Polymer weatherseals

The letter describes the cross-section shape. D and P have a hollow bulb that compresses softly and suits medium to large gaps; E, I and W are flat or multi-ribbed sections for small gaps; V suits gaps with a bevelled edge; L fits into a corner. Each item's dimensions are in its spec table so you can filter by the actual gap.

Sizes are given as width x height (for example 12 x 10 mm); the height is the part that compresses. A foam seal should compress by roughly one third to one half of its height when the door closes: a 6 mm gap suits a seal about 9 to 12 mm high. Too little compression leaks air; too much makes the door hard to close and the seal loses its recovery sooner.

EPDM stays flexible at low temperatures and resists ozone and UV, so it is widely used on cold store and exterior doors. However, the working temperature range depends on the specific compound and has not been published for these items, so for deep-freeze rooms confirm the temperature limit before ordering.

The EPDM foam items in this category are fixed with adhesive backing. Clean off oil and grease with isopropyl alcohol, let it dry and apply at room temperature; a cold or damp surface weakens adhesion. Do not stretch the seal while applying it, or it will shrink back and leave gaps at the ends within a few days.

EPDM weatherseal is sold by the metre (MTR) with a minimum of 10 metres. For a quotation, send the item codes and total metres to sales@kit.com.vn, adding an allowance for corner cuts.

There are two ways: run the strip continuously round the corner by notching a V in the backing so it folds, or cut each side separately and mitre the ends to meet. Running continuously leaves fewer joints and so fewer leak points. Place any end-to-end joint at the middle of the top edge, not along the bottom where water collects.

Foam seals close the perimeter gap and so reduce sound passing through it, which noticeably improves a door that currently leaks. For rooms with high acoustic targets, however, foam loses resilience after long compression, and the gap at the bottom of the leaf must also be dealt with for the seal to be effective. Choose a size that keeps contact continuous around the leaf with no open section.

Replace them when the seal has taken a permanent set and no longer recovers after the leaf is opened, when the surface cracks or crumbles, or when the adhesive has let go and the seal is peeling away. Remove the old seal and adhesive completely before fitting new, as sticking onto old adhesive gives poor bond.