GB2571698A - Flat roof systems and methods for constructing flat roof systems - Google Patents
Flat roof systems and methods for constructing flat roof systems Download PDFInfo
- Publication number
- GB2571698A GB2571698A GB1719452.3A GB201719452A GB2571698A GB 2571698 A GB2571698 A GB 2571698A GB 201719452 A GB201719452 A GB 201719452A GB 2571698 A GB2571698 A GB 2571698A
- Authority
- GB
- United Kingdom
- Prior art keywords
- layer
- vapour
- flat roof
- roof system
- breathable
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract 7
- 239000010410 layer Substances 0.000 claims 34
- 239000004794 expanded polystyrene Substances 0.000 claims 3
- 239000007788 liquid Substances 0.000 claims 2
- 239000000463 material Substances 0.000 claims 2
- 229920000642 polymer Polymers 0.000 claims 2
- 239000011241 protective layer Substances 0.000 claims 2
- 238000010521 absorption reaction Methods 0.000 claims 1
- 239000012528 membrane Substances 0.000 claims 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
- E04D3/00—Roof covering by making use of flat or curved slabs or stiff sheets
- E04D3/35—Roofing slabs or stiff sheets comprising two or more layers, e.g. for insulation
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
- E04D3/00—Roof covering by making use of flat or curved slabs or stiff sheets
- E04D3/35—Roofing slabs or stiff sheets comprising two or more layers, e.g. for insulation
- E04D3/351—Roofing slabs or stiff sheets comprising two or more layers, e.g. for insulation at least one of the layers being composed of insulating material, e.g. fibre or foam material
- E04D3/355—Roofing slabs or stiff sheets comprising two or more layers, e.g. for insulation at least one of the layers being composed of insulating material, e.g. fibre or foam material the insulating layers of adjacent slabs having cooperating edges
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
- E04D13/00—Special arrangements or devices in connection with roof coverings; Protection against birds; Roof drainage ; Sky-lights
- E04D13/16—Insulating devices or arrangements in so far as the roof covering is concerned, e.g. characterised by the material or composition of the roof insulating material or its integration in the roof structure
- E04D13/1606—Insulation of the roof covering characterised by its integration in the roof structure
- E04D13/1662—Inverted roofs or exteriorly insulated roofs
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Building Environments (AREA)
Abstract
A flat roof system covers at least a part of the top of a building. The flat roof system comprises a water-impermeable layer formed on top of the building, an insulating layer positioned above the water-impermeable layer, and a vapour-breathable layer positioned above the insulating layer. The vapour-breathable layer prevents water passing from above the vapour-breathable layer into the insulating layer. The vapour-breathable layer further allows water vapour to pass from the insulating layer to above the vapour-breathable layer.
Description
Flat roof systems and methods for constructing flat roof systems
Field of the Invention
The present invention concerns flat roof systems, and methods for constructing flat roof systems.
Background of the Invention
Flat roof systems typically comprise an insulating layer formed for example of expanded polystyrene (EPS), and a waterproof layer to stop rain and the like penetrating the roof and entering the building below.
The waterproof layer may be provided above the insulating layer, in which case the flat roof is known as a conventional roof system. Alternatively, the waterproof layer may be provided below the insulating layer, in which case the flat roof is known as an inverted or protected membrane roof system.
A known inverted roof system 1 is shown in Figure 1. The inverted roof system 1 is positioned on a roof deck 2, which is the upper part of the building upon which the inverted roof is constructed. On top of the deck 2 is a waterproof membrane 3. An insulating layer 4 comprised of multiple interlocking insulation boards 4a is positioned on top of the waterproof membrane 3, and is overlaid by a water-flow reducing protective layer 5. A ballast layer 6, for example of gravel, covers the protective layer 5.
An insulation board 4a of the insulating layer 4 of the inverted roof system 1 is shown in Figure 2. As can be seen, the insulation board comprises two offset flat rectangular sheets, so that adjacent insulation boards 4a will interlock.
-2Thus, the insulated layer 4 is positioned above the waterproof membrane 3, making the roof system 1 an inverted roof. The ballast layer 6 protects and keeps in place the lower layers of the roof system 1, while the protective layer 5 helps prevent rainfall passing through in liquid or vapour form.
Inverted roof systems have many advantages over conventional roof systems.
The presence of the insulating layer above the waterproofing membrane has several advantages: damage to the waterproofing membrane by variations in temperature is reduced, it prevents UV degradation, the waterproofing layer can be easily inspected and tested during construction of the roof, and the building can be weatherproofed more quickly, allowing interior work to begin earlier.
However, a disadvantage of inverted roof systems is that the insulation can get saturated with water, reducing its insulating properties and so meaning a thicker layer of insulation is required.
The present invention seeks to provide a flat roof system that provides the advantages of an inverted roof system, but which avoids or mitigates the abovementioned disadvantages. Alternatively and/or additionally, the present invention seeks to provide improved flat roof systems and improved methods for constructing flat roof systems.
Summary of the Invention
In accordance with a first aspect of the invention there is provided a flat roof system covering at least a part of the top of a building, the flat roof system comprising: a water-impermeable layer formed on top of the building;
an insulating layer positioned above the water-impermeable layer; and a vapour-breathable layer positioned above the insulating layer;
-3wherein the vapour-breathable layer prevents water passing from above the vapour-breathable layer into the insulating layer;
and wherein the vapour-breathable layer further allows water vapour to pass from the insulating layer to above the vapour-breathable layer.
By having the different layers of the flat roof system with different functions, an advantageous flat roof system is provided. The water-impermeable layer protects the top of the building from the ingress of water, for example rain. The insulating layer then provides insulation to prevent heat escaping from the building through the flat roof system, and also advantageously provides additional protection for the waterimpermeable layer. The vapour-breathable layer then allows water present within the flat roof system to escape. Such water may be present from the construction of the inverted roof system, for example if construction occurred in wet conditions (e.g. rain), or may enter the flat roof system after construction. Allowing such water to escape prevents the disadvantageous effect it would otherwise have on the insulating properties of the insulating layer, so providing a flat roof system with improved insulating properties and/or a flat roof system in which a thinner insulating layer can be provided to provide the same insulating properties as given by conventional flat roof systems.
Preferably, the flat roof system is an inverted roof system. Preferably the insulating layer is positioned directly on, i.e. immediately above, the water-impermeable layer. Preferably the vapour-breathable layer is positioned directly on, i.e. immediately above, the insulating layer.
The vapour-breathable layer may be a high performance membrane with high wet strength, high water resistance and high water vapour permeability. The vapourbreathable layer may be formed of polypropylene. The vapour-breathable layer may be formed of a non-woven, spun-bonded polypropylene material.
Advantageously, the vapour-breathable layer allows water vapour to pass from the insulating layer to above the vapour-breathable layer. Preferably, the vapour
-4breathable layer is impermeable to liquid water. The vapour-breathable layer may be water-impermeable in either or both directions. Where the vapour-breathable layer is impermeable to water passing from above into the insulating layer, this advantageously prevents the ingress of water into the insulating layer, and generally provides an additional layer of protection from water. Advantageously, the vapour-breathable layer comprises a plurality of bonded sheets of vapour-breathable material. By bonding sheets of vapour-breathable material together, a continuous vapour-breathable layer is provided across the top of the building or part thereof, with no gaps through which water could pass into the insulating layer. The sheets may be bonded by gluing, heatsealing, or in any other suitable way.
Preferably, the insulating layer is formed of an insulating polymer. In this case, preferably the insulating polymer is expanded polystyrene. The expanded polystyrene may be low-water absorption expanded polystyrene. Preferably, the board is made from beads of low-water absorption expanded polystyrene for use in inverted roofs. Alternatively, the insulating panels may be formed of any material from the group of extruded polystyrene, polyurethane or polyisocyanurate. The material may have a thermal conductivity of 0.050W/mK or below. The material may have a thermal conductivity of 0.040W/mK or below. Preferably, the material has a thermal conductivity of 0.036W/mK or below. Advantageously, the material has a thermal conductivity of 0.031W/mK or below. The material may have a thermal conductivity of 0.021W/mK or below. It will be appreciated that other suitable insulating materials could be used.
Preferably, the insulating layer comprises a plurality of insulating blocks. In this case, preferably at least one edge of the insulating blocks comprises a joint. The joint may comprise an extended portion for positioning with a corresponding recess in an adjacent insulating block. Alternatively and/or additionally, the joint may comprise a recess for receiving an extended portion of an adjacent insulating block.
-5Preferably, the water-impermeable layer is a melted liquid membrane. In this case, the membrane may be applied directly to the top of the building roof structure. However, it will be appreciated that other typed of water-impermeable layer could be used.
The flat roof system may further comprise a protective layer positioned above the vapour-breathable layer. Preferably, the flat roof system further comprises a ballast layer positioned above the vapour-breathable layer.
In accordance with a second aspect of the invention there is provided a method of constructing a flat roof system as described above on the top of a building, comprising the steps of:
forming a water-impermeable layer on top of the building;
providing an insulating layer above the water-impermeable layer; and providing a vapour-breathable layer above the insulating layer.
Advantageously, the step of providing the vapour-breathable layer comprises forming the vapour-breathable layer by bonding together a plurality of sheets of vapour-breathable material.
Preferably, the step of providing the insulating layer comprises forming the insulating layer from a plurality of insulating blocks.
The method may further comprise the step of providing a protective layer above the vapour-breathable layer.
