40 mounted around the roof window (not shown) is also inserted into the channel 20 of the drainage gutter 2. The part of the underroof collar 40 and the underroof flap 512 are layered in the channel 20, with the underroof collar 40 immediately adjacent to the drainage gutter element 2 and the underroof flap 512 layered on top. The holding element 1 here has a circular cross-section and the width W1 is the diameter measured at an exterior 16 of the holding element 1 perpendicularly to the longitudinal axis of the holding element 1. For alternative shapes, where the width of the holding element 1 may not be uniform, at least one width W1 of the holding element should correspond to the width W20 of the channel 20 to achieve the same. The width W20 of the channel 20 may also be irregular, in which case the width W1 may correspond to a largest width W20 of the channel 20, e.g. the diameter of a circular channel 20 (not shown). This embodiment of the holding element 1 is integrally formed from one material by injection moulding and an injection moulding aid 17 is visible as an edge in Fig. 2. It is common in injection moulding to include such moulding aids, such as of angled surfaces and off-sets, to facilitate retention and release of the moulded element from the tool. In this embodiment, the holding element 1 also fits tightly below the inwards projecting portion 220 of the second side 22, i.e. here by the width W1 (being the uniform diameter) corresponding to the a distance between the bottom 20 and the inward projecting portion along the height axis H such that the holding element engages the inwardly projecting portion 220. The holding elements 1 thus engages the inwards projecting portion 220, here with the underroof collar 40 in between, from below to further improve anchoring of the holding element 1. The exterior 16 of the holding element 1 comprises ridges 12 and grooves 13, which will be described in greater detail below, which improve this engagement to the inwards projecting portion 220. As can be seen the width W1 is also greater than a transverse distance W21 between the inwards projecting portion 220 and the first side 21 along the width axis W1, whereby the holding element 1 is further locked in place in the channel 20. The drainage gutter element 2 is sufficiently flexible to insert and retrieve the holding element 1 from the channel 20 through the width W21. Although Fig. 2 shows the drainage gutter 2, the cross-section is similar at the drainage gutter 3 in Fig. 1, with similar relationships between the width W1 and a width W30 of the channel 30 and transverse distance W31 at the inwardly projecting portion 320 (see Fig. 7b).

[0045] Further details of the holding element 1 will now be described with reference to the embodiment shown in Figs. 3 and 4, showing a perspective view and a cross-sectional view of the holding element 1 of Fig. 2. The holding element 1 has an elongate body 10 defining a longitudinal axis C and extends a length L1, which is here about 5 cm. When the holding element 1 is inserted into the channel 20, 30 of the drainage gutter element 2, 3 its longitudinal axis C extends along the longitudinal axis L of the drainage gutter element (see Fig 1). An overall cross-sectional shape of the elongate body 10, when disregarding the ridges 12 and grooves 13, is circular and the elongate body 10 thus forms a hollow circular cylinder. This shape is preferred for its strength and ability to function in several different gutter geometries, e.g. in rectangular cross-sections as in Fig. 2, but equally well in circular, hexagonal or similarly shaped gutters (not shown). The elongate body 10 is hollow and open at its longitudinal ends. This allows water to drain through the holding element 1 in the installed state. A hollow elongate body 10 with a relatively thin thickness D3, from the exterior surface to an interior surface of the elongate body, may also allow it to deform slightly which helps when inserting it into the channel 20 of the drainage gutter and passing the transverse distance W20 at the inwardly protruding portion 220 if present (see Fig 2). Once inside the channel the holding element 1 seeks to recover its original form, which aid the anchoring function. This is the case for the holding element in Figs. 3 and 4 which made from a polypropylene, but other thermoplastics are also suitable. An injection moulding aid 17 in the form of a step is visible within the elongate body 10 in Fig. 3 and also as a edge in the view of Fig. 4.

