EPDM Seam Repairs

Posted on by mike

This Flat EPDM rubber membrane Roof on plywood was installed in 2001, as a replacement for a previous original rubber membrane on chipboard.
At the age of 12 years some of the seams/laps/joints came apart and caused leaks inside. A local contractor was employed to do some repair work .It is not clear exactly what he did back then, but for some obscure reason he painted a 150mm wide strip of acrylic paint centred over the seams.
At 14 years (now) some of the seams parted again.
Due to the now hard baked paint applied 2 years ago, a simple overlay of the seam with 150mm wide EPDM Cover Tape was not possible.
To repair the seams in the correct manner, the painted strip, and the failed seam/lap had to be cut out and a new strip of EPDM installed, underlapping and overlapping the main EPDM sheet, with the new laps facing down slope.
The images below show the process involved in replacing 54 lineal metres of seams.

hover cursor over image for text, click image for larger version (600×450 pixels)

EPDM Brand, actual importer unclear view over the flat roof to the south west reverse view, to the south east view past the skylights, to the south east view past the ridge, to the south east reverse view back towards the skylights, to the west south east corner, leaking here joint/lap/seam between skylights closer view of a failed seam between the skylights another suspect seam between the skylights this seam had been repaired with Cover Tape, hundreds of air bubbles 5 metre length of EPDM strip in the workshop ready to have seam tape added both sides back on the roof, the back side of the seam is sliced with a knife, the top overlap easily peels off. closer view of failed 3 inch wide seam a 150mm wide strip is cut out and removed, edge primed and the underlap pressed into postition the upper edge is peeled back and cleaned, primed, then eased down onto the seam tape of the new strip of EPDM completed seam repair another seam is cut out and the EPDM removed under lap is stuck down, centre is glued up ready to stick down strip in position, overlap is cleaned and primed ready to fold down into the seam tape same strip completed, looking south east same strip completed, looking south west T junction where the two seams intersect short srip installed in south west corner above first strip two seam between the skylights require replacement the lower seam is cut out and the new strip attached by the seam tape on the underside lower strip, glued up ready to tuck under lower strip tucked under, upper sheet cleaned and primed upper strip tucked under, upper sheet cleaned and primed completed lower strip completed upper strip both strips completed applying seam tape on ridge seam repalcement strip completed ridge strip the ends of the replacement strips and corners of the skylights are coated with Silcoat, upper seam the ends of the replacement strips and corners of the skylights are coated with Silcoat, lower seam view across towards the west central area between the ridge and the skylights, where that bubbled Cover Tape has been cut out and replaced view back towards the east south eastwest corner, Silcoat corner and end patches no more leaks gutter turndown had lifted, only glued to the drip edge. Lifted, cleaned, primed and seam tape installed for better grip. another seam marked out ready for cutting and removal strip is cut and removed lower edge is cleaned, wind causing havoc lower edge primed with seam primer new strip of EPDM is set on lower edge and glued in waiting for seam primer on underside of upper lap to dry lap is folded down and this one is complete, ends coated with Silcoat another view of the last repair on this roof overview of the down slope on the east side of roof Silcoat is applied to the repair end and to vent patch as an added precaution Pipe penetration collar and repair end coated with Silcoat incompatible silicone seal of pipe bracket replaced with rubber sealant another 2nd roof at the rear of the house another 3rd roof at the rear of the house