Specifying metal-channel door brush seals for building openings

Specifying Metal-Channel Door Brush Seals for Building Openings

16 October 2026

Metal-channel brush seals use flexible filaments to help reduce dust, draughts and light around moving door gaps. They can be fitted along door bottoms, jambs and headers, with the brush and holder selected to suit the opening and movement.

The filaments can follow corrugated or uneven surfaces while allowing the door to operate. A brush seal is not automatically fire-rated, smoke-rated, watertight or airtight; those claims require evidence for the complete assembly.

What Should Be Measured First?

Record the door type, travel direction and smallest and largest closed gaps, allowing for frame and floor irregularities. Identify the mounting position: header, side jamb, guide, door bottom or sliding-door meeting edge.

For replacement work, check whether only the brush insert needs replacing or whether the holder is also worn, damaged or unsuitable for the new seal.

Which Filament Is the Best Starting Point?

Polypropylene (PP): Low moisture uptake makes it a candidate for damp conditions.

Nylon:Suitable for frequent movement where wear resistance and bend recovery matter; moisture response varies by grade.

PBT: An option where more consistent wet/dry stiffness is required.

For outdoor installations, specify a UV-stabilised grade. Temperature, chemicals, moisture, abrasion and expected door cycles should be reviewed separately because the polymer name alone does not confirm suitability.

How Should Brush Height and Density Be Chosen?

Specifying Metal-Channel Door Brush Seals for Building Openings

Select the exposed trim length together with the holder angle and mounting position, not from the gap measurement alone. Exposed trim means the filament length outside the channel, not the overall height of the assembly.

Check contact and clearance throughout the door’s travel. The brush should maintain light contact where sealing is required without obstructing movement; excessive engagement can increase drag, noise and wear.

Higher density can improve dust and light control but may add friction. Validate the chosen trim and fill on a sample installation, especially for automatic doors.

What Belongs in the Product Specification?

Distinguish the metal channel that retains the filaments from the separate holder or mounting profile that fixes the brush to the door or frame. Confirm whether the order covers replacement brush strips alone or complete brush-and-holder assemblies.

Select materials for each component: aluminium holders offer low weight and a finished appearance, while galvanised or stainless-steel components may suit different corrosion and washdown conditions. Specify the relevant grade and finish rather than assuming all metal profiles perform alike.

Match the holder section, angle and fixing points to the installation. Door bottoms may also require a separate threshold or water-management detail; brush contact alone does not establish watertightness.

Brushcustom manufactures drawing-based metal channel strip brushes and holder assemblies for bulk OEM, project and replacement orders. For enquiries, provide a drawing or marked installation photo, the gap range, door movement and required quantity.

Comments on this guide to Specifying Metal-Channel Door Brush Seals for Building Openings article are welcome.