ABL (STEVENS) Resin & Glass

Unit 4, Millbuck Way, Springvale Ind Est, Sandbach, Cheshire CW11 3HT, Tel/Fax: 01270 766685/529111

 ROOF SHEATHING

 The following sheets explain the procedures necessary to weatherproof a flat roof using chopped strand mat and resin.

 This procedure is fast becoming the popular alternative to bitumen & hot tar, is very much easier to apply and has a considerably longer life, 30 years can usually be expected.

 The normal method is to strip the old felt & tar surface and fix ¾” exterior plywood or sterling board to the existing roof trusses (do not use any form of chipboard). If removal of the original felt and tar is not possible then the plywood may be formed over the existing roof, ensuring the new roof has adequate falls in order for good drainage and to alleviate the risk of standing water

 Standard roofs require only one layer of 1½oz/ sq foot Chopped strand mat + one layer of glassfibre tissue + final flowcoat layer. Roofs bearing constant pedestrian traffic require an extra sheathing of 1½oz chopped strand mat. Corundum grit or glass grains can be applied with the final flowcoat layer to produce an anti-slip surface.

 The final flowcoat layer is available ready pigmented white or clear which can be pigmented to a colour of your choice; it also contains a stabiliser to guard against the UV rays of the sun.

 Pre-formed edging trims are available as follows in 3 metre lengths(cut to 1 metre for transporting:
Section A: (A200)a right angle that allows rainwater to drop clear of the walls.
Section B: (B260)a right angle that incorporates a parapet to stop rainwater run-off.
Section C: (C100)simulated lead flashing, driven into brickwork and overlapping section D.
Section D: (D260)angled at 135º from vertical wall to horizontal roof surface.

Sections C & D are used when roof adjoins a brick wall.
Click pictures for larger view.
Prices here

Detailed list of Trims available Here

Fix GRP pre-formed edging sections, these can be nailed or screwed.
Section "B"(B260) is fixed as parapet where it is desired for rainwater NOT to run off, and section "A"(A200) as shown allows run off to drop clear of the wall.

2.

When all edging sections are fixed ensure all loose debris, dust, grease etc is removed ready for the resin and glassfibre application

3.

Roll out and cut all lengths of chopped strand mat (CSM) and glass tissue, ensuring the mat and tissue overlaps the edging section by 2”.

4.

Estimate and decant into a bucket the required amount of resin to wet out one length of CSM. For example if the length measures 3 yards approx 3 kilos (litres) will be required. Catalyst additions can be varied slightly according to the ambient temperature, typically at 20ºC add 2% (60ml to 3 kilos/litres) mix thoroughly.

5.

Spread catalysed resin over complete area to be covered by first length of CSM. Immediately apply length of CSM to the area. Begin rolling with paddle roller to completely wet out the CSM. When wetted CSM becomes almost transparent. If any light patches exist these must be rolled adding extra resin if required.
Whilst still wet apply one layer of glass tissue and roll with paddle roller. Usually enough resin residue should be present to completely wet out the tissue without more being required.

6.

When one length is completely wetted out repeat steps 4 & 5 ensuring each length of CSM overlaps the preceding layer by approx 2 inches. Repeat until complete roof area is covered.

Allow to cure approx 1-2 hours.

7.

To apply the final flowcoat layer, simply catalyse approximately 2 kilos (litres) of flowcoat at a time, spreading with a brush or roller onto the cured laminate at a rate of approx 70g/2½oz per sq foot.
Allow coating to sufficiently cure (approx 2-4 hours) before walking on is attempted.

Ensure rain doesn’t fall onto the surface at any stage of the job.

The finished roof fully weatherproofed measuring 24’ x 8’ was completed from start to finish in 7 hours (2 operators)
Tools and materials were:-
2 brushes 4”
1 paddle roller 3" x ¾"
1 paddle roller 6" x 1½"
1 catalyst dispenser
3 buckets 5ltr
3 buckets 2½ltr
5 ltr acetone
latex disposable gloves
25 kilos laminating resin & catalyst
25 sq yards chopped strand mat & tissue
16 kilos flowcoat & catalyst
Amounts include minimum 10% extra for waste and overlaps.