Lead alternative WÜTOP^® FormFlash

Measure the depth of flashing required and add 25 mm to allow for grooves and for minimal overlap with other watertight parts, such as bitumen coverings, slate roof coverings or tiles etc. This determines the width of the roll that should be ordered.

Measure the lengths of the surfaces that need to be covered to determine the required number of rolls. Make sure to take into account an overlap of 100 mm. Ensure that the lead fixing clips are suitable for all weather conditions.

Rolls are supplied in lengths of five metres. Please note: WÜTOP FormFlash can be handled in maximum lengths of 1.5 metres. Please note that the 400 mm FormFlash fixing clips must be used along the entire length of the flashing. FormFlash clips are supplied in bags of 25. One bag is sufficient for a single roll of WÜTOP FormFlash.

Ensure that a bitumen sealant (art. no. 0890 103) is used. Each tube is sufficient for around ten linear metres with a 6-mm bead.

Flashings for a flat roof

All sealing layers are specially designed to prevent rainwater entering the space between the wall and roof covering. However, they are not resistant to torrential rain that penetrates the masonry and flows along the flashing into the cavity. This is

one of the functions of a gutter. The upper surface of the flashing must be finished using a mortar joint or pre-slotted groove so that it is at least 150 mm above the top layer of the roof. The latter must have a cross-section of at least 25 mm x 25 mm. Install the WÜTOP FormFlash in the full depth of the groove, at least 25 mm into the wall. If using a mortar joint, a minimum insertion of 25 mm is required).

WÜTOP FormFlash flashing

Permanently secure the WÜTOP FormFlash in the groove using a stone chisel and FormFlash fixing clips, each placed approximately 400 mm apart above the flashing. Ensure that the clips do not protrude beyond the wall. Finish the groove or seal using bitumen sealant (art. no. 0890 103) in accordance with the instructions on the packaging.

Stepped flashings

This type of flashing is prepared and secured in the same way as for flat roofs, but with an extra minimum clearance of 150 mm to cover the tiles. This means that a wider roll is required. When flashing tiles with a deep profile (or in locations that are highly exposed and when installing on pitched roof sections with an angle of less than 25 degrees), it may be necessary to increase the cover over the tiles to 200 mm. In all cases, the loose edges of the FormFlash must be securely clamped as a precaution against the effects of wind on site.

Tools and equipment

WÜTOP FormFlash can be installed using the same tools as are used for installing lead. You will also need a sharp knife and/or sheet metal shears. In addition, you will need a spirit level, a chalk line and a tape measure.