How do I know if my threshold needs replacing?

If you can see daylight under your closed door, feel drafts, or find water after rain, your threshold seal needs attention. Start with replacing the vinyl insert before replacing the whole threshold.

Can I adjust my existing threshold?

Many thresholds have screws on top that raise or lower the vinyl insert. Turn screws clockwise to raise the insert for a tighter seal.

Threshold Seal

Caulking & Weatherproofing

Door Seals

Budget: $5-$15 (replacement vinyl insert) | Mid-range: $15-$35 (adjustable aluminum threshold) | Premium: $35-$75 (heavy-duty commercial or ADA-compliant)

Threshold Seals: Door Bottom Seals for Drafts, Water & Insects (2026)

Prepared by Lumberama's Building Materials Team

|Last updated May 25, 2026|Sources & methodology

Threshold seals close the gap between the bottom of an exterior door and the floor or sill to block drafts, rain, insects, and dust. Available as adjustable aluminum thresholds with vinyl inserts, under-door seals, and replacement gaskets, they are critical for energy efficiency and weather protection at entry doors.

Key Features

Blocks drafts
water
and insects; Adjustable height aluminum thresholds; Replacement vinyl and rubber gaskets; Under-door sweep and seal combos; Fits standard 36" and 32" doors

Specifications

Types: adjustable threshold

replacement insert

under-door seal | Materials: aluminum with vinyl insert | Widths: 32"

36" standard | Adjustment: screw-up vinyl insert | Gasket: replaceable | Colors: aluminum

bronze

gold

Applications

Exterior entry door sealing; Sliding glass door thresholds; Garage-to-house door sealing; Commercial entrance sealing; ADA-compliant threshold transitions

Installation Overview

For replacement inserts: pull out old gasket, cut new insert to length, press into threshold channel. For new threshold: remove old threshold, cut new to width, position and test door closure, shim to level, screw down, and caulk edges.

Pros & Cons

Pros

✓ Significant energy savings; Blocks water and pest intrusion; Adjustable for perfect seal; Replacement inserts are inexpensive

Cons

✗ Must be properly adjusted to door bottom; Can interfere with door operation if too high; Vinyl gaskets wear out and need replacement; Threshold replacement can be fiddly

Top Brands

M-D Building Products

Frost King

Thermwell

Code Requirements

ADA requires maximum 1/2 inch threshold height with beveled edges. IRC requires weather-resistant exterior door assemblies. Energy codes may require specific air infiltration ratings at door assemblies.

Buying Tips

Start by replacing the vinyl insert before buying a whole new threshold; Adjustable thresholds with screw-up inserts are easiest to fine-tune; Apply a bead of caulk along the threshold edges to prevent water intrusion underneath