Brush Seal Kits

A brush seal kit covers the top of the opening and both sides, so your door width and height are not interchangeable. An 8 ft. wide by 10 ft. tall door needs more brush than a 10 ft. wide by 8 ft. tall door, even though both get called "8 by 10." Every kit ships complete with brush and holder in one of three configurations, sized to eight standard openings.

Which configuration you need

The mixed kit exists because most doors are not uniform. Header clearance is usually the biggest gap on a roll-up or coiling door while the sides run tighter, so 3 in. on top and 2 in. down the sides puts the brush where the gap actually is, for less than going 3 in. all the way around.

How much brush each size takes

Because the kit runs across the top and down both jambs, brush length works out to the width plus twice the height. That is why two doors with the same numbers in a different order are not the same order.

Measure the opening the door closes against, not the panel. If you fall between two sizes, order up and trim to fit.

Picking a brush length

The brush has to close the gap with some deflection left over, so the bristles sit under light pressure against the door rather than barely touching. Measure the widest gap along each edge with the door closed. A 2 in. brush covers a modest, consistent gap; step up to 3 in. where the frame has shifted or the track has worn. Too much deflection wears the bristles early, and too little means the seal does nothing.

Where brush seal beats compression seal

A compression seal such as EPDM needs a reasonably flat surface to press against. Brush seal does not, which is what makes it the right answer on roll-up, coiling, and sectional steel doors where the panel is ribbed or the frame is no longer true. It also handles dust and grit better, and it keeps working as a pest and bird barrier when the gap is too irregular for anything else to close. Many buildings run both: EPDM weather seal along the clean straight edges and brush seal wherever the gap is uneven.

Brush seal kits: common questions