Raised flooring apparatus

Abstract

Height adjustable loft stilts provide a raised floor surface. The apparatus comprises a base portion configured to be secured to a joist and a top portion configured to support a beam to which a floor surface may be secured. The top portion is slidably connected to the base portion such that a height of the top portion above the floor support joist is adjustable. The top portion may be slidably received within the base portion in an internal channel which may comprise a polygonal shape. The top portion may comprise a mounting portion for receiving a bean, the mounting portion may comprise a support surface and at least one sidewall, preferably in the form of a U-shaped structure. A flange may project from the base portion, optionally from an edge of a bottom surface.

Description

FIELD The present invention relates to a raised flooring apparatus, and in particular but not exclusively to a height-adjustable raised flooring apparatus. BACKGROUND Loft areas in buildings such as houses provide a convenient space for additional storage. Typically loft storage is provided by laying boards on platforms or legs attached to the roof joists to provide a raised surface with the boards above the loft insulation material. That is to avoid the boards squashing or compacting the insulation, which can reduce the effectiveness of the insulation material. It is also important to leave an air gap between the insulation material and the boards to allow air to circulate in order to prevent condensation in the loft area. However, in many buildings the roof joists are at different heights and are not level with one another That can result in an unlevel loft surface, which is both inconvenient and potentially unsafe for a user. Unlevel joists can result in the airgap between the boards and the insulation material being insufficient or non-existent in some areas. Different buildings may also have different thicknesses of insulation material present. If a greater thickness of insulation material is present than required by regulation (which is typically 270 mm thickness of insulation material), conventional platforms or legs for providing a raised loft surface may result in an insufficient or non-existent air gap between the boards and the insulation material. The present invention has been devised with the foregoing in mind. SUMMARY According to a first aspect there is provided a height-adjustable loft stilt. The loft stilt may comprise a base portion configured to be secured to a joist. The loft stilt may also comprise a top portion configured to support a beam. The top portion may be slidably connected to the base portion such that a height of the top portion above the joist is adjustable. The base portion and the top portion being slidably connected to one another may provide a simple and convenient mechanism for adjusting a height of the loft stilt. That may allow the loft stilts to easily accommodate uneven or unlevel joists whilst still providing a level platform for a loft floor. That may also allow a sufficient air gap to be provided between boards secured to the beams and the insulation material in the loft, regardless of the thickness of the insulation material. That may also enable height adjustment of the loft stilt using movement along a single axis or using a single degree of freedom. The height of the loft stilt may therefore be easily adjusted during or after installation whilst retaining or maintaining a position or alignment of the loft stilt along other axes. That may allow the height of the loft stilt to be adjusted, for example to make corrections or adjustments to a height of the loft stilt, whilst minimizing a number of fixtures or components (such as beams supported by the top portion) required to be disconnected from the loft stilt to do so. That may increase ease and speed of installation of the loft stilts and of the loft floor as a whole. In particular, that may simplify height adjustment of an already installed loft floor, as only boards connected to the beam supported by the top portion may need to be removed in order for the height of the loft stilt to be adjusted. That may be particularly advantageous to allow different and / or additional insulation materials to be accommodated after installation (for example, due to development of improved insulation materials or in accordance with any change in legislation or regulation). One of the base portion and the top portion may be slidably received within the other of the base portion and the top portion. One of the base portion and the top portion may comprise an internal channel. The other of the base portion and the top portion may be at least partially slidably received in the internal channel. That may provide a loft stilt having a more compact structure. That may also improve a structural rigidity of the loft stilt (and the resulting loft floor), for example by constraining relative movement between the base portion and the top portion across a range of different heights of the top portion above the joist. The base portion and the top portion may be slidably connected to one another such sliding surfaces of the base portion and the top portion are in substantially point contact or line contact with one another. That may enable a smooth sliding movement between the base portion and the top portion, without compromising a structural rigidity or strength of the loft stilt. A part of the base portion or the top portion to be slidably received in the internal channel may comprise a substantially similar or complementary cross-sectional shape to a cross-sectional shape of the internal channel. The internal channel may comprise a polygonal cross-sectional shape. A part of the base portion or the top portion to be slidably received in the internal channel comprises a complementary polygonal cross-sectional shape. The polygonal cross-section may be a square or rectangular cross-sectional shape. That may inhibit or constrain relative rotation between the base portion and the top portion, which may increase a structural rigidity and stability of the loft stilt (and the resulting loft floor). The top portion may comprise a mounting portion configured to receive a beam. The mounting portion may comprise a support surface. The mounting portion may also comprise at least one sidewall extending from an edge of the support surface. The support surface may be substantially