Lowery Ltd, a firm of Civil Engineers had several buildings and portable buildings at their base in Reigate in Surrey that required attention.
The main roof was 130sqm and had a uPVC single ply membrane installed onto 11mm osb. It was currently leaking due to membrane shrinkage due to poor installation.
Roof Repair Reigate
In addition there was one small portable building roof (18 sqm) that had a uPVC single ply membrane installed onto 18mm osb. It was currently leaking due to multiple puncture holes and membrane shrinkage due to lack of proper mechanical attachment.
Lastly, there were an additional three larger portable building roofs covered with ageing bitumen based felt installed onto 18mm ply. The felt was old but the roofs were not leaking (yet!).
The approved contractor Advanced Flat Roofing, stripped the large roof of the uPVC membrane and over decked using 11mm roofing grade construction OSB3 to increase the roof structural integrity. The roof was then covered using the Duoply fleece reinforced EPDM roofing system. Duoply was particularly suitable for this application due to its low per sqm weight therefore not impairing the roofs current design.
The smaller portable building was stripped back but with this roof the contractor managed to repair the existing 18mm OSB deck and re-use it. This roof had failed because of the multiple holes (due to the low puncture resistance of the uPVC membrane) and also due to membrane shrinkage on the perimeter of the roof. This allowed water ingress via the edge trims. Nearly all other single ply systems need to be properly mechanically attached onto the roof terminations to prevent membrane shrinkage. This is not the case with DuoPly’s shrink free construction.
The larger portable building roofs were not leaking and the surfaces were in an acceptable enough condition so the contractor chose to over roof using the Duoply membrane. Duoply is a fully bitumen compatible system which means that in certain circumstances the existing felt/asphalt roof can stay in place saving time, money and most importantly land fill.