Self-adhesive flashing

Self-adhesive, aluminium-faced sealing can be used without the need of special tools, saving a great deal of time and effort. Width must be sufficient to overlap adjoining surfaces by at least 25mm, while making sure that the sealing is ‘snug’ into angles and corners. On overlapping glass and other surfaces, avoid forming air pockets in the angle.

In cold weather, it should be warmed to achieve maximum initial tack. Priming of the surfaces to be sealed also assists adhesion and grows stronger with time.

At the top of a glazing bar leave enough flashing to tuck around the bar end to complete the seal.

Very rough-textured surfaces such as pebbledash and rustic brick require an additional seal at the leading edge-such as a knifing grade of bituminous mastic. A major product of this type is Evostik Flashband, made in 9.75m lengths and in widths of from 50mm to 610mm. A primer is available in various quantities.

Application

All surfaces must first be cleaned. Other than for smooth, non-porous surfaces, such as glass and metal, apply the primer, after removal of dust, rust and old putty. The primer dries quickly and the surface can then be treated.

The material is simply cut to length with a pair of scissors. A release paper on the back peels off and the material can be pressed and contoured into place. Warming improves the application properties.

Finishing can be with a cloth pad, roller or square-section piece of wood, first pressuring the strip firmly into any angles of the area to be waterproofed.

Brushing on

Brush-on roofing treatments for flat or pitched roofs, include Evo-Stik Supa-proof, a rich bitumen-content emulsion, which can be used on roofs of concrete, asphalt, cement, corrugated iron, zinc felt, slate or tiles. This is made in four colours-black, tile-red, slate-grey or green.

The technique of use is to brush thoroughly to remove dirt, dust and moss from all cracks.

Fill all large cracks and depressions with a filler paste, made from clean sand mixed to a trowelling consistency, using the emulsion. If reinforcement is needed to bridge the gaps in the roof, to provide a continuous surface, a sandwich of jute, hessian, linen or canvas can be laid be-tween two coats of the product.

It should be applied when weather conditions are suitable for rapid drying.

Do not use in frosty or damp weather or when rain appears imminent.

Apply, with a hand brush or soft broom, a good generous coat. A similar second coat should be applied when the first has dried thoroughly. A coloured finish may be used as the second coat after a first coat of black.

Brushes and brooms should be washed out immediately after use with water. Do not use paraffin or white spirit for cleaning or mixing with the emulsion.

Weatherproof tape

Weatherproof tapes are another way of sealing. The surface must be clean and dry and wiped with a cloth moistened with paraffin or petrol. All traces of the solvent should be allowed to evaporate before applying the tape.

This is pressed firmly on the surface, smoothing down the centre first, and then working outward along the length of tape, ensuring that the edges are firmly bonded and all air is excluded. On sloping surfaces, start at the top and work downwards.

Unroll as you proceed and take care not to stretch the tape, which should be pressed well down into angles, and should overlap joining surfaces by at least 6mm.

Joints are made by placing one piece over another and smoothing down. On sloping surfaces, the upper piece should always be placed over the lower.

This type of sealing does not normally need painting, but paints may be used, provided care is taken to allow the paint to flow on with the minimum of brushing. Avoid painting immediately after or during hot weather.

The compound on the tape can be cleaned from surrounding areas with a rag moistened with paraffin, white spirit or petrol. Avoid splashing the tape with solvent.

In cold weather application is improved by storing in a warm place before use.

10. November 2011 by admin
Categories: Featured, Handyman Tips | Tags: , , , , , , , , , | Comments Off on Self-adhesive flashing

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