Pile Door Bottom Seal: Sealing the Gap Under the Door
An under-door gap of 8 mm looks harmless on a drawing. In service it is a permanent opening: cold air in winter, warm air in summer, dust, corridor noise, and a line of light across the floor. On exterior and balcony doors it also admits wind-driven mist and insects. A door bottom seal strip closes that opening without altering the door leaf or frame. It is usually a straightforward, practical component in the whole weatherseal assembly — provided the profile is sized to the actual gap, not to a nominal one.
What the Under-Door Gap Actually Does
The gap under a door is rarely constant. Hinges settle, floors are not perfectly level, and a sliding panel changes clearance along its travel. Clearances vary from door to door, so measure the actual gap at several points along the door's travel; carpet can close part of that opening.
That variable opening has four consequences: air infiltration (drafts), particulate entry (dust and pollen), sound transmission (noise), and light bleed. For engineers specifying a door assembly, the under-door gap is often the largest single leakage path remaining after the frame seals, glazing gaskets, and lock hardware are addressed.
How a Pile Door Bottom Seal Strip Works
A pile door bottom seal strip is a dense brush of PP polypropylene yarn held in a narrow base. The three functional properties we state for these profiles are anti-wind, anti-noise, and anti-dust. A plastic fin can be added as a secondary flap; fin height can be the same as, higher than, or lower than the pile, depending on how the profile is used.
We manufacture these profiles from PP yarn. We do not make rubber or EPDM seals, and we do not present them as ours.
Sizing a Door Bottom Seal Strip: Pile Height B Against the Gap
Pile height B is the dimension that determines whether the seal works. Our range is 5–20 mm. Base width runs from 4 mm to 25 mm, and base thickness is 0.8 ± 0.15 mm. Pile width varies by specification (D pile-width codes); base margin (G) varies with base width and pile width.
The practical method is to measure the gap at several points along the door's full travel, take the largest figure that will be crossed, and select a pile height slightly above it so the filaments deflect against the floor rather than hang free. Undersizing leaves a leak. Oversizing is not free either: excessive deflection increases drag, and on a long sliding panel it can fold or curl the yarn over time.
Two of the constraints are mechanical. The base width must match the groove or carrier you have, and the base thickness of 0.8 ± 0.15 mm must suit the slot tolerance. Get those two right and the pile height becomes the only real variable.
Mounting a Door Bottom Seal Strip
There are three common fixing routes, and they suit different situations.
Groove or kerf. A slot is routed into the bottom rail and the base is pushed in. No adhesive, no fasteners, and the profile can be replaced without removing the door. This is the cleanest option on new production.
Adhesive backing. Self-adhesive bases are used for retrofit work. They perform well on clean, dry, flat surfaces and poorly on rough, dusty, or damp ones. If the bottom rail is uneven or the door is regularly wet, expect the tape to be the limiting factor, not the pile.
Screw-on carrier. A carrier is fixed to the door bottom and the pile profile is inserted into it. This is useful where no groove exists and where the seal needs to be removable.
Options across our range include adhesive backing or none, and plastic fin or plain pile. Length is customized to the order.
Silicone Option for Exterior Doors
We supply pile with or without silicone treatment. Exterior doors face higher dust loading and more moisture exposure than interior doors, and silicone treatment — better waterproof effect and anti-aging ingredients (supplier-stated) — is the option for those conditions. It is a finish on the yarn, not a different sealing principle — the sizing and mounting logic do not change. If you are sealing an interior door in a dry environment, non-silicone is normally sufficient.
Choosing the Right Bottom Seal
Start from the measured gap, the floor surface, and whether the door slides. For pile strips, match base width (4–25 mm) to the mounting and pile height (5–20 mm) to the gap; silicone treatment — better waterproof effect and anti-aging ingredients (supplier-stated) — is the option for exterior doors. Confirm the final choice against your own measurements before ordering.
What Our Alibaba Listings Show
Pile door bottom seals appear on our Alibaba listings with an MOQ of 20,000 meters and a price shown at $0.01/m. Listing applications include French patio doors, balcony sliding doors, wooden doors, interior and exterior doors, shower doors, caravan and RV doors, and greenhouses. Those application lists are listing content, not a verified technical specification — treat them as a starting point and confirm the profile against your own drawing.
Production Capacity and Ordering
Supplier-stated figures for our Jiaxing facility are 20+ production lines, 2,000 sqm, and a daily capacity of 300,000 meters. Shipment mix is roughly 50% domestic China, with the balance exported to Africa (15%), South America (10%), South Asia (10%), North America (5%), Eastern Europe (5%), and Southeast Asia (5%).
To quote accurately we need four things: base width, pile height, base thickness or slot tolerance, and the option set (silicone or non-silicone, adhesive backing or none, plastic fin or plain pile). Length is cut to your requirement.
Start with the Pile Weatherstrip Selector to narrow the profile, then send your base width, pile height, and options to [email protected] or +86-573-86779825 for a quote. Full profile data is in our pile weatherstrip range.