Mineral wool for green roofs

Abstract

Method of providing a growing medium (4) for a green roof (5) on a roof of a building (3), comprising the steps of: • - mixing mineral wool and a solvent to form a growing suspension (2); • - providing the growing suspension (2, 8) on a roof (5) of the building (3); and • - letting the growing suspension (2, 8) rest on the roof (5) of the building (3) such that the mineral wool settles on the roof (5).

Description

[0001] Title: Mineral wool for green roofs

[0002] The invention relates to a method of providing a growing medium for a green roof on a roof of a building, a growing suspension and a building comprising a green roof.

[0003] A green roof is a roof of a building that is partially or completely covered with vegetation and a growing medium. This may be planted over a waterproofing membrane. Additional layers of material may be included, such as a root barrier, a drainage and an irrigation system. Green roofs can vary in type and complexity, ranging from simple extensive roofs with low- maintenance plants to intensive roofs with a variety of plant species and even small trees.

[0004] A green roof has a few benefits compared to conventional roofs of a building. A green roof can have environmental benefits, such as improved air quality and supporting local biodiversity, and economic benefits, such as improving the energy efficiency of a building by insulating the roof and thus reducing heating and cooling costs and by extending the roof life by protecting the roofing materials from UV radiation and extreme temperature fluctuations. Furthermore, green roofs are able to absorb water, providing the possibility to mitigate the negative effects of for example excessive rainfall. In addition, the use of green roofs has a positive effect on the use of solar panels in the sense that a more efficient operation of such panels can be achieved. Thus, in general, green roofs can have positive effects regarding the health and wellbeing of the population, while in addition increasing the monetary value of properties and / or residences equipped with said green roof.

[0005] Installing a green roof may be challenging, as providing the growing medium is a laborious task. The growing medium may have a mineral wool material to retain water for growing and sustaining vegetation. Mineral wool is commonly applied in plates or rolls of material, which are unrolled on the roof, mostly flat roofs.

[0006] The invention aims to counteract the above disadvantages, preferably while retaining the advantages. More specifically, the invention aims to provide for a method of providing a growing medium of a green roof on a roof of a building that is more convenient than the commonly used methods. Furthermore, the method may allow for providing the growing medium on most, if not all, types of existing roofs including pitched roofs.

[0007] Therefore, the invention provides for a method of providing a growing medium on a green roof on a roof of a building, in particular according to claim 1. The method comprises the steps of:

[0008] - mixing mineral wool and a solvent to form a growing suspension;

[0009] - providing the growing suspension on a roof of a building; and

[0010] - letting the growing suspension rest on the roof of the building such that the mineral wool settles on the roof.

[0011] Mineral wool may be a fibrous material formed by spinning or drawing molten mineral or rock materials. Mineral wool may be produced such that it can hold large quantities of water and air. This may facilitate the growth of roots of vegetation of which the green roof is made. In addition, the fibrous structure of mineral wool may provide good mechanical properties to hold the vegetation stable, e.g. it prevents vegetation from moving relative to the roof it is provided on. The mineral wool can be stone wool, which is a common available mineral wool. In addition, stone wool has the advantage of being durable, resulting in a long lifespan. Mineral wool is sustainable, as it is made from natural volcanic rock and recycled material, making it an environmentally friendly option.

[0012] A porous material can be added to the mineral wool and the solvent during mixing to form the growing suspension. The porous material can settle on the roof when the growing suspension rests on the roof. The porous material may provide structural integrity to the growing medium, e.g. making it more resistant to unwanted movement on the roof due to environmental effects, while also improving the water retaining capabilities. A preferred porous material can be lava stone, or volcanic rock, as it is a relatively lightweight compared to other porous materials, e.g. rocks, and may provide excellent aeration properties and nutrient retention. These two properties facilitate the growth of the vegetation on the green roof.

