door threshold weatherstripping
Door thresholds are crucial for air sealing effectively the bottom of the doors. Typically, they combine with door sweeps and door bottoms, but some have a weatherstrip seal and they do not explicitly require a door bottom or a door sweep. We deal with this kind of thresholds in this page. For other types of door thresholds, combining with door bottoms and door sweeps, see: Door Bottom and Door Sweep Weatherstripping.
It’s possible to use door sweeps without a door threshold, but that’s not an efficient solution. Without a threshold the sweep will easily become too ineffective. To be effective, door sweeps have to contact the edge of a threshold as the door shuts.
Replacement thresholds
Some replacement thresholds are complicated to install and may require cutting off the bottom of the door or other major adjustments and changes, but others are easy to mount. All depends on the type of the existing door, its bottom, and the existing weatherstrips.
Bulb-thresholds
Bulb-thresholds are typically made of aluminum and have a flexible insert at their top (vinyl…) to seal the door from beneath…
They come with different heights and lengths to respond to the needs of different exterior doors and to create a tight seal when the door closes against the insert. This type of threshold is usually easy to install.
These door thresholds can easily accumulate grit and dirt and are prone to wear and tear. Prices are typically moderate.
Frost-break thresholds
Frost-break thresholds are a variation of the bulb-threshold type. They are made from aluminum or other metal, but they also have wood in their interior. Like bulb-thresholds they use a vinyl element to contact the bottom of the door (a typically removable and replaceable strip of vinyl).
Their price is higher than that of bulb-thresholds, and can be more difficult to install, but they are more effective at sealing. They are adjustable...
Adjustable thresholds
Look at the area where the threshold comes into contact with the edge of the doors. If there is a gap, you should fix it, which is easy (or relatively easy) with adjustable thresholds.Adjustable thresholds – like frost-break thresholds - have at their top a replaceable piece of vinyl, which also can be removed.
To get the adjustment, you have to remove the vinyl and look at the adjustors: a set of large screw heads beneath the vinyl strip. Tight (or lose) the screws, to make the adjustable part of the threshold to rise (or to fall). It’s not easy to get it right at first, and you will probably have to make several tries to get the right position.
The exact adjustment is important. The vinyl should contact the edge of the door without creating too much drag (and without leaving any gap).
Thresholds & Door bottoms & Door sweeps
Most of the times thresholds are an element of a larger door air-sealing system: they combine with door bottoms and door sweeps. And some of these combinations produce the best sealing systems for the bottoms of the doors. See: Door Bottom and Door Sweep Weatherstripping
Images credit: Keep Warm Illinois
See also:
Weatherstripping Materials for Doors
Stop and Jamb Door Weatherstripping
Advanced energy-efficient doors
Exterior Door Types
Exterior Door Manufacturers
The Best of Doors