[0046] As can be seen the cross-section of the elongate body 10 is a closed shape, in the sense that the material is continuous along the entire perimeter (circumference) in a cross-section perpendicular to the longitudinal axis C. This makes the holding element 1 rigid, allowing it to clamp and keep the underroof flap 512 in the channel 20, without collapsing. Openings can be provided in the elongate body (not shown), but at least in part of the holding element, the cross-section should be a closed shape to provide rigidity. The bulky overall geometry of the elongate body 10 is easy to grasp for the installer and in particular is easy to grasp from its installed state in the channel of the drainage gutters.

[0047] The exterior 16 of the elongate body 10 has corrugations 11 along the entire perimeter, therefore providing grooves 13 and ridges 12 around its surface, which in this embodiment is about 20 ridges. The ridges 12 and grooves 13 each extends along the longitudinal axis C of the holding element 1, and in this embodiment, along the entire length of L1 of the holding element 1 and in parallel with the longitudinal axis C, as shown in Fig. 3. The corrugated or wave-shape of the exterior 16 of the holding element 1, as well as the open longitudinal ends of the grooves 13, allows water to drain along the holding element 1. The ridges 12 are seen to have a curved shape providing a curved apex. This shape provides good engagement to the channel of the drainage gutter, and the alternation of grooves and ridges provide anchoring to any projecting portions there of as in Fig. 2. The ridges 12 have a thickness D1 which may be measured as the distance between a bottom of the grooves 13 and an apex of the ridges 12 measured normal to the apex of the ridges 12. Here D1 is about 1.2 mm, but it may generally be in an interval of 0.5 to 4 mm. In Fig. 4 D1 is indicated as the distance between a circle passing the apex of the ridges 12 and a circle passing the bottom of the grooves 13. D1 is about half an overall thickness D3 of the elongate body 10, which in this case is about 3mm (measured at the ridges 12 from the exterior to the interior of the holding element 1). As mentioned, the small thickness D3 provides some flexibility reduces material use. A thickness D3 which is about 1 to 4 times D1 is generally suitable. The ridges 12 are seen to be relatively wide in relation to their thickness D1, where a width A1 of the ridge 12 here is about twice the thickness D1. Very thin ridges may be prone to deformation or fracture, which may be detrimental to the anchoring function. The width A1 of a ridge 12 is the distance between the bottom of the grooves 13 adjacent to the ridge 12 in question as shown in Fig. 4.

[0048] Turning now to the further embodiment of the holding element 1 shown Figs. 5 and 6, in views corresponding to those in Figs. 3 and 4. Similar or identical features in the embodiments of Figs 3-4 and Figs. 5-6 will not be described again and share the same reference numeral. This embodiment is similar to the one in Figs 3-4, but instead of the ridges 12 extending along the entire perimeter of the elongate body 10, the elongated body 10 has two ridged portions 14 separated by intermediate portions 15. The two ridged portions 14 each extend along the longitudinal axis C and are spaced apart along the perimeter by the intermediate portions 15 which also extend along the longitudinal axis C. The intermediate portions 15 provide predefined zones which provide more flexibility to the holding element 1. The intermediate portions 15 have a lower thickness D2 compared to the thickness of ridged portions D3 making them more flexible, which facilitates inserting and retrieving the holding element from the drainage gutter. Here the ridged portions 14 and intermediate portions 15 are made from the same material, which is preferable for production purposes, but in other embodiments, the intermediate portions could made from a material which is more elastic than the material forming the ridged portions. The holding element is formed by injection moulding, and hence the circular line appearing to separate the ridges 12 from the remainder of the elongate body 10 is not to be construed as an indication that these are two components attached together. The thickness D3 of the ridged portions 14 is measured from the interior of the hollow holding element 1 to the exterior of the holding element, here the apex of the ridges 12 in a direction normal to the apex. Similarly, thickness D2 of the intermediate portion 15 is defined is the distance between the interior and exterior 16 of the holding element 1, measured normal thereto.