horizontal in use (for example, when the loft stilt is secured to a joist). The sidewall may be substantially vertical in use, and may extend generally away from the base portion (for example, in a generally upward direction when the loft stilt is secured to a joist). The sidewall may enable improved alignment of adjacent loft stilts and of beams extending between adjacent loft stilts. Improved alignment of loft stilts and beams may improve structural strength and rigidity of the loft floor as a whole. The sidewall may also act to retain the beam in place on the loft stilt during installation and use. The sidewall may provide a guide surface for alignment whilst still enabling movement of the beam on the support surface for correct alignment. The structure of the mounting portion may also allow drop-in installation of beams onto the loft stilts from above with substantially correct alignment, once the loft stilts are in place on joists. That may improve ease and speed of installation of the loft stilts and of the loft floor as a whole. The structure of the mounting portion may also enable the loft stilt to be used with any suitable beam, and need not require a specific beam having a particular structure to connect to each loft stilt. The mounting portion may comprise the support surface and a pair of sidewalls forming a substantially U-shaped structure. The substantially U-shaped structure of the mounting portion may further improve alignment of adjacent loft stilts and / or of beams extending between adjacent loft stilts, by further constraining movement of the beam on the support surface. That may also more securely retain the beam in place on the loft stilt during installation and use. At least one sidewall may comprise an aperture configured to receive a fastener. That may enable a beam to be secured to the mounting portion of the loft stilt. The loft stilt may further comprise a flange extending from a bottom surface of the base portion configured to contact a joist. The flange may extend from an edge of the bottom surface. Different joists may have different thicknesses. The flange may allow the loft stilt to be properly located on a joist irrespective of the width of the joist, by providing a guide surface for aligning with an edge of the joist. The loft stilt may further comprise means for securing the top portion at a desired height above a joist. The loft stilt may comprise means for securing the top portion at a desired height or position relative to the base portion. The loft stilt may comprise a releasable locking mechanism configured to secure the top portion at a desired height above a joist. That may enable the loft stilt to be securely installed at or adjusted to the correct or desired height relative to the joist on which the loft stilt is secured. That may also further increase structural rigidity of the loft stilt across a range of different heights of the top portion above the joist. The base portion and the top portion may comprise complementary apertures which are configured to be aligned with one another to select a desired height of the top portion above a joist. The loft stilt may further comprise an elongate bar or pin configured to be received through the complementary apertures, when aligned, to secure the top portion at the desired height. That may provide a simple and convenience mechanism for height adjustment during and after installation. One of the base portion and the top portion may comprise a primary aperture. The other of the base portion and the top portion may comprise a plurality of secondary apertures. The secondary apertures may be spaced apart from one another at regular intervals. The plurality of apertures may be spaced apart from one another along a direction substantially parallel to a sliding direction of the loft stilt. The one of the base portion and the top portion may further comprise a second primary aperture. The two primary apertures may be separate from one another but spatially overlap one another along a direction substantially parallel to a sliding direction of the loft stilt. That may provide finer height adjustment than the regular increments provided by the plurality of secondary adjustments. That may allow the loft stilt to provide a substantially flat loft floor whilst accommodating joists which may not be level with one another. That may allow the resulting loft floor to be properly supported across its full area, rather than spanning over unlevel joists (i.e. missing out loft stilts for unlevel joists) as typically occurs when installing conventional loft stilt systems. The base portion may comprise a central section to which the top portion is slidably connected. The base portion may also comprise a side section extending from the central section. The side section may be tapered such that a bottom surface of the base portion configured to contact a joist is the widest part of the base portion. The side section may extend from the central section such that the side section extends away from the central section along a longitudinal direction of the joist in use. That may improve a stability and structural strength of the loft stilt (and the resulting loft floor) when the loft stilt is secured to a joist, particularly in a direction substantially parallel to a longitudinal direction of the joist. The side section may comprise a ribbed structure. The ribbed structure may comprise or define plurality of substantially triangular structures or areas. The ribbed structure may comprise a pair of primary ribs extending from the central section. The primary ribs may be connected to one another by one or more secondary ribs. The secondary ribs may be connected between the primary ribs to form the plurality of substantially triangular areas. The primary ribs may be substantially parallel to one another. The ribbed structure of the side section may provide structural support whilst minimising a weight of the loft stilt. That may also improve a structural strength and rigidity of the loft stilt 6 (and the resulting loft floor) when the loft stilt is secured to a joist, particularly in a direction substantially perpendicular to a longitudinal direction of the joist. The base portion may comprise a pair of side sections extending from opposing sides of the central section. That may maximise a stability and structural strength of the loft stilt by providing symmetrical support to the central