Patent Application
20050257491
1. Field of the Invention
This invention relates to an onsite formed insulation system for new and existing roofs and is particularly concerned with a method of insulating a roof.
2. Prior Art
A high amount of flat roof failures are due to the inability of the roof to shed surface water leading to “ponding” which leads to extra weight on the structure and water penetration.
There are numerous forms of laid to fall roof insulation systems on the market. Slabs of insulation are bonded in hot run bitumen. The existing roof surface of most old flat roofs have ponded and sunken areas. When an insulation board is bonded to the roof it will have a void beneath it. If extra bitumen is applied to fill the void it will burn the insulation. Waterproofing membranes are bonded to the insulation and, when they require renewing, it is impossible to remove the membranes without having to renew the entire insulation system.
With the present systems, a large area is needed to store the materials and to keep them dry. The use of hot run bitumen is dangerous.
The object of this invention is to provide a quicker and easier installation that is not so dependent on dry weather conditions.
According to the present invention, there is provided a method of insulating a roof comprising preparing a roof surface; laying a framework consisting of a plurality of first spaced longitudinal members extending substantially parallel to each other and a plurality of second spaced longitudinal members extending substantially parallel to each other and normal to the first longitudinal members on said roof surface; spraying a polyurethane insulation onto the roof surface to bond the framework to said roof surface, curing the insulation, trimming off any excess insulation and securing at least one sheet of rigid material to the framework.
Preferably, the framework further comprises a series of legs which are secured to the longitudinal members at spaced intervals and serve to space the longitudinal members from the roof. The insulation fills the space between the longitudinal members and the roof. The legs are desirably secured to the first of said longitudinal members.
The longitudinal members preferably take the form of channel members which are desirably U-shaped in cross-section, the web of the U being located uppermost when the framework is laid on a roof. The legs may be made of the same material as the channel members.
The roof insulation system according to the invention may be installed on a flat or a sloping roof. If it is desired to convert an existing flat roof to a sloping roof, the supporting legs of the framework will have differing heights to provide a desired inclination or “slope” of the longitudinal members of the framework.
Preferably, the sheet material consists of plywood which is secured to the longitudinal members of the framework by screws or other suitable fixing means. After fitting, the sheet material will normally be covered by a waterproofing membrane such as a layer of felt.
The invention also extends to a roof insulation constructed by the above-described method.
The invention will now be described in detail, by way of example, with reference to the drawings, in which: —
Referring now to the drawings in detail, the sloping roof structure comprises an existing flat roof 1 including a decking 2 supported on a roof structure 3. The roof decking is covered with a felt roofing layer covered with a bitumen roof membrane having a gritted surface 4 which has deteriorated and is sagging in places forming depressions for ponding water. The existing surface 4 is prepared by removing all surface water and then de-gritting the surface which will remove approximately twenty kilogram per square metre and any damage to the surface is repaired. The bitumen roof membrane now acts as a vapour barrier for the new installation.
A series of legs 5 of varying lengths are cut from a lightweight galvanized channel. The lengths of the various legs 5 will depend on the desired inclination or slope of the roof which is to be fitted onto the existing roof 1. A further series of channel members 6 are cut to length from light weight galvanized channel and are of such a length that they can extend over the existing roof 1 at a desired inclination or slope. If necessary, the lengths of metal channel can be joined together by joining strips 10 if the channel members 6 are not long enough to extend over the length of the roof 1.
The legs 5 can now be secured to the channel members 6, at suitably spaced intervals, by means of self-tapping screws. Adjacent channel members 6 are connected to each other by further channel members 7 which serve to hold and join the channel members 6 together to form a supporting framework which is positioned on the roof 1.
Once the framework has been positioned on the roof 1, polyurethane insulation 17 is sprayed onto the surface 4 and expands and rises to the top of the channel members 6 and 7. This insulation will bond the framework 5,6,7 to the existing roof surface 4, preventing any wind up lift. The polyurethane is allowed to cure and is then trimmed level with the channel members 6 and 7 after which a layer of plywood 8 is screwed to the channel members.
The plywood preferably consists of 9 mm W.B.P. exterior grade plywood but other materials may be used if desired.
The existing upstand kerb 19 and tantalised wood fillet 11 can be raised and refitted to the wall and drip battons 12 are fitted to the fascia board 15. It may be necessary to replace an existing fascia board with a new fascia board of increased height to accommodate the increased height of the new roof. Any roof lights (not shown) can also be raised to accommodate the increased height of the new roof decking 8. The insulation system according to the invention is now ready for waterproofing.
A new waterproofing membrane, for example, a layer of felt 14 can be laid on the decking. There is no restriction on the type of waterproofing membrane that can be applied over this type of roof insulation system. These may include lightweight tiles and battens.
When it becomes necessary to strip the waterproofing membrane this can be readily carried out, for example, first thing in the morning when the air is cool, with little or no damage to the plywood decking 8 or polyurethane insulation 17.
Although the installation of the system has been described in respect of an existing flat roof, the roof insulation system of this invention can be used to insulate and seal a sloped roof, for example an asbestos roof. In this case, the legs 5 can be omitted and the framework of channel members 6 and 7 laid directly on the corrugations of the asbestos roof, by first fitting an increased height fascia board 15 to the low point 18. The framework 6 and 7 can be fixed together at ground level in areas of approximately 25 metres and lifted and laid in place and then the system can be carried out as previously described. This will seal in any danger of asbestos spores being airborne again.
The system according to the invention can also be used to create the falls on all types of new structures, concrete metal deck roofs and timber. There are no restrictions as to what roof systems this can be used for. On a new roof the foam will create its own vapour barrier.
The invention is not restricted to the above-described embodiment but modifications and variations may be made without departing from the scope of the invention. For example, the decking need not be made of plywood but could consist of other suitable materials. Further, the framework need not consist of galvanized metal but could be made of a suitable plastics material.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0409581.6 | Apr 2004 | GB | national |