[0049] The intermediate portions 15 form a lesser part of the elongate body 15 compared to the ridged portions 14. Here, each intermediate portions 15 is about 10 % of the total cross-sectional perimeter of the elongate body 10, disregarding the contribution of the ridges 12 to the perimeter. This is evaluated by the proportion formed by a projection of the intermediate portions 14 onto a circle passing through all the ridges 12.

[0050] The components of the kit of the present invention may advantageously be sourced and produced sustainably. Since the holding elements of the kit are held by mechanical means only, dismounting of the roof window installation including the kit for refurbishing or at the end of life allows the components of the kit to be removed without disintegration for repurposing or recycling in an environmentally sustainable manner.List of reference numerals

[0051] 1Holding element 10Elongate body 11Corrugation 12Ridge 13Groove 15Intermediate portion 16Exterior of holding element 17Moulding aid W1Width of holding element L1Length of holding element D1Thickness of the ridge D2Thickness of intermediate portion D3Thickness of the ridged portion 2, 3Drainage gutter element 20,30Channel 21, 31First side of drainage gutter element 210, 310Inwardly projecting part of first side 22, 32Second side of drainage gutter element 220, 320Inwardly projecting portion of second side 23, 33Bottom W20, W30Width of channel W21, W31Distance between inwardly projecting portion and first side 4Roof window 40Underroof collar 5Inclined roof 50Aperture for roof window 51Underroof 511Cut in underroof 512Underroof flap CLongitudinal axis of holding element LLongitudinal axis of drainage gutter element WWidth axis of drainage gutter element HHeight axis of drainage gutter element

Claims

1. A kit for use when installing a roof window (4) in an inclined roof (5), said kit comprising an elongate drainage gutter element (2, 3) for installation above the roof window (4) and for guiding water away from an aperture in an underroof (52) of the inclined roof, the drainage gutter element (2, 3) defining a longitudinal axis (L), a height axis (H) and a width axis (W) and comprising a first side (21, 31) and a second side (22, 32), the height axis (H) being perpendicular to the longitudinal axis and the width axis (W) being perpendicular to the longitudinal axis and to the height axis, the first side (21, 31) and second side (22, 32) of the drainage gutter element each extending in the longitudinal axis (L) and in the height axis (H) of the drainage gutter element and being spaced apart in the width axis (W) thereby defining a channel (20, 30) of the drainage gutter element for draining away water along the longitudinal axis, the kit further comprising at least one holding element (1) for retaining part (512) the underroof (52) in the drainage gutter, characterized in that the at least one holding element (1) comprises an elongate body (10) defining a longitudinal axis (C) of the holding element, and the elongate body (10) is configured to be inserted into the channel (20, 30) of the drainage gutter element (2, 3) with the longitudinal axis (C) of the holding element extending along the longitudinal axis (L) of the drainage gutter element (2, 3), and in that an exterior (16) of the elongate body (10) comprises corrugations providing alternating ridges (12) and grooves (13), which ridges (12) and grooves (13) extend in the longitudinal axis (C) of the holding element.

2. The kit according to claim 1, wherein a width (W1) of the holding element, measured at the exterior (16) of the holding element perpendicularly to the longitudinal axis (C) of the holding element, corresponds to a largest width (W2, W3) of the channel (20, 30) of the drainage gutter element (2, 3), the largest width being measured along the width axis (W).

3. The kit according to any one of the preceding claims, wherein a perimeter of the holding element extends in a cross-section perpendicular to the longitudinal axis (C) of the holding element, and the elongate body (10) comprises at least two ridged portions (14) comprising ridges, which ridged portions extending along the perimeter and are spaced apart along the perimeter by intermediate portions (15) of the elongate body.

4. The kit according to claim 3, wherein each of the intermediate portions (15) has a reduced thickness compared to a thickness of the ridged portions, preferably wherein each of the intermediate portions (15) preferably has a uniform thickness.

