Thresholds, door bottoms and door sweeps

Air sealing gaps at the bottom of a door requires materials and procedures different from those for gaps at the other edges.

Types of weatherstrips

Basically it involves three types of weatherstrips, all very effective in sealing out drafts as long as properly chosen and installed.

- thresholds: the metal or wood hump below the bottom of the door, on the floor.
- sweeps: the piece installed at the bottom of the door, to seal the door to the threshold.
- bottoms: a weatherstrip piece, placed on door’s bottom face, interlocking with the threshold.

All these materials come in a huge variety, involving different configurations, properties, materials and prices. The sweeps, for instance, may be made of metal, wood, vinyl, foam-wood, felt-wood, and present a wide variety of configurations, only in part to respond to the types and particulars of doors or thresholds.

Sweeps or door bottoms?

A major alternative, when weatherstripping the bottom of a door is weather to choose a door bottom or a door sweep.

Sweeps are easier to install. But since they hang below the door, they are more prone to drag on the floor and more subject to wear and tear, which causes a lower durability. That’s why door bottoms can be a smarter option, or at least a more durable one. But it also depends largely on the type and quality of the door bottom and the sweep. There are good and bad ones, and different prices.

Thresholds

There are two main types of thresholds:

- metal thresholds with a flexible (vinyl) insert, articulated with the door bottom in order to create a tight seal when the door closes against the insert. This type of threshold is the easiest to install.

- thresholds involving two units: the floor one, and a mating piece on the bottom of the door (the door bottom). These two units should be configured to interlock and to create a tight seal. The effectiveness of this weatherstripping system is excellent, as long as the pieces are properly installed and interlocking properly.

Replacement of thresholds

Wooden thresholds are particularly subject to the damages of wear. If this is your case, there are many types of replacement thresholds, adapted to standard door widths, namely cheap and efficient aluminum thresholds in several colors. If your door measures aren't standard in terms of width, it’s always possible to trim the threshold.

Installation is typically simple: you just need some basic skills, tools (chisel, hammer…), screws and follow the instructions on the package.

Sweeps

Most sweeps fits on the outside of the bottom of the door; they have a section that flips back down when the door is closed, providing a seal against the threshold. The door sweep should be well adapted and mounted to get a snug fit and a superior air sealing.

Many sweeps are attached to the inside of door with screws (or nails). It’s a rather straightforward job.

Door bottoms

There are many configurations of door bottoms, usually made from aluminum or vinyl. Configurations also vary a lot, and should match the configuration and particularities of the threshold. A good door bottom, meeting the threshold properly, is subject to less wear than door sweeps and will have a larger lifespan.