How to Seal a Door

How to Seal a Door

There are many reasons why you would want to seal a door, but the main ones are to keep out noise, and to prevent a loss of temperature. We’ve written here about how to properly soundproof a room, but here is a step-by-step guide on how you can seal a door frame, how to seal a door airtight, and how to seal a door gap.

How to Seal a Door Frame

Sealing a door frame consists of first, cleaning the door frame, then removing the old weatherstripping (if it exists) and replacing it with new. After that, a new door sweep will be installed to seal the door at the bottom of the frame. 

Cleaning the Door Frame

The very first thing you’re going to want to do when cleaning the door frame is to check to make sure that all of the hinges are installed correctly and that they’re all screwed in tight. If you have hinges that aren’t tight, then you might actually have perfectly fine weatherstripping, but it can’t do its job because the door is not closing properly, So get out a screwdriver or a screw gun, and tighten all the hinges on the door. It’s generally easiest to start with the hinge at the top of the door and work your way down.

In the event that a screw won’t tighten it may be that the existing screw either has a stripped head (meaning the screwdriver can get purchase on the head to turn it properly) or the interior of the screw hole is damaged. In this case, you’ll need to remove the hinge completely and install wood plugs into the hole, and then redrill a new hole for the new screw.

Now that the screws are all tight, check the door to see if that has fixed the problem: does the door swing closed and shut tightly against the existing weatherstripping, or does the weatherstripping need to be replaced? If it does fix the problem then congratulations! You’ve figured out how to seal a door the easiest way possible! But if it doesn’t seal the door, then read on.

Remove old weatherstripping that is broken or deteriorating. Because weatherstripping is generally made from rubber, it lasts many years but will eventually begin to crack and become ineffective. If the weatherstripping has been installed simply by adhesive, you should be able to pull it off, maybe making use of a putty knife to help clean the old stuff away. If the weather stripping has been screwed or stapled into place, then you’ll need to unscrew it or pry the staples loose with a screwdriver or claw hammer.  Once the weatherstripping is removed, scrape the entire surface with a putty knife or paint scraper to make sure that the area is clean. Finally, wipe a damp rag along the door frame to make sure it is all clean of debris. 

Buying the Replacement Parts for Sealing a Door

You’re going to need to get new weather stripping. There are many different kinds available so if you’re not sure which to buy, ask a product specialist at Trademark Hardware what kind you’ll need for how to seal a door. Generally speaking, you’re going to want a wrapped foam weatherstripping, though there are other options.

You’ll also want to buy a door sweep with a flexible vinyl flap. Note that if the door you wish to seal is going to open onto carpet, then a door sweep with a flexible vinyl flap is not the best option--those work best on wooden floors or tile and stone. If the door you’re sealing opens onto carpet you’ll want to get a flexible bulb weatherstripping that is attached to the door’s threshold, so that instead of moving with the opening door, the door closes tightly against the threshold.

Installing the Weatherstripping and Door Sweep

When you get home with your purchases, you’ll want to remove your door entirely from its hinges and take it down from the doorframe. This will help you install the weatherstripping, but you’re also going to need to be able to drill into the bottom of the door to install the door sweep.

Measure the door’s perimeter with a tape measure. To make sure that you are getting an airtight seal you’re going to need the weatherstripping to be cut in as accurate dimensions as possible. 

Once the measurements of the perimeter of the door are made, then mