What is it?
EPDM (ethylene propylene diene monomer) is a synthetic rubber membrane used as a flexible, fully waterproof seal between doors or windows and the structural openings in which they sit.
- 1External Window
- 2EPDM (bonded to boards)
What does it do?
It provides a weathertight seal that can flex and stretch around awkward junctions, preventing wind and rain from passing through the gaps around windows and doors.
It can be fitted into pre-designed grooves in the window or door frame. The EPDM is fitted to the frame before it is put in place, and then once in place the loose membrane is bonded with adhesive to the structural opening.
How to specify
EPDM products will usually be selected by the window manufacturer or contractor. By its material nature, EPDMs cannot usually be non-combustible. Ensure that the product specified is approved by the Building Control Officer.
Other considerations
EPDM needs a clean, sound substrate to bond to. Dust, damp, or an uneven surface at the time of installation can compromise the seal permanently.
Interacting elements
- Cill: EPDM commonly dresses around the cill-to-frame junction
- DPC: EPDM extends the damp-proof line across a junction DPC sheet can't be formed around