section. According to a second aspect, there is provided a loft stilt. The loft stilt may comprise amounting portion configured to receive a beam. The mounting portion may comprise a support surface. The mounting portion may also comprise at least one sidewall extending from an edge of the support surface. The sidewall may enable improved alignment of adjacent loft stilts and of beams extending between adjacent loft stilts. Improved alignment of loft stilts and beams may improve structural strength and rigidity of the loft floor as a whole. The sidewall may also act to retain the beam in place on the loft stilt during installation and use. The si de wall may provide a guide surface for alignment whilst still enabling movement of the beam on the support surface for correct alignment. The structure of the mounting portion may also allow drop-in installation of beams onto the loft stilts from above with substantially correct alignment, once the loft stilts are in place on joists. That may improve ease and speed of installation of the loft stilts and of the loft floor as a whole. The structure of the mounting portion may also enable the loft stilt to be used with any suitable beam, and need not require a specific beam having a particular structure to connect to each loft stilt. The support surface may be substantially horizontal in use (for example, when the loft stilt is secured to a joist). Tire sidewall may be substantially vertical in use, and may extend generally away from the base portion (for example, in a generally upward direction when the loft stilt is secured to a joist). The mounting portion may comprise the support surface and a pair of sidewalls forming a substantially U-shaped structure. The substantially U-shaped structure of the mounting portion may further improve alignment of adjacent loft stilts and / or of beams extending between adjacent loft stilts, by further constraining 7 movement of the beam on the support surface. That may also more securely retain the beam in place on the loft stilt during installation and use. At least one sidewall may comprise an aperture configured to receive a fastener. That may enable a beam to be secured to the mounting portion of the loft stilt. The loft stilt may further comprise a flange extending from a bottom surface of the loft stilt configured to contact a joist. The flange may extend from an edge of the bottom surface. Different joists may have different thicknesses. The flange may allow the loft stilt to be properly located on a joist irrespective of the width of the joist, by providing a guide surface for aligning with an edge of the joist. The loft stilt of the second aspect may comprise one or more features of the loft stilt of the first aspect, and vice versa. According to a third aspect there is provided an apparatus for providing a raised floor surface. The apparatus may comprise a base portion configured to be secured to a floor support structure, for example a joist. The apparatus may also comprise a top portion configured to support a beam to which a floor surface, for example a board, may be secured. The top portion may be slidably connected to the base portion such that a height of the top portion above the floor support structure is adjustable. The apparatus of the third aspect may comprise one or more features of the loft stilt of the first aspect and / or the second aspect, and vice versa. Features which are described in the context of separate aspects and embodiments of the invention may be used together and / or be interchangeable wherever possible. Similarly, where features are described in the context of a single embodiment for brevity, those features may also be provided separately or in any suitable sub-combination. BRIEF DESCRIPTION OF DRAWINGS Embodiments of the invention will now be described by way of example only with reference to the following drawings in which: FIG. 1A shows a height-adjustable loft stilt according to an embodiment of the present invention; FIGs. IB and IC respectively show a base portion and a top portion of the height -adjustable loft stilt shown in FIG. 1A; FIG. 2 shows a beam B extending between adjacent loft stilts located on different joists J; FIG. 3 shows a height-adjustable loft stilt according to another embodiment of the present invention; FIG. 4 shows a method of installing a loft floor using the height-adjustable loft stilt shown in FIGs. 1, 2 and 3; and FIG. 5 shows a method of adjusting a height of an already installed loft floor support by a plurality of the height-adjustable loft stilts shown in FIGs. 1, 2 and 3. Like reference numerals in different Figures may represent like elements. DETAILED DESCRIPTION Figure 1A shows a height-adjustable loft stilt 100 according to an embodiment of the present invention. The loft stilt 100 comprises a base portion 105 configured be secured to a joist J. The loft stilt 100 also comprises a top portion 120 configured to support a beam B to which a board such as a loft board can be secured. The top portion 120 is slidably connected to the base portion 105 such that a height of the top portion 120 above the joist J is adjustable. The top portion 120 being slidably connected to the base portion 105 in this manner allows a height of the top portion 120 above the joist J to be adjusted by sliding the top portion 120 relative to the base portion 105. Figures IB and IC respectively show the base portion 105 and the top portion 120 separately from one another. In the embodiment shown, the top portion 120 is slidably received within the base portion 105. The base portion 105 comprises an internal channel 106 in which a main body 121 of the top portion 120 is slidably received. The main body 121 of the top portion 120 and the internal channel 106 of the base portion 105 are both substantially elongate structures. The internal 9 channel 106 extends substantially full a through depth of the base portion 105 to maximise the height variation that can be achieved, although that is not essential. The main body 121 and the internal channel 106 also have complementary substantially square cross-sectional shapes. However, that is not essential, and the main body 121 and the internal channel 106 may each comprise complementary cross-sectional shapes of any suitable shape, for example a polygonal cross-sectional shape (e.g., triangular, rectangular, pentagonal, hexagonal, heptagonal, octagonal etc.) or a circular