Q-Lon Door Weatherstripping

Q-Lon is a wood or vinyl strip with a vinyl-covered foam gasket on it. The strip is nailed onto the sides and top of the door frame, so when the door is shut, it closes against the gasket, stopping air from sneaking in around the door.

INSTALLATION:
Level of Difficulty: Medium to Difficult
Tools Needed: Measuring tape, pencil, combination or speed square, back saw or hack saw, sharp utility knife, hammer, stainless steel or galvanized 4D nails, exterior grade caulk and caulk gun.

First, make certain that each piece has a good end to measure from. Usually they don't, so true them up nice and square, using a combination or speed square and utility knife to score the wood at a right angle. Then make your first cut with a Japanese crosscut or backsaw, but any decent crosscut or even a hack saw will do.

Fully install the top piece before starting work on the sides. After measuring the stop-to-stop length along the top of the door, mark the wood strip and again score before cutting it - this time to the finished length. Once the Q-Lon is cut to length, dry fit it to see that it's not too long. Then start the nails in the strip (4d nails are ideal) about every 8", leaving about 1.5" at each end to avoid splitting the wood.

Next apply a thin continuous bead of caulk along the back side.

Then, shut and lock door (important) to determine it's final closed position, and locate the Q-Lon against it such that the V-shaped gasket is 60% compressed (per manufacturer's recommendation). Basically, press it up against the door until the V is totally shut and then back off slightly so it opens just slightly. Tack one end in place (without driving nails all the way home) and then skip along and tack every other or every third nail until the other end is reached.

Open and re-close door to evaluate ease of closure - it shouldn't be hard.

Next, measure from the Q-Lon you just installed, down to the threshold and repeat steps above on the two sides. It's best to carefully cut away a small piece of the gasket at the top end, where it meets the gasket on the horizontally installed top piece. If the threshold is sloped, it's nice to fit the bottom ends of the side pieces to match, though not critical. 

(Note that the placement of the Q-Lon along the side of the door opposite the hinges can easily be installed too tightly against the door, making it difficult to close it.)

Once satisfied with the position, finish nailing. Wipe up any oozing caulk - there shouldn't be much if the bead was really light.

One way to check if the Q-Lon is in the right place is to close a piece of paper between the Q-Lon and the door.  If the paper hangs there without falling, it’s tight enough.  If the paper can be pulled out without ripping it’s not too tight.