5. The kit according to any one of the preceding claims, wherein at least part of the holding element (1), preferably the entire holding element (1), is made from a thermoplastic polymer, optionally wherein the thermoplastic polymer comprises recycled thermoplastic polymer, and preferably wherein the thermoplastic polymer is polypropylene and optionally comprises recycled polypropylene.

6. The kit according to any one of the preceding claims, wherein a thickness (D1) of the ridges is 0.5 to 4 mm, preferably 0.7 to 3 mm and more preferably 1 to 2 mm.

7. The kit according to any one of the preceding claims, wherein the elongate body (10) is hollow and open at its longitudinal ends.

8. The kit according to any one of the preceding claims, wherein a cross-section of the elongate body (10) perpendicular to the longitudinal axis (C) of the holding element is a closed shape.

9. The kit according to any one of the preceding claims, wherein the elongate body (10) is cylindrical.

10. The kit according to any one of the preceding claims, wherein an upper end of the second side (22, 32) of the drainage gutter element (2,3) comprises an inwardly projecting portion (220, 320) extending in the width axis, and a width (W1) of the holding element (1) measured at the exterior (16) of the holding element perpendicularly to the longitudinal axis (C) of the holding element, is less than a transverse distance (W21, W31) measured from the inwardly projecting portion (220, 320) to the first side (21, 31) of the drainage gutter element (2, 3) along the width axis.

11. The kit according to any one of claims 1 and 2 and 5 to 10, wherein the corrugations (11) extend continuously along an entirety of a perimeter of the elongate body.

12. The kit according to any one of the preceding claims, wherein a total length (L1) of the holding element (1) is less than a total length of the drainage gutter element (L2) , preferably 30 % or less, more preferably 25 % or less, more preferably 20 % or less, and more preferably 10 % or less, and / or optionally wherein a total length (L1) of the holding element (1) is 15 cm or less, preferably 10 cm or less, more preferably 3 to 7 cm.

13. The kit according to any one of the preceding claims, comprising a plurality of holding elements (1) per drainage gutter element (2, 3), optionally one holding element (1) per 10 to 40 cm of length of drainage gutter element.

14. A method for installing a drainage gutter element (2, 3) above a roof window (4) in an inclined roof (5), said method comprising - cutting an underroof (52) of the inclined roof above the roof window (4) thereby providing an underroof flap (512), - mounting an elongate drainage gutter element (2, 3) above the roof window at the underroof flap (52), wherein the drainage gutter element defines a longitudinal axis (L), a height axis (H) and a width axis (W) and comprises a first side (21, 31) and a second side (22, 32), the height axis (H) being perpendicular to the longitudinal axis (L) and the width axis (W) being perpendicular to the longitudinal axis and the height axis, the first and second side of the drainage gutter element each extending along the longitudinal axis (L) and in the height axis (H) of the drainage gutter element and being spaced apart in the width axis thereby defining a channel (20, 30) of the drainage gutter element, which channel (20, 30) is arranged to drain away water along the longitudinal axis away from an aperture (520) in the underroof, - arranging the underroof flap (512) in the channel (20, 30) of the drainage gutter element, - inserting at least one holding element (1) into the channel of the drainage gutter element (2, 3), characterized in that the at least one holding element (1) comprises an elongate body (10) defining a longitudinal axis (C) of the holding element (1) and extends in the channel (20, 30) of the drainage gutter element with the longitudinal axis (C) of the holding element extending along the longitudinal axis (L) of the drainage gutter element, and in that an exterior (16) of the elongate body (10) comprises corrugations providing alternating ridges (12) and grooves (13), which ridges (12) and grooves (13) extend in the longitudinal axis (C) of the holding element.

15. A method according to claim 14, further comprising inserting a plurality of holding elements (1) in the channel (20, 30) of the drainage gutter element, wherein the plurality of holding elements (1) are spaced at a distance from each other along the longitudinal axis (L) of the drainage gutter element (2, 3), preferably with a mutual distance of at least 5 or 10 cm.

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