cross-sectional shape. The main body 121 may also comprise a cross-sectional shape comprising one or more points or lobes (for example, a star shape, a cross shape, an X shape etc.) to provide point or line contact between the main body 121 and the internal channel 106 for smooth sliding movement. The cross-sectional shape of the main body 121 comprising points or lobes may be complementary to the cross-sectional shape of the internal channel 106, for example a square or rectangular internal channel 106 may be paired with a cross-shaped or X-shaped main body 121, a n-sided polygonal internal channel 106 may be paired with a main body 121 comprising n points or lobes. It will also be appreciated the main body 121 and the internal channel 106 may not have complementary cross-sectional shapes, but the main body 121 may still be slidably received within the internal channel 106. Alternatively, the base portion 105 may be slidably received within the top portion 120 to slidably connect the two components. For example, the top portion 120 may form a sleeve structure at least partially surrounding a part of the base portion 105. The sleeve structure may define a channel in which the base portion 105 can slide relative to the top portion 120. In another alternative, the base portion 105 and the top portion 120 may be positioned adjacent one another (for example, substantially side-by-side) rather than nested within one another, with the top portion 120 slidably connected to the base portion 105 such that the top portion 120 slides along an outside of the base portion 105. The loft stilt 100 comprises a releasable locking mechanism configured to secure the top portion 120 at a desired height above the joist J, by securing the top portion 120 in a desired position relative to the base portion 1 05 after sliding the top portion 120 relative to the base portion 1 05. In the embodiment shown, the base portion 105 and the top portion 120 comprise complementary apertures 107, 122 which are configured to be aligned with one another by sliding the top portion 120 relative to the base portion 105 to select a desired height of the top portion 120 above the joist J. The loft stilt 100 also comprises an elongate pin 140 configured to received through the complementary apertures 107, 122 when aligned, to secure the top portion 120 at the desired height. The pin 140 may be removed from the apertures 107, 122 in order to adjust the height of the top portion 120 before being reinserted into aligned apertures 107, 122. In the embodiment shown, the pin 140 is a steel pin, although that is not essential. The main body 121 of the top portion 120 comprises a plurality of apertures 122 spaced apart from one another at regular intervals along a direction substantially parallel to a sliding direction of the top portion 120 within the base portion 105. The apertures 122 are provided along substantially a full length of the elongate main body 121 to maximise the height variation that can be achieved, although that is not essential. The main body 121 comprises two sidewalls 123 extending substantially parallel along the sliding direction, connected by a plurality of struts or ribs 124. The ribs 124 are equally spaced apart from one another to define slots forming the plurality of apertures 122. In addition to providing the apertures 122, the ribbed structure of the main body 121 also provides additional strength to the top portion 120 whilst reducing its weight. However, it will be appreciated the plurality of apertures 122 may alternatively comprise a plurality of holes or recesses provided in the top portion 120 which can be aligned with the aperture 107 of the base portion 105. The ribs 124 are spaced apart approximately 12 mm from one another to allow incremental height adjustment of approximately 12 mm, although it will be appreciated any suitable spacing of the apertures 122 may alternatively be used (for example, between substantially 5 mm and substantially 25 mm). The apertures 122 of the top portion 120 are also referred to herein as “secondary apertures” to clearly distinguish the apertures 122 from the aperture 107 of the base portion 105. Likewise, the apertures 107 of the base portion 105 are also referred to herein as “primary apertures”. The aperture 107 of the base portion 105 is provided on or adjacent atop of the base portion 105 (that is, an end of the base portion 105 that is furthest from the joist J in use), to maximise the height variation that can be achieved. In the embodiment shown, the base portion 105 comprises two apertures 107A, 107B. The apertures 107A, 107B are provided separately from one another, but overlap one another along the sliding direction. That is, a top point of the aperture 107B is positioned higher on the base portion 105 (further from the joist J) than a bottom point of the aperture I07A. That provides an additional mechanism for providing finer incremental height adjustment than provided by the apertures 122 of the top portion 120, for example to account for unlevel joists J. That is shown in Figure 2, with the top portion 120 of the loft stilt 100 on the left side secured to the respective base portion 105 by passing the pin 140 through the aperture 107A, and the top portion 120 of the loft stilt 100 on the right side secured to the respective base portion 105 by passing the pin 140 through the aperture 107B. In the embodiment shown, the apertures I07B overlap one another or are offset from one another along the sliding direction by a distance of approximately 5 mm, although it will be appreciated any suitable distance may alternatively be used (for example, between substantially 1 mm and substantially 10 mm). In some embodiments, the base portion 105 and the top portion 120 comprise complementary engaging features configured to provide tactile feedback to a user indicating the apertures 107, 122 are aligned with one another. For example, one or more surfaces of the base portion 105 and the top portion 120 which are configured to slide over one another may respectively comprise corresponding raised portions (such as bumps) and recessed portions (such as notches) configured to engage one another when the apertures 107, 122 are aligned with one another. That may allow a user or installer of the loft stilt 100 to feel the incremental height adjustments without having to align the apertures 107, 122 by eye. The corresponding raised and