[0013] The mineral wool, optionally the porous material, and solvent can be mixed in to a growing suspension. The resulting growing suspension is a semi-liquid, or sludge-like material that may be displaced using a pump. Due to the semi-liquid physical properties of the growing suspension, it can be conveniently provided on roofs, even in otherwise difficult to reach locations. The resulting growing medium, either with or without the porous material, can be lighter in terms of weight in comparison to commonly used growing media, e.g. up to 30%. In addition, the structure of the growing medium is more compact with respect to the granular structure of existing growing media, which is of great importance for installation on pitched roofs. The use of the growing suspension according to the invention, either as such or mixed with a conventional medium, can result in a growing medium which is more compact while having a stronger fixation to the roof. Furthermore, by providing the growing medium as a liquid growing suspension on a roof, installation of the growing medium can be performed quicker when compared to conventional growing media. Additionally, the growing medium is less susceptible to erosion.

[0014] The growing suspension may be considered an unstable mixture, thus after a while when left alone, the solvent and the solids present in the solvent start to segregate again. For example, the mineral wool may form collect and form a solid material on a surface, for example the roof. The solid material formed on the surface, comprising the mineral wool, is the growing medium on which the plants of the green roof may be provided. The solvent, present on top of the growing medium, may slowly evaporate or may flow towards a drain, for example a drain provided at a low point on the roof.

[0015] In an embodiment a binder may be provided in the growing suspension. The binder may provide for temporary stiffness to the solids suspended in the solvent, e.g. the mineral wool. A more stiff growing suspension may be more conveniently provided on a roof, as it is more prone to maintain its shape and less likely to move due to external forces, e.g. gravity. Preferably the binder is a binder that flushes out of the growing suspension and I or the suspended mineral wool when exposed to water, e.g. rain.

[0016] In order to facilitate removal of the solvent, and thus more quickly forming the growing medium on the roof, the method may further comprise the step of:

[0017] - draining the solvent from the growing suspension when the growing suspension is resting on the roof of the building. This may be either draining by actively facilitating flowing of the solvent away from the roof on which it is provided, e.g. by providing draining points such as rain pipes. Additionally, or alternatively, evaporation of the solvent may be evaporated by providing large fans to promote airflow and thus evaporation of the solvent. After sufficient solvent has evaporated and I or flowed out of the growing suspension, and the remaining material behaves as a solid, even if it may still contain some solvent. The remaining material, a mix of mineral wool, and optionally porous material, is the growing medium on which vegetation may grow.

[0018] The growing suspension may be supplemented with a substance promoting growth of vegetation. These substances may either be substances that contain additional nutrients for the vegetation, in order to support the growth and the sustaining of the vegetation. Alternatively, the substances may promote retaining of water such that the vegetation has sufficient water, even when it has not rained for a while. The mineral wool and porous material may be homogenously mixed in the solvent, resulting in a growing suspension that has substantially the same properties through the volume. In other words, the materials that make up the growing suspension are evenly distributed in the growing suspension, making it more reliable and convenient to use the growing suspension.

[0019] The solvent, in which the mineral wool and porous material are suspended, can be water. Water is commonly available, abundant and has no negative environmental impact. As a result, it is a relatively cheap and sustainable solvent. The solvent may additionally comprise a substance for promoting the growth of vegetation, such as a liquid fertilizer. During mixing of the growing suspension, abundant water may be added as a solvent such that the mineral wool and porous material are suspended in the water. However, once the growing suspension has been provided on the roof and the mineral wool has been settled, renewed exposure of the mineral wool to water, i.e. the solvent, does not turn the growing medium back to the growing suspension as there is no mixing involved. Thus, the growing medium remains provided on the green roof.

[0020] The method may further comprise the steps of:

[0021] -mounting a receptacle on the roof of a building, wherein said receptacle comprises an opening, wherein said opening is arranged to receive the growing suspension; and

[0022] - providing the growing suspension in the receptacle. Optionally, the growing suspension can be provided in the receptacle before the receptacle is mounted on the roof of the building.

[0023] The optionally provided receptacle, or container, may further improve structural integrity of the growing suspension, and I or the growing medium and the vegetation on the roof. This may be in particular advantageous for providing structural integrity to the growing medium and vegetation if the growing medium and vegetation covers a large amount of square meter of the surface of a pitched roof. In such case, in particular if the growing medium comprises a lot of water due to e.g. rainfall, the growing medium may become too heavy locally. Separating the growing medium into sections, e.g. using receptacles, may prevent this. Additionally or alternatively, the receptacles may prevent water flowing downward in case the green roof is provided on a pitched roof. This may prevent a higher provided section of the green roof, i.e. closer towards the top of the pitched roof, from drying out while a lower provided section of the green roof has an excess of water, which will be drained away and I or evaporated since the green roof is saturated and no more water can be held within the green roof components, e.g. the porous material and the mineral wool. The receptacles installed on the roof before carrying the growing suspension may be of a larger size than receptacles filled at a remote location and later installed on the roof. For example, the installed receptacles may be much wider than the remote filled receptacles that are commonly square shaped. Specifically, the installed receptacles may have a width between 30 centimeters and 1 meter.

[0024] The method may further comprise the steps of:

[0025] - providing deposition means having an inlet for receiving a growing suspension, an outlet nozzle, and a pump arranged to drive growing suspension from the inlet to the outlet nozzle during use;

[0026] - feeding growing suspension to the deposition means such that the deposition means transport the growing suspension from the inlet to the roof of a building via the pump and outlet nozzle. Providing a pump, having a nozzle, preferably connected to the pump via a hose, may facilitate placement of the growing suspension on the roof. The person deploying the growing suspension on the roof now no longer needs to carry large sheets of mineral wool but instead may just carry the nozzle. Thus, it is possible to feed the growing suspension remotely, for example on the ground floor next to the building which roof is being provided with the growing suspension, at a convenient location to the pump system. In a second aspect of the invention, a growing suspension is provided. The growing suspension comprises mineral wool, porous material, preferably lava stone, and a solvent. The volume ratio of lava stone to mineral wool can be between 1:20 and 10:7, preferably between 1:10 and 3:1, more preferably between 1:2 and 3:5, and most preferably 1:1. This mixture ratio allows for the suspension to be sufficiently lightweight while maintaining sufficient structural integrity, thereby preventing the growing suspension once dried and after transforming to growing medium, from detaching from the roof.

[0027] The growing suspension may further comprise at least one of compost, biochar, perlite, vermiculite, coconut coir, expanded clay aggregates, peat moss, worm castings and zeolite. These materials may be added to the growing suspension, and thus also are part of the growing medium once the growing suspension has dried, to further facilitate growing of the vegetation on the growing medium.

[0028] In an alternative application of the growing suspension, the growing suspension may be used to reinforce a vegetation mat, e.g. a sedum mat. After the growing medium is provided on a roof, vegetation needs to be provided to finish the green roof. The vegetation for a green roof may be commonly provided as a sedum mat. A roll of sedum may in such case be transported to the roof and unrolled on the growing medium. After a certain time has passed, the sedum has rooted in the growing medium and is thus firmly attached to the growing medium. Commonly available sedum mats may be vulnerable to damage while being transported or provided on the roof. In order to reinforce the vegetation mat, or sedum mat, a producer of these mats may first provide a layer of growing suspension. On this layer of growing suspension, the vegetation layer is provided such that the vegetation layer starts to attach to the growing medium after some time has passed. Once the vegetation, e.g. sedum, is attached to the growing medium, a reinforced sedum mat has been produced that can be rolled up and transported to a green roof.

[0029] The growing suspension can be provided on the roof of a building, to form a growing medium at the location a green roof will be constructed, or may be provided at a separate location to reinforce a vegetation top layer. For example, the growing suspension may be provided at a production facility to create a growing medium that is mounted on a roof located elsewhere. In such a case, a preferred shape for the growing medium can be provided by placing the growing suspension in a predefined shape, e.g. a rectangle or a triangle, for example a shape corresponding to the roof on which the green roof is being constructed. Optionally, materials facilitating the growth of vegetation on the growing medium or that provide additional structural integrity, such as coconut coir, compost and peat moss, may be provided in the growing suspension. Once the growing suspension has settled, and the solvent has been drained, the growing medium remains and may be transported to a building in which it may be provided.