Preferably, the method further comprises the step of providing a ballast layer above the vapour-breathable layer.
It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention.
-6Description of the Drawings
Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which:
Figure 1 shows a known flat roof system;
Figure 2 shows an insulating board of the flat roof system of Figure 1;
Figure 3 shows a flat roof system in accordance with an embodiment of the invention; and
Figure 4 shows a flat roof system in accordance with another embodiment of the invention.
Detailed Description
An inverted roof system in accordance with an embodiment of the invention is now described with reference to Figure 3.
As with the known inverted roof system of Figure 1, the inverted roof system 10 of the present embodiment is positioned on a roof deck 2 which is the upper part of the building upon which the inverted roof system 10 is constructed. On top of the deck 2 is laid the waterproof membrane 3, which in the present embodiment is a melted liquid membrane which is poured/painted onto the roof deck 2, and which cools to form the waterproof membrane 3. Again, an insulating layer 4 comprised of multiple interlocking insulation boards 4a is positioned on top of the waterproof membrane 3. In the present embodiment the insulating boards 4a are 1200mm x 1200mm, though it will be appreciated that in other embodiments boards of other dimensions may be used.
-7In the present embodiment of the invention, a vapour-breathable layer 11 is positioned on top of the insulating layer 4. The vapour-breathable layer 11 is formed of sheets 11a of vapour-breathable material, which are bonded together at bonds lib to form a continuous layer of vapour-breathable material over the insulating layer 4. In the present embodiment the vapour-breathable layer is a non-woven, spun-bonded polypropylene material, with a weight of 100g/m2 and a water vapour resistance of O.OlMNs/g (Mega Newton seconds per gram). However, it will be appreciated that in other embodiments, a vapour-breathable layer with different properties and/or formed of other materials could be used. The bonded sheets together provide a high performance membrane with high wet strength, high water resistance and high water vapour permeability.
A ballast layer 6, for example of gravel, is then laid over the vapour-breathable layer 11.
In this way, the different layers of the inverted roof system 10 each form a different function. The waterproof membrane 3 protects the roof deck 2 and the building generally from the ingress of water, for example rain. The insulating layer 4 then provides insulation to prevent escaping heat, and as discussed above also helps to protect the waterproof membrane 3.
The vapour-breathable layer 11 then has a dual purpose. First, it helps to prevents water entering into the inverted roof system 10, e.g. above, below and between the insulating blocks 4a of the insulating layer 4. It is able to do this as the vapour-breathable sheets 11a of the vapour-breathable layer 11 are bonded together to form a continuous layer over the insulating layer 4, and the material of the vapourbreathable layer 11 is impermeable to water in liquid form, and so prevents the ingress of rain or the like.
However, while the vapour-breathable layer 11 is impermeable to water in liquid form, it is permeable to water vapour. This allows any water that may be present within
-8the inverted roof system 10 to escape. Such water may be present from the construction of the inverted roof system, for example if the materials used were not completely dry, or if the construction occurred during wet conditions, e.g. while it was raining.
By both preventing water entering into the insulating layer 4 of the inverted roof system 10, and in addition allowing any water that is present in the insulating layer 4 to escape, the insulating properties of the insulating layer 4 are improved. (Or rather, the insulating properties are not degraded by the presence of any water.) This allows an inverted roof system with improved insulating properties and/or an inverted roof system with a thinner insulating layer to be provided.
Finally, as the ballast layer 6 is laid over the vapour-breathable layer 11, it can be seen that the vapour-breathable layer 11 also provides a protective layer to protect the insulating layer 4 from damage, for example by the ballast layer 6.
An inverted roof system in accordance with another embodiment of the invention is now described with reference to Figure 4.
Similarly to the previous embodiment, the inverted roof system 20 of the present embodiment comprises a waterproof membrane 3 laid on a roof deck 2, an insulating layer 4 positioned on top of the waterproof membrane 3, and a vapourbreathable layer 11 is positioned on top of the insulating layer 4.
However, in contrast to the previous embodiment, the inverted roof system 20 further comprises a protective layer 5 positioned on top of the vapour-breathable layer 11. The ballast layer 6 is then laid on top of the protective layer 5. The protective layer 5 may be a simple fine plastic mesh or other protective material, and in particular only acts to protect the rest of the inverted roof system 20 from damage, and does not need to prevent the ingress of water or the like. However, it will be appreciated that the protective layer 5 must be permeable to water vapour, so that it does not prevent it
-9escaping from the vapour-breathable layer 11 underneath. In most embodiments, the protective layer 5 will be permeable to water in liquid form as well as water vapour.
While the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. The skilled person will in particular appreciate that the insulating panels could be shaped in various alternative ways while still being in accordance with the invention.