recessed portions are spaced apart from another using substantially the same spacing as for the apertures 122 of the main body 121. The raised and recessed portions may engage one another sufficiently to indicate the apertures are aligned and temporarily hold the base portion 105 and the top portion 120 in a sliding position relative to one another, without providing significant resistance to sliding movement between the base portion 105 and the top portion 120. Additionally or alternatively, an external surface of the loft stilt 100 (for example, external surfaces of the base portion 105 and / or the top portion 120) may each comprise one or more markings or indicia (such as numbered markings) enabling a user to align the apertures 107, 122 by eye or otherwise set the top portion 120 to a desired height. In the embodiment shown, when the top portion 120 is at its lowest possible height or position relative to the base portion 105, the top portion 120 is substantially 280mm above a joist J on which the loft stilt 100 is placed. That may enable the conventional thickness of 270mm of insulation material to be provided beneath a loft floor supported by the loft stilts 100 without being compressed and providing a sufficient air gap between the insulation material and the boards forming the loft floor surface. When the top portion 120 is at its highest possible height or position relative to the base portion 105 (for example, with the lowermost aperture 122 aligned with the aperture 107 of the base portion 105), the top portion 120 is substantially 440mm above a joist J on which the loft stilt 100 is placed. However, it will be appreciated the top portion 120 may be adjusted to any suitable height above the minimum height of 280mm to accommodate a wide range of thicknesses of insulation material whilst still providing a sufficient air gap above the insulation material. It will also be appreciated the top portion 120 may be secured at a desired height above a joist J using any suitable alternative means. For example, as shown in Figure 3, the top portion 120 may be secured at a desired height above a joist J using one or more shims or packers 130 provided beneath the top portion 120 and within the internal channel 106 of the base portion 105. That may enable the height of the top portion 120 above a joist J to be easily adjusted whilst the base portion 105 provides additional structural support and rigidity to the loft stilt 100 across a variety of heights due to the top portion 120 being slidably received within the internal channel 106 of the base portion 105. The packers 130 each comprise a strip of material having a suitable thickness, for example between substantially 2 mm and substantially 10 mm, to allow incremental height adjustment of the top portion 120 above a joist. Different packers 130 may each comprise a different thickness to enable a height of the top portion 120 above a joist J to be as accurate as possible. The packers 130 may be inserted into the channel 106 from a top of the internal channel 106, with the top portion 120 provided on top of the packers 130. Alternatively, the packers 130 may be inserted into the internal channel 106 from a side of the internal channel 106, for example through a side of the base portion 105 (such as through an aperture provided in the side of the base portion 105). That may enable the packers 130 to be inserted into and removed from the internal channel without requiring the top portion 120 to be removed from the internal channel 106. The aperture in the side of the base portion 105 may be selectively coverable (for example, with a hinged flap or a sliding cover) to prevent the packers 130 from being inadvertently removed from the internal channel 106 in use, whilst still enabling access to the packers 130 for convenient height adjustment without removing the top portion 130 from the internal channel 106. In another alternative, the base portion 105 and the top portion 120 may be slidably connected to one another via a ratchet mechanism to secure the top portion 120 at a desired height above a joist J. The ratchet mechanism may comprise a plurality of teeth configured to engage with a spring-loaded pawl. The ratchet mechanism may freely allow sliding motion of the top portion 120 relative to the base portion 105 in one direction (for example, upwards away from a joist J) but may prevent sliding motion of the top portion 120 relative to the base portion 105 in the opposite direction (for example, downwards towards the joist J) unless the pawl is manually disengaged from the teeth by a user. The ratchet mechanism may therefore act as a releasable locking mechanism to secure the top portion 120 at a desired height above a joist J. The teeth of the ratchet mechanism may be provided on or associated with one of the base portion 105 and the top portion 120, and the pawl may be provided on or associated with the other of the base portion 105 and the top portion 120. The teeth of the ratchet mechanism may be spaced apart from one another to allow a height of the top portion 120 above a joist J to be adjusted in desired increments. In the embodiment shown, an external surface of the sidewalls 123 of the main body 121 comprises one or more raised ribs 123a to provide point contact between the main body 121 and the internal channel 106 for smooth sliding movement, although that is not essential. The top portion 120 comprises a mounting portion 125. The mounting portion 125 is provided on a top of the main body 121, so that the mounting portion 125 is furthest from the joist J in use. The mounting portion 125 is configured to receive a beam or batten B (as shown in Figure 2) to which a board (not shown) such as a loft board can be secured to form a raised loft floor supported by the loft stilt 100. The mounting portion 125 comprises a support surface 126 and a pair of sidewalls 127 extending from opposing edges of the support surface 126 such that the mounting portion 125 is substantially U-shaped. The support surface 126 provides a flat surface which is substantially horizontal in use (when the loft stilt 100 is supported on a joist J) to support a beam B, whilst the sidewalls 127 act to retain the beam B in place on the loft stilt 100. The sidewalls 127 may also ensure the beam B is properly aligned with each loft stilt 100 and between adjacent loft stilts 100 as shown in Figure 2 (and equally that adjacent