Trowel Mastic

Name: Trowel Mastic

A heavily filled and fibrated bituminous compound that remains soft and pliable once cured for a long time after application to allow for moderate movement.

Features: Cold applied. – Waterproofs, points and seals. – Fibre reinforced. – Flexible. – Trowellable. – Fast drying. – For exterior use.

Application: A multi-purpose, trowel grade material for waterproofing, stopping, bedding, pointing and sealing. Fibre reinforced making it ideal for filling cracks and holes and cures to give a strong and flexible compound. Can be applied to most common roofing surfaces including mastic asphalt, roofing felt, corrugated iron, cast iron, fibre/cement, slates, lead, copper, zinc, concrete and timber. Fibre reinforced making it ideal for filling cracks and holes and cures to give a strong and flexible compound. Perfect for metal guttering and downpipes.

Instructions: Preparation: All surfaces must be structurally sound, clean, dry and free from surface contaminants such as grease, rust and dirt. If necessary, remove any organic growth i.e. lichen, with a fungicidal wash such as Bond It Mould Stop. If the surface is still dusty after cleaning, or covered with weathered bitumen, prime with Bitumen Primer and allow to dry. To assist application in cold weather store the material in a warm room overnight prior to use.
Application: Apply with a steel trowel or putty knife. Do not thin.
Cracks & holes: Force the compound into the crack leaving slightly proud at the centre. For large cracks and holes apply the compound over the area to be treated and embed a closely woven glass fibre membrane into the compound to overlap the crack or hole by approximately 50mm. Allow to dry and then apply a second coat fully covering the reinforcing membrane.
Corrugated iron/fibre cement sheeting: Tighten loose hook bolt and trowel around with TROWEL MASTIC. Remove loose screws then re-bed both screws and washers in TROWEL MASTIC and tighten. Top seal and trowel to a smooth finish. If a sheet is cracked clean, prime and apply a bandage strip of woven glass membrane embedded in TROWEL MASTIC. Allow to dry and then overcoat. Where required use the same technique to seal side and
end laps in corrugated sheeting.
Tiles: Use TROWEL MASTIC to point up butt ends of ridge tiles, fillets and slates.
Lead and zinc: Trowel over cracks and pinholes, where necessary reinforce with a woven glass fibre membrane embedded in TROWEL MASTIC and overcoat.
Felt: Re-adhere loose felt (especially flashings and details) and seal joints with TROWEL MASTIC. Note: this material should only be applied to surfaces that are completely dry and great care should be taken to ensure that when applied to bitumen felt no moisture
is contained within the felt.
Drying Time: Most of the solvent evaporates in 24 hours under average drying conditions, but the coating remains soft for a long time after application.
Cleaning: Clean with paraffin (kerosene) or Bond It White Spirit.

Limitations: Do not use in areas where subsequent solvent contact is likely. Do not use for potable drinking water tanks. Do not apply to damp surfaces. Allow sufficient drying time between coats. Bitumen may bleed through any paints subsequently applied over it. Apply a primer recommended by the paint manufacturer before overpainting.