Choose the profile by the size of the gap with the door or window closed: I (9 × 2 mm) for 1–2 mm, E (9 × 4) for 2–3.5 mm, P (9 × 5.5) for 3–5 mm and D (9 × 6 up to 21 × 15) for 3–12 mm. The strip should be about 20–40% taller than the gap so it is compressed when closed but does not stop the door from latching.
The four letters describe the cross-section
The letter is simply the shape of the foam when you look at the cut end. D is a hollow half-round bulb on a flat base – the most forgiving shape because the hollow collapses evenly. P has a flat tail and a smaller bulb. E is a low strip with two ribs. I is a plain flat strip for very small gaps.
Gap size per profile
| Profile | Popular sizes (width × height, mm) | Gap it suits | Typical use |
|---|---|---|---|
| I | 9 × 2 | 1–2 mm | Thin gaps, cabinets, windows |
| E | 9 × 4 | 2–3.5 mm | Windows, interior doors |
| P | 9 × 5.5 | 3–5 mm | Doors and windows |
| D | 9 × 6 / 12 × 10 / 14 × 12 / 21 × 15 | 3–12 mm | Doors, larger or uneven gaps |
| B | 15 × 8 | 5–7 mm | Wider frames |
Sizes are our popular references for EPDM foam self-adhesive strips; gap ranges are a practical starting point, not a test result.
How to measure the gap
- Close the door or window normally.
- Push a stack of paper or a feeler gauge into the gap at several points – top, middle, bottom, latch side and hinge side.
- Use the largest common value, not the single worst point.
- If the gap varies by more than 3–4 mm along one side, use a D profile, which tolerates variation best.
Colour, backing and packing
EPDM foam strips are usually stocked in black, white, brown, grey and beige, with a self-adhesive tape backing. For retail, buyers often specify 5–10 m rolls on a printed card; for trade, longer rolls or bobbins in cartons. All can be packed under your own label.
Quick questions
Can I use two strips for a big gap?
It is better to choose a taller D profile. Stacked strips peel apart and compress unevenly.
Which profile seals best against noise?
A D profile with enough compression – the hollow bulb closes the gap completely along its length.
Need a seal for this?
Send your section, gap size or a photo of the old seal – Dora replies usually within 2 hours. Door & window seals are available from 10 m.