loft stilts 100 are properly aligned with one another) before fixing the beam B to the loft stilts 100 (and / or before fixing the loft stilts 100 to joists J). The sidewalls 127 each comprise apertures 128 configured to receive a fastener (not shown) in order to secure the beam B to the top portion 120. In the embodiment shown, the mounting portion 125 is configured such that the sidewalls 127 extend substantially perpendicularly to the joist J on which the loft stilt 100 is located in order to align the beam B supported by the support surface 126 substantially perpendicularly to the joist J. However, that is not essential and the mounting portion 125 may alternatively be configured to align the beam B in any suitable orientation relative to the joist J on which the loft stilt 100 is located. The opening of the U-shaped mounting structure 125 faces away from the base portion 105 (i.e., substantially upwards in use), such that a beam B can be installed onto the mounting portion 125 from above once the loft stilt 100 is placed on the joist J. A width of the support surface 126 between the sidewalls 127, and a height of the sidewalls 127 extending above the support surface 126, may be selected based on the dimensions of the beam or batten B to be received by the mounting portion 125. The width of the support surface 126 may be wider than the beam B received by the mounting portion 125, for example between substantially 2 mm and substantially 10 mm wider, such that there is sufficient space between the sidewalls 127 to allow the beam B to be well aligned between adjacent loft stilts 100 for improved structural performance, whilst also accommodating any small but tolerable misalignment of the loft stilts 100 (for example, due to twisted or non-parallel joists J on which the loft stilts 100 are mounted, or if the loft stilts 100 are already secured to the joists J but are slightly misaligned from one another). In the embodiment shown, the mounting portion 125 is configured to receive CLS batten having nominal cross-sectional dimensions of 38 mm x 63 mm (2” x 3”), and has a width of substantially 70 mm. It will be appreciated a beam B having different dimensions may alternatively be used, with the mounting portion 125 having corresponding dimensions (for example, a width of the support surface 126 and / or a height of the sidewalls 127) as required. Alternatively, the mounting portion 125 may comprise only a single sidewall 127 (for example, extending from one edge of the support surface 126) such that the mounting portion 125 is substantially L-shaped. The single sidewall 127 may have substantially the same function as the pair of sidewalls 127 in retaining the beam B on the loft stilt 100 and aligning the beam B between adjacent loft stilts 100, and allowing installation of the beam B onto the mounting portion 125 from above. In another alternative, the mounting portion 125 may comprise only the support surface 126. In some embodiments, the mounting portion 125 comprises one or more frangible portions. The frangible portions may be provided in the form of creases or narrow channels (for example, where the thickness of the mounting portion 125 is reduced compared to other areas of the mounting portion 125), and may be provided in sidewalls 127 of the mounting portion 125 and / or at the connection between the sidewalls 127 and the support surface 126. That may allow part or all of each sidewall 127 to be removed (for example, snapped off), for example to allow for multi-directional use of the mounting portion 125 or to accommodate joints or corner sections (for example, where perpendicular beams B meet one another). The base portion 105 comprises a central section 108. The internal channel 106 in which the top portion 120 is slidably received is provided in the central section 108. The apertures 107A, 107B are also provided in the central section 108. The base portion 105 further comprises side sections 109 extending from opposing lateral sides of the central section 108. The central section 108 and the side sections 109 are shown conceptually delineated from one another by dashed lines in Figure IB. The side sections 109 extend from the central section 108 such that the side sections 109 extend along a longitudinal direction of the joist J on which the loft stilt 100 is placed in use. That may increase an area of a bottom surface of the base portion 105 in contact with the joist J, and also increase a strength of the loft stilt 100, which in turn may increase stability of the loft stilt 100 on the joist J and strength of the resulting loft floor. In the embodiment shown, the side sections 109 are tapered in a generally triangular such that the bottom surface of the base portion 105 is the widest part of the base portion, although that is not essential. The triangular shape of the side sections 109 may provide a strong, stable structure with minimal additional weight. The side sections 109 are integral with the central section 108, although the side sections 109 may alternatively be separate structures which are affixed to the central section 108. That may also enable the central section 108 to be used independent from one or both side sections 109, if necessary. In that case the loft stilt 100 may not comprise any side sections 109 . In the embodiment shown, each side section 109 comprises a ribbed structure. The ribbed structure defines a plurality of substantially triangular structures or areas of the side section 109, which may provide strength whilst minimising weight of the loft stilt 100. The ribbed structure comprises a pair of primary ribs 110 extending from the central section 108. The primary ribs 110 are substantially parallel to one another, and are connected to one another by a plurality of secondary ribs 111 extending between the primary ribs 110. The secondary ribs 111 are connected between the primary ribs 110 to form the triangular structures of the ribbed structure. The base portion 105 also comprises a tab or flange 112 extending from the bottom surface of the base portion 105. In use the flange 112 extends substantially downwards beyond atop surface of a joist J on which the loft stilt 100 is placed. The flange 112 is located on an edge of the bottom surface of the base portion 105 and may be brought into engagement with a side of the joist J, to enable the loft stilt 100 to be properly and accurately positioned on the joist J