Many flat roofs have something sticking through them, such as a soil vent pipe, a rooflight, an extractor outlet or a chimney. These penetrations are possible with EPDM, but each one is a spot that needs careful work.
How penetrations are sealed
Pipes are usually sealed with pre-formed collars or boots that fit over the pipe and are bonded to the membrane. Rooflights have a kerb or upstand around them, and the membrane is turned up the kerb and finished neatly. Outlets and vents have purpose-made fittings. When done properly, these details can be watertight for a long time.
Why fewer is easier
A simple roof with one or two penetrations suits EPDM well. A roof with many pipes, vents and awkward shapes needs more cuts and more sealing, and each adds some risk. It is still possible, but it takes more time and skill.
Where the details are
Check how the roofer proposes to seal each penetration, and where the rooflight kerbs will be. If an old rooflight is poorly fitted or the kerb is damaged, it may be best to replace or rebuild it at the same time.
Alternatives
On a roof with a lot of complex details, GRP is sometimes chosen because it can be moulded around awkward shapes. See our Flat Roofing section for the options. We look at the actual roof before recommending a covering.
Access for maintenance
If service equipment such as an extractor or aerial needs regular access, protective walkways stop people damaging the membrane.
Planning ahead
If you intend to add a rooflight or vent later, mention it now, so the roof can be detailed for it.
See our EPDM Rubber Roofing section or call 07766 547309.
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