Methodology Waterproofing Flat Boarded Roofs

Boards laid to minimum falls of 1 in 60, the strength and thickness as per engineers specification. The moisture content is not to exceed 7% prior to torch-on applications.

Should light weight screeds be employed an additional sand cement screed is to be placed on top of the light weight screed, the strength and thickness as per engineers specification. Under no circumstances must the torchon material be applied directly onto the light weight screeds.

Special care must be given to all expansion/construction joints, refer to your a.b.e.^® Technical Representative concerned for specific details.

1. New Areas

Prime all surfaces with bitu.prime, including all verges, and around outlets and protrusions and allow the solvent to flash off. Extremely porous surfaces should be re-primed.

2. Rejuvenation
Strip existing waterproofing before priming all surfaces with bitu.prime, including all verges, around outlets and protrusions and allow the solvent to flash off. Some existing waterproofing materials may be overlaid only in consultation with the a.b.e.^® Technical Representative concerned.

• bitu.prime
• abedex^® unigum 4 mm or abedex unigum Mineral Slate 4.5 kg/m2
• abedex^® FS-R 4 mm
• silvakote
• 5 ply malthoid

Apply 5 ply malthoid providing for 100 mm side laps and end laps. The mechanical fasteners anchoring the 5 ply malthoid is to be spaced at intervals of 300 mm centres and shall be fixed incorporating 40 mm diameter washers.

All corners to have a gusset fitted, 100 x 100 mm, apply abedex^® FS-R 4 mm prior to the waterproofing application. A minimum height of 100 mm up the parapet, brought down across at least 100 mm over the 5 ply malthoid.

Apply a second layer of abedex^® unigum 4 mm or abedex^® Mineral Slate 4.5 kg/m2 ensuring that the second layer is fully bonded by means of ‘torchon fusion’ using propane gas, having side and end laps of 100 mm and 150 mm respectively. A minimum of 150 mm sould protrude above finished ground level.

The rolls are to run parallel to each other, centrally staggered to prevent joints overlapping.

See data sheet ‘Six Golden Rules’.

Additional gusset sections of 150 mm minimum up the parapet wall and dressed 150 mm minimum over the main waterproofing, abedex^® unigum or abedex^® unigum Mineral Slate.

Counter flashing over the balance of the parapet is recommended using super laycryl or super laykold incorporating abe.^® membrane, details as recommended in our data sheet. Ensure the lap over the torched membrane is at least 150 mm.

All plain exposed surfaces are to treated with 2 coats of silvakote as protection layer against UV rays. The coating should be applied 6 to 8 weeks after torching process to allow the surface to oxidise slightly thus providing good adhesion of the coating.

Specific attention must be given to the detail work when waterproofing the outlets to prevent ingress of moisture.

abedex^® waterproofing membranes shall only be installed by contractors accredited by a.b.e.^®.

Care must always be taken when working with open flames, potential fire hazard, and molten bitumen from the process, employ safety equipment and clothing where necessary.

All the products are to be applied in accordance with the manufacturers instructions.

All relevant data sheets are to be carefully read for additional information

This data sheet is issued as a guide to the use of the product(s) concerned.

Whilst a.b.e.^® endeavours to ensure that any advice, recommendation, specification or information is accurate and correct, the company cannot – because a.b.e.^® has no direct or continuous control over where and how a.b.e.^®’s products are applied.