[0030] In a third aspect of the invention, a building is provided. The building comprises a roof and a layer of growing suspension as previously described. The layer of growing suspension has substantially the same thickness. The growing medium may be provided using the previously described method. The roof of the building may be flat or inclined with respect to a horizontal plane. The roof preferably forms an angle between 15 and 75 degrees with respect to the horizontal plane. In case the grown suspension is provided on an inclined roof, it may be advantageous to provide the growing suspension in receptacles or by providing barrier elements on the roof to prevent the growing suspension, and I or the growing medium in a later stage, from sliding off the roof. The barrier elements may be wooden planks, e.g. wooden planks having a height of 3-10 centimeters, provided with their longitudinal axis parallel to the horizon. The barrier elements may be spaced apart between 20 and 30 centimeters in a direction transverse to the horizon, i.e. from the top of the roof towards the bottom of the roof.

[0031] Further advantageous aspects of the invention are set out in the description and appended claims.

[0032] The technical features described in the paragraphs and sentences above can be isolated from the context, and the isolated technical features from the different paragraphs and sentences can be combined. Such combinations are herewith specifically disclosed in this description.

[0033] The invention will further be elucidated on the basis of exemplary embodiments which are represented in the drawings. The exemplary embodiments are given by way of non-limitative illustration of the invention.

[0034] In the drawings:

[0035] Fig. 1 shows a schematic isometric view of a mixer for mixing a growing suspension for a green roof on a roof of a building according to the invention;

[0036] Fig. 2 shows a schematic perspective view of a building on which a growing medium for a green roof is being installed on the roof according to the invention;

[0037] Fig. 3 shows a schematic perspective view of a building on which a growing medium for a green roof is being installed in one or more receptacles which are mounted on top of the roof according to the invention; and

[0038] Fig. 4 shows a schematic front view of a building with a growing medium for a green roof on the roof of the building.

[0039] In this description embodiments of the invention will be described with reference to the drawings by way of example only. These embodiments should by no means be understood as limiting the scope of the disclosure. At least all combinations of aspects, elements and features of the embodiments shown and discussed are also considered to have been disclosed herein. In this description the same or similar elements and features will be referred to by the same or similar reference signs. The drawings are not necessarily to scale, and can show exaggerations in order to more clearly show features of the claimed invention.

[0040] In this description wording like substantially and generally should be understood as meaning that relatively small deviations from the feature or value they refer to are also considered to be covered, for example deviations of 20% or less, such as 15% or less or 10% or less, unless specified differently.

[0041] Fig. 1 shows a schematic perspective view of a mixer 1 for mixing a growing suspension 2 for a green roof on a roof of a building according to the invention. In the shown example, the growing suspension 2 is obtained by first mixing mineral wool, an optional porous material and a solvent to form the growing suspension 2, for example in a drum 12 of the mixer 1. The mixer can be a commercially available mixer, e.g. a mixer used to make concrete. In the example, the growing suspension 2 comprises compost and biochar in order to facilitate grown of vegetation on the growing medium that is left after the growing suspension 2 has settled. The mineral wool and porous material of the growing suspension are homogenously throughout in the solvent. After the growing suspension 2 is provided on the roof, the solid materials in the suspension settle on the roof. In the depicted example, these sold materials are mineral wool, porous material, e.g. stone wool and lava stone, compost and biochar. The volume ratio of lava stone to mineral wool is between 1:20 and 10:7, e.g. 1:1. The proposed volume ratio allows for a sufficiently firm growing medium 4, while simultaneously keeping it light weight. In the shown example, the solvent used is water. In the example a binder has been provided to the growing suspension. The binder is a binder that flushes out of the settled mineral wool and porous material when exposed to water, e.g. rain. Fig. 2 shows a schematic perspective view of an example of a building 3 on which a growing medium 4 for a green roof 5 is being installed. Barrier elements 14 have been installed in the roof 5, said barrier elements 14 being wooden planks. Said wooden planks 14 have their longitudinal direction parallel to the horizon and are spaced apart 25 centimeters in a direction transverse to the longitudinal direction of the wooden planks 14. These barrier elements 14 prevent the growing suspension 8 from sliding down the pitched roof 5 when installing, or prevents the growing medium 4 from sliding down the pitched roof 5 once the installation of the green roof has been finished. Deposition means 6 are provided having an inlet 7 for growing suspension 8, an outlet nozzle 9, and a pump 10 arranged to drive growing suspension 8 from the inlet 7 to the outlet nozzle 9 during use. The outlet nozzle 9 is intended to be aimed towards the roof 5 of a building 3, while growing suspension 8 is fed to the deposition means 6 such that the deposition means 6 transports the growing suspension 8 from the inlet 7 to the roof 5 of a building 3 via the pump 10 and outlet nozzle 9. The pump 10 used can be a commercially available pump, preferably a pump used to drive suspensions and I or liquids with a relatively high viscosity. The pump can be provided next to the building 3, as shown in the example, but may also be provided on scaffolding adjacent to the building 3 or on the roof 5 of the building. The pump 10 is in fluid connection with the nozzle 9 via a hose 12, said hosing 12 having a diameter sufficiently large to provide a steady flow of growing suspension 8 fed to the pump to the roof 5 while being small enough to facilitate handling of the nozzle 9 by a user. In the shown example, the complete surface of the roof 5 is covered by the growing suspension 8. Once the growing suspension 8 has settled and the solvent, in this example water, has been drained and I or evaporated, the remnants of the growing suspension 8 form the growing medium 4 on the roof 5. On this growing medium 4, vegetation may be provided to form a green roof. In the example, the roof 5 of the building 3 is inclined with respect to a horizontal plane, wherein the roof 5 preferably forms an angle between 15 and 75 degrees with respect to the horizontal plane. However, the method is suitable to provide growing medium 4 on roofs which form an angle with respect to the horizontal plane outside of said range, including roofs that do not form an angle with the horizontal plane such as a flat roof.

[0042] Fig. 3 shows a further example of a schematic perspective view of a building 3 on which a growing medium 4 for a green roof 5 is being installed. Instead of providing the growing medium 4 directly on the surface of the roof 5, first receptacles 11 are provided which are mounted on top of the roof 5. The receptacles 11 are provided on the roof 5 of the building 3, wherein said receptacles 11 each have an opening arranged to receive the growing suspension 8. The growing suspension 8 is provided in the receptacles 11. The receptacles 11 may be installed in a variety of configurations, for example in a row, along a longitudinal direction of the roof 5 and / or in a transverse direction of the roof 5. In the shown example, the receptacles 11 are provided in both directions and thus form a grid on the roof 5 of the building 3. Providing the growing suspension 8 in the receptacles 11 prevents water in the growing medium 4 from being moved towards the bottom of the roof 5 and thus draining the growing medium 4 towards the top of the roof 5. Additionally, the receptacles 11 may assist in providing structural integrity to the roof. Fixation of the receptacles 11 to the roof may be done by means of brackets, which may further comprise screws or similar fixations mean to secure the receptacles to the roof, while taking appropriate measures to ensure waterproofing of the roof. It will be clear to the skilled person that, while not shown in the figure, the receptacles 11 may be filled with growing suspension 7 at a location different than the roof 5, i.e. before the receptacles 11 are mounted on the roof 5. In such a case, it may be advantageous to provide relatively small receptacles 11, which may facilitate transporting them to and installing them on the roof 5. Fig. 4 shows a schematic front view of a building 3 with a growing medium 4 for a green roof on the roof 5 of the building 3. The roof 5 is provided at an angle with respect to a horizontal plane, in the shown example being the ground on which the building 3 is provided. During construction of the green roof on top of the roof 5, a layer of growing suspension has been provided that resulted in a growing medium 4 having a substantially constant thickness on the roof 5. On top of the growing medium 4, vegetation 13 has been provided.

[0043] The invention is by no means limited to the embodiments shown and described herein. Many amendments can be made within the concept of the disclosure, including combinations of some or all of the features of the methods and structures as disclosed. For example, the containers and / or covers can be made of different materials, whereas they can also be made using different techniques, such as for example rotation molding, compression molding or vacuum forming. Holding elements can be provided for differently, for example as spaced apart elements. The covers can moreover be formed differently, for example closed, without openings.

[0044] These and other such alternatives are considered to fall within the scope of the appending claims.

Claims

Claims1. Method of providing a growing medium for a green roof on a roof of a building, comprising the steps of:- mixing mineral wool and a solvent to form a growing suspension;- providing the growing suspension on a roof of the building; and- letting the growing suspension rest on the roof of the building such that the mineral wool settles on the roof.

2. Method of providing a growing medium for a green roof according to claim 1, wherein the method further comprises the step of:- draining the solvent from the growing suspension when the growing suspension is resting on the roof of the building.

3. Method according to claim 1 or 2, wherein a porous material is added to the mineral wool and the solvent during mixing to form the growing suspension, and the porous material settles on the roof when the growing suspension rests on the roof.

4. Method according to claim 3, wherein the mineral wool and porous material of the growing suspension are homogenously distributed in the solvent.

5. Method according to any of the preceding claims, wherein the solvent is water and I or the mineral wool is stone wool.

6. Method according to any of the claims 3-5, wherein the porous material is a porous lava stone material.

7. Method according to any of the preceding claims, wherein the solvent additionally comprises a substance for promoting the growth of vegetation.

8. Method according to any of the preceding claims, further comprising the steps of:- mounting a receptacle on the roof of a building, wherein said receptacle comprises an opening, wherein said opening is arranged to receive the growing suspension; and- providing the growing suspension in the receptacle.

9. Method according to claim 8, wherein the growing suspension is provided in the receptacle before the receptacle is mounted on the roof of the building.

10. Method according to any of the preceding claims, further comprising the steps of:- providing deposition means having an inlet for receiving growing suspension, an outlet nozzle, and a pump arranged to drive growing suspension from the inlet to the outlet nozzle during use;- feeding growing suspension to the deposition means such that the deposition means transport the growing suspension from the inlet to the roof of a building via the pump and outlet nozzle.

11. Method according to any of the preceding claims, wherein the roof of the building is inclined with respect to a horizontal plane, wherein the roof preferably forms an angle between 15 and 75 degrees with respect to the horizontal plane.

12. Growing suspension for a green roof on a roof of a building, wherein the growing suspension comprises mineral wool, porous material, preferably lava stone, and a solvent, wherein the volume-ratio of lava stone to mineral wool is between 1:20 and 10:7, preferably between 1:10 and 3:1, more preferably between 1:2 and 3:5, and most preferably 1:1.

13. Growing suspension according to claim 12, further comprising at least one of compost, biochar, perlite, vermiculite, coconut coir, expanded clay aggregates, peat moss, worm castings and zeolite.

14. Building comprising a roof and a layer of growing suspension according to claim 12 or 13 on the roof, wherein said layer of growing suspension has substantially the same thickness.

14. Building comprising a roof according to claim 13, wherein the roof is provided at an angle with respect to a horizontal plane, preferably at an angle between 15 and 75 degrees with respect to the horizontal plane.

15. Building comprising a green roof according to claim 13 or 14, wherein said growing medium is provided using the method according to any one of claims 1-10.

16. Method of producing a reinforced vegetation mat for green roofs, said method comprising the steps of:- providing the growing suspension according to any of the claims 12 or 13;- providing a vegetation mat on the growing suspension- rolling up the vegetation mat and the growing suspension once the vegetation mat has been attached to the growing suspension.

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