Claims (19)
1. A flat roof system covering at least a part of the top of a building, the flat roof system comprising:
a water-impermeable layer formed on top of the building;
an insulating layer positioned above the water-impermeable layer; and a vapour-breathable layer positioned above the insulating layer;
wherein the vapour-breathable layer prevents water passing from above the vapourbreathable layer into the insulating layer;
and wherein the vapour-breathable layer further allows water vapour to pass from the insulating layer to above the vapour-breathable layer.
2. A flat roof system as claimed in claim 1, wherein the vapour-breathable layer allows water vapour to pass from the insulating layer to above the vapour-breathable layer.
3. A flat roof system as claimed in claim 1 or 2, wherein the vapour-breathable layer is impermeable to liquid water.
4. A flat roof system as claimed in any preceding claim, wherein the vapour-breathable layer comprises a plurality of bonded sheets of vapour-breathable material.
5. A flat roof system as claimed in any preceding claim, wherein the insulating layer is formed of an insulating polymer.
6. A flat roof system as claimed in any claim 5, wherein the insulating polymer is expanded polystyrene.
7. A flat roof system as claimed in claim 6, wherein expanded polystyrene is low-water absorption expanded polystyrene.
8. A flat roof system as claimed in any preceding claim, wherein insulating layer comprises a plurality of insulating blocks.
9. A flat roof system as claimed in claim 8, wherein at least one edge of the insulating blocks comprises a joint.
10. A flat roof system as claimed in claim 9, wherein the joint comprises an extended portion for positioning with a corresponding recess in an adjacent insulating block.
11. A flat roof system as claimed in claim 9 or 10, wherein the joint comprises a recess for receiving an extended portion of an adjacent insulating block.
12. A flat roof system as claimed in any preceding claim, wherein the waterimpermeable layer is a melted liquid membrane.
13. A flat roof system as claimed in any preceding claim, further comprising a protective layer positioned above the vapour-breathable layer.
14. A flat roof system as claimed in any preceding claim, further comprising a ballast layer positioned above the vapour-breathable layer.
15. A method of constructing a flat roof system as claimed in any preceding claims on the top of a building, comprising the steps of:
forming a water-impermeable layer on top of the building;
providing an insulating layer above the water-impermeable layer; and
- 12 providing a vapour-breathable layer above the insulating layer.
16. A method as claimed in claim 15, wherein the step of providing the vapourbreathable layer comprises forming the vapour-breathable layer by bonding together a
5 plurality of sheets of vapour-breathable material.
17. A method as claimed in claim 15 or 16, wherein the step of providing the insulating layer comprises forming the insulating layer from a plurality of insulating blocks.
10
18. A method as claimed in any of claims 15 to 17, further comprising the step of providing a protective layer above the vapour-breathable layer.
19. A method as claimed in any of claims 15 to 18, further comprising the step of providing a ballast layer above the vapour-breathable layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1719452.3A GB2571698A (en) | 2017-11-23 | 2017-11-23 | Flat roof systems and methods for constructing flat roof systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1719452.3A GB2571698A (en) | 2017-11-23 | 2017-11-23 | Flat roof systems and methods for constructing flat roof systems |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201719452D0 GB201719452D0 (en) | 2018-01-10 |
| GB2571698A true GB2571698A (en) | 2019-09-11 |
Family
ID=60950486
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1719452.3A Withdrawn GB2571698A (en) | 2017-11-23 | 2017-11-23 | Flat roof systems and methods for constructing flat roof systems |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2571698A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE29715790U1 (en) * | 1997-09-03 | 1997-10-23 | Basf Ag, 67063 Ludwigshafen | Inverted roof |
| EP1529895A1 (en) * | 2003-10-27 | 2005-05-11 | SILCART S.r.l. | Panel particularly for insulating a loft slab |
| EP2085415A1 (en) * | 2008-01-28 | 2009-08-05 | Karl Nestler | Composite system, method for its manufacture and multi-layered non-woven fabric |
| GB2503891A (en) * | 2012-07-10 | 2014-01-15 | Jablite Ltd | Inverted roof systems |
-
2017
- 2017-11-23 GB GB1719452.3A patent/GB2571698A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE29715790U1 (en) * | 1997-09-03 | 1997-10-23 | Basf Ag, 67063 Ludwigshafen | Inverted roof |
| EP1529895A1 (en) * | 2003-10-27 | 2005-05-11 | SILCART S.r.l. | Panel particularly for insulating a loft slab |
| EP2085415A1 (en) * | 2008-01-28 | 2009-08-05 | Karl Nestler | Composite system, method for its manufacture and multi-layered non-woven fabric |
| GB2503891A (en) * | 2012-07-10 | 2014-01-15 | Jablite Ltd | Inverted roof systems |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201719452D0 (en) | 2018-01-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |