GB2081336A - Insulated roof guttering and expansion joint - Google Patents

Abstract

A roof gutter panel comprises upper and lower skins (11, 12) (e.g. of aluminium) and insulation (14) located between the skins. A plurality of panels are located end to end. Expansion gaps (21) are left between some adjacent sections of the upper and lower skins (11, 12). The gaps are bridged by butt straps (20, 22). A further butt strap may be connected below the upper skins (11). The upper skin (11) and butt strap (22) are covered with a U.V. stabilized membrane (17, 23). <IMAGE>

Description

SPECIFICATION Insulated roof guttering This invention relates to insulated roof guttering.

Industrial and Commercial roofs are now required by law to be insulated to avoid heat loss. The insulating of roofs is standard practice among roofing contractors but a problem usually exists with the satisfactory insulating of the gutters on the roofs for carrying away of rainwater.

At present, there are two standard methods of insulating roof gutters and both are carried out on site. These are: 1) A light weight metal soffit is fitted to the approximate gutter profile and insulation is fitted inside this. A heavy gauge steel or aluminium gutter is thereafter fitted on top of the insulation.

2) A heavy gauge steel or aluminium gutter is fitted and then this is covered by insulation board which is protected by bitumen felt.

The disadvantages of the above methods are as follows: A) All the work of insulating the gutters is carried out on site and is therefore subject to adverse weather conditions and the practical difficulties of producing a suitable standard of workmanship.

B) A uniformity of insulation cannot be guaranteed and this may produce "cold spots" and internal condensation.

C) Any damage to the site-insulated gutter (particularly to type No. 2) will allow moisture into the insulation and rot same. Also, the water leak may be very difficult to trace as the damage point may be some distance from the point where the leak shows.

According to one aspect of the present invention there is provided a pre-fabricated roof-gutter panel comprising upper and lower skins contoured to a pre-determined gutter cross section and insulating material located between the skins over the entire contoured area.

Preferably, the panel has a flanged longitudinal edge for fixing to a roof.

According to another aspect of the present invention there is provided a roof gutter formed of a plurality of pre-fabricated roof gutter panels as defined in the preceding two paragraphs in which butt straps are provided to connect longitudinally abutting panels.

Preferably also, an expansion gap is provided in the upper contoured skin by provision of a requisite gap between the abutting top skin panels and a loose butt strap. This is only required where an expansion joint is provided in the building structure.

Preferably also the insulation material is in the form of insulation board cut in lengths and adhered to the lower skin prior to location of the upper skin thereover.

Alternatively, the insulation material is foam insulation introduced into the space between the pre-connected upper and lower skins.

Preferably also the insulation is of a thickness of 36mm to provide a U-Value for the pre-fabricated unit of 0.6 W per "C. This rating can be increased if required by insulating with thicker insulation board.

Preferably also, the skins are formed of aluminium sheets; alternatively colour-coated steel or galvanised steel sheets may be used.

Preferably also, the upper face of the top skin is covered by a waterproof membrane which is totally bonded to this face by a contact adhesive.

Preferably also, the membrane is ultra-violet stabilised.

The present invention will now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a fragmentary perspective view of a pre-fabricated roof-gutter panel according to the invention; Figure 2 is a perspective view: Figure 3 is a sectional view of an expansion joint arrangement; and Figure 4 is a sectional view of the butt strap arrangement.

Referring to the drawings, a pre-fabricated roof gutter panel 10 is formed in lengths of for example 7 metres. This panel includes upper and lower skins 11, 12 which are contoured to the required cross section e.g. for a valley gutter or box shape or the like.

Insulation material 14 is located between the skins.

The insulation material may be in the form of insulation board which is cut to suitable lengths and breadths; for example, one piece may lie along the bed of the gutter with two other pieces along the sides. The board will be cut at the edges at the required angles to provide for exact fitting together in the required cross section. The board is adhered to the lower skin prior to the location of the upper skin thereover.

The skins 11, 12 are for example, of light gauge aluminium.

Longitudinal flanges 15, 16 of the panel 10 may be fixed to steelwork 18 forming the basis of the roof.

These flanges 15, 16 are formed by the inner edges of the upper and lower skins 11, 12 which are both contoured so that the edge strips shut to form the flange.

A protective waterproof membrane 17 is provided on the upper skin 11 of the panel. The coating may be a sheet of ultra-violet stabilised poly-isobutylene which is bonded to the aluminium sheet by a contact adhesive. This is preferably done while the aluminium sheet is still flat, i.e. before it is contoured to the desired cross section.

A roof gutter is formed by mounting a series of panels 10 in end-to-end abutment, but, over a long length, one or more expansion gaps may be required, to coincide with expansion gaps which are allowed in the structure of the building.

Referring to Figure 3, a sectional view shows an expansion joint which allows the unit to expand to coincide with expansion of the building structure.

The upper and lower skins 11, 12 are preferably of aluminium.

A butt strap 20 which is also preferably of aluminium is fitted to the underside of the lower skins 12 which abut.

The insulation board 14 is continuous across the joint.

The upper aluminium skin 11 is so placed that a gap 21 is provided when the lower skins 12 abut.

The waterproof membrane 17 which covers the top skin 11 is fitted up to the edge of the upper skins.

An upper butt strap 22 is provided which covers the gap 21 between the upper skins 11 and protects the insulation 14 from any damage.

The expansion gap 21 and upper butt strap 22 are covered buy a 100mm or 150mm wide U-V stabilised membrane strip 23 which is solvent welded to the waterproof membrane 17 to provide a homogenically sealed joint.

The above arrangement allows for expansion of the upper skin.

A sectional view is shown in Figure 4 of the arrangement where panels 10 are joined together as part of a continuous run.

The ends of panels 10 are placed together in abutting position and a butt strap 20 is located below the join 24 and pop-rivetted to both panels.

With the panels 10 in the same position an upper butt strap 25 is fitted to the underside of the upper skins and pop-rivetted to both panels.

The insulation board 14 is fitted continuously between the skins at these joints and care is taken that a cross joint of insulation does not occur at the same position as a joint of abutting panels.

A 25mm wide crepe strip 26 is placed over the cross joint 24 in order to isolate the insulation 14 from welding solvent.

A 100mm of 150mm wide U.V. stabilised membrane strip 23 covers the joint and is solvent welded to the membrane 17 covering the top skin 11 to provide a homogenically sealed unit.

Thus a fully insulated gutter is fabricated in a factory where the finished item can be tested for water leaks. The method of insulation is by enclosing completely, insulation to the required thickness by two light gauge skins of aluminium. These skins are securely joined at all joints. All end plates, overflow pipes, expansion joints etc. are all fitted with membrane covering and joints around these items welded to provide a homogeneous seam.

An end plate, or stop ends not shown, is provided at the ends of the formed gutter, and may, if required, be insulated; in which case the end plate comprises a pair of side walls between which insulation board is located and a surround closes the gap between the side walls so as to enclose the insulation board.

The advantages of the Composite gutter are as follows: 1. Site insulation of gutters and the attendant problems are dispensed with.

2. Testing for water-tightness of the insulated gutter can be carried out under factory conditions as opposed to site conditions.

3. Any damage to the waterproofing membrane due to negligence or over abuse can be easily identified and simpiy repaired by solvent welding a patch of membrane over the damaged area.

4. The gutter units are of light and yet rigid construction and are lighter than an equivalent uninsulated conventional gutter. The composite gutter units have been tested for loading characteristics and have been found satisfactory to the relevant ioading requirements for roof coverings and roof panellings (i.e. British Standard Code of Practice CP3: Chapter V; Part l; 1967 Clauses 6.2 and 6.5).

5. Due to the lightweight type of construction of the units, it is not necessary to determine water outlet positions or total exact lengths required prior to manufacture. Outlets are fitted after installation and overall lengths trimmed back to exact length on the roof. This flexibility cannot be met by site insulated single skin gutters and heavy remedial costs can occur due to errors in manufacture of the heavier single skin gutters as to length or outlet positions.

6. The expansion characteristic of the composite gutter has different characteristics than the normal steel or aluminium heavier gauge gutter. The latter requires expansion joints to be fitted at regular intervals along the gutter length to allow for expansion of the gutter. These expansion joints take the form of stop end plates adjacent to one another and therefore water flow in the gutter is impeded and water outlet points must be provided around the expansion joint. The expansion of the composite gutter is not passed along the length of the unit but is retained between the fixings along the longitudinal flanges and therefore expansion joints are not necessary, apart from where an expansion joint is provided in the building. This characteristic, together with the design of the expansion joint when fitted, allows free water flow along the full length of the gutter and thus reduces the requirement for water outlet positions together with associated rainwater pipes. etc. and internal drainage within the floor area ofthe building.

Claims (12)

1. A pre-fabricated roof-gutter panel comprising upper and lower skins contoured to a predetermined gutter cross section and insulating material located between the skins over the entire contoured area.

2. A panel as claimed in claim 1 having a flanged longitudinal edge for fixing to a roof.

3. A roof-gutter formed of a plurality of prefabricated roof-gutter panels as claimed in claim 1 or 2, in which butt straps are provided to connect longitudinally abutting panels.

4. A roof-gutter as claimed in claim 3 in an expansion gap is provided in the upper contoured skin by provision of a requisite gap between the abutting top skin panels and a loose butt strap.

5. A panel as claimed in claim 1, in which the insulation material is in the form of insulation board cut in lengths and adhered to the lower skin prior to location of the upper skin thereover.

6. A panel as claimed in claim 1 or 5 in which the insulation material is foam insulation introduced into the space between the pre-connected upper and lower skins.

7. A panel as claimed in any one of claims 1,5 or 6, in which the insulation is of a thickness of 36mm to provide a U-Value for the pre-fabricated unit of 0.6 W per C.

8. A panel as claimed in any one of claims 1,5,6 or 7, in which the skins are formed of aluminium sheets.

9. A panel as claimed in any one of claims 1 or 5 to 8, in which the upper face of the top skin is covered by a waterproof membrane which is totally bonded to this face by a contact adhesive.

10. A panel as claimed in claim 9, in which the membrane is ultra-violet stabilised.

11. A pre-fabricated roof gutter panel substantially as hereinbefore described with reference to the accompanying drawings.

12. A roof gutter substantially as hereinbefore described with reference to the accompanying drawings.