before securing the loft stilt 100 to the joist J. It will be appreciated the base portion 105 may not comprise a tab or flange. In the embodiment shown, the base portion 105 and the top portion 120 of the loft stilt 100 are each manufactured from or comprise a plastic or polymeric material, for example polypropylene, acrylonitrile butadiene styrene (ABS) or any other suitable polymeric material. The polymeric material may be or comprise a glass-filled polymer. The base portion 105 and the top portion 120 are each manufactured by injection moulding, although it will be appreciated the base portion 105 and the top portion 120 may be manufactured using any suitable technique such as by machining or structural foam moulding. The base portion 105 and the top portion 120 each comprise a bright colour (for example, a bright pink, bright red, bright yellow, bright green, bright blue colour etc.) to make the loft stilt 100 as visible as possible in a loft area (which is typically a confined space) and reduce a risk of the loft stilt 100 acting as a trip hazard. Figure 4 shows a method 200 of installing a loft floor using the height-adjustable loft stilt 100 described above with respect to Figures 1A, IB, IC, 2 and 3. Step 205 of the method 200 comprises placing a plurality of loft stilts 100 on two or more joists J. Step 210 of the method 200 comprises aligning each loft stilt 100 with one or more other loft stilts 100 such that a beam B can extend between and be supported on the respective mounting portion 125 of each aligned loft stilt 100. Step 215 of the method 200 comprises securing each loft stilt 100 to the joist J on which it is placed. Step 215 may comprise securing the loft stilts 100 to the joists J in any suitable manner, for example using a fastener such as a screw' or a nail, or an adhesive etc. Step 220 of the method 200 comprises adjusting a height of each loft stilt 100 to a desired height, for example to accommodate a desired thickness of insulation material (for example, 270mm or thicker). The height of each loft stilt 100 is adjusted such that atop portion 120 of each loft stilt 100 is substantially level with the top portion 120 of the other loft stilts 100. It will also be appreciated the height of each loft stilt 100 may be set or adjusted to the desired height prior to placing the loft stilt 100 on a joist J. Step 225 of the method 200 comprises placing one or more beams B on the loft stilts 100 such that each beam B extends between the mounting portions 125 of two or more aligned loft stilts 100. It will be appreciated step 220 may alternatively take place substantially simultaneously with step 210, such that the beam(s) B may be actively used to assist in aligning the loft stilts 100. For example, the sidewall 127 of the mounting portions 125 of each loft stilt 100 may be used as a guide surface for the beam B to align each loft stilt 100 with the beam B and therefore with each of the other loft stilts 100 across which the beam B extends. In that case, the beams B may be placed on the loft stilts 100 prior to adjusting a height of each loft stilt 100 and prior to securing the loft stilts 100 to the joists J. Step 230 of the method 200 comprises securing the beam(s) B to the loft stilts 100. In an embodiment, step 230 comprises securing the beams B to the loft stilts 100 using a fastener through the apertures 120 provided in the sidewalls 127 of the mounting portion, although that is not essential. Step 235 of the method 200 comprises securing one or more boards such as loft boards to the beams B supported by the loft stilts 100. Figure 5 shows a method 300 of adjusting a height of an already installed loft floor supported by a plurality of the height-adjustable loft stilts 100 described above with respect to Figures 1A, IB, IC, 2 and 3, for example to alter a thickness of insulation material provided beneath the loft floor. Step 305 of the method 300 comprises removing one or more boards from the loft floor surface. Step 310 of the method 300 comprises adjusting a height of the loft stilts 100 located beneath the removed boards to a new desired height. In an embodiment, step 310 of the method 300 comprises removing the pin 140 from the aligned apertures 107, 122 of the relevant loft stilts 100, adjusting a height of those loft stilts 100 to a new desired height, and reinserting the pin 140 into the aligned apertures 107, 122 to secure the top portion 120 of each loft stilt 100 at the new desired height. By virtue of the top portion 120 and the base portion 105 of each loft stilt 100 being slidably connected to one another, the height of each loft stilt 100 can be adjusted without requiring any other components of the loft floor to be disconnected or removed. For example, the beams B can remain in place and secured to the top portion 120 of each loft stilt 100 whilst adjusting the height of the loft stilts 100. Step 315 of the method 300 comprises placing the one or more removed boards back onto the beams B supported by the loft stilts 100 to reform the loft floor surface. From reading the present disclosure, other variations and modifications will be apparent to the skilled person. Such variations and modifications may involve equivalent and other features which are already known in the art of loft stilts and which may be used instead of, or in addition to, features already described herein. Although the appended claims are directed to particular combinations of features, it should be understood that the scope of the disclosure of the present invention also includes any novel feature or any novel combination of features disclosed herein either explicitly or implicitly or any generalisation thereof, whether or not it relates to the same invention as presently claimed in any claim and whether or not it mitigates any or all of the same technical problems as does the present invention. Features which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. The applicant hereby gives notice that new claims may be formulated to such features and / or combinations of such features during the prosecution of the present application or of any further application derived therefrom. For the sake of completeness, it is also stated that the term “comprising" does not exclude other elements or steps, the term “a” or “an” does not exclude a plurality, and any reference signs in the claims shall not be construed as limiting the scope of the claims.

Claims

1. A height-adjustable loft stilt (100), comprising:a base portion (105) configured to be secured to a joist; and5 a top portion (120) configured to support a beam;wherein the top portion (120) is slidably connected to the base portion (105) such that a height of the top portion above the joist is adjustable; and whereinthe base portion (105) and the top portion (120) comprise complementary apertures (107, 122) which are configured to be aligned with one another to select a 10 desired height of the top portion (120) above a joist; andthe loft stilt (100) further comprises an elongate bar or pin (140) configured to be slidably received through the complementary apertures (107, 122), when aligned, to secure the top portion (120) at the desired height.15 2. The loft stilt (100) of claim 1, wherein the top portion (120) is slidably received withinthe base portion (105).

3. The loft stilt (100) of claim 2, wherein:one of the base portion (105) and the top portion (120) comprises an internal channel20 (106); andthe other of the base portion (105) and the top portion (120) is at least partially slidably received in the internal channel (106).

4. The loft stilt (100) of claim 3, wherein:25 the internal channel (106) comprises a polygonal cross-sectional shape; anda part of the base portion (105) or the top portion (120) configured to be slidably received in the internal channel (106) comprises a complementary polygonal cross-sectional shape.

5. The loft stilt (100) of any preceding claim, wherein:30 the top portion (120) comprises a mounting portion (125) configured to receive a beam,the mounting portion (125) comprising:a support surface (126); andat least one sidewall (127) extending from an edge of the support surface (126).35 6. The loft stilt (100) of claim 5, wherein the mounting portion (125) comprises the supportsurface (126) and a pair of sidewalls (127) forming a substantially U-shaped structure.14 05 257. The loft stilt (100) of claim 5 or of claim 6, wherein at least one sidewall (127) comprises an aperture (128) configured to receive a fastener.

8. The loft stilt (100) of any preceding claim, further comprising a flange (112) extending 5 from a bottom surface of the base portion (105) configured to contact a joist, and optionally wherein the flange (112) extends from an edge of the bottom surface.

9. The loft stilt (100) of any preceding claim, wherein:one of the base portion (105) and the top portion (120) comprises a primary aperture 10 (107); andthe other of the base portion (105) and the top portion (120) comprises a plurality of secondary apertures (122) spaced apart from one another at regular intervals.

10. The loft stilt (100) of claim 9, wherein the one of the base portion (105) and the top 15 portion (120) further comprises a second primary aperture (107B), the two primary apertures (107A, 107B) separate from one another but spatially overlap one another along a direction substantially parallel to a sliding direction of the loft stilt (100).

11. The loft stilt (100) of any preceding claim, wherein the base portion (105) comprises: 20 a central section (108) to which the top portion (120) is slidably connected; anda side section (109) extending from the central section (108) and tapered such that a bottom surface of the base portion (105) configured to contact a joist is the widest part of the base portion (105).25 12. The loft stilt (100) of claim 11, wherein the side section (109) comprises a ribbedstructure.

13. The loft stilt (100) of claim 11 or of claim 12, wherein the base portion (105) comprises a pair of side sections (109) extending from opposing sides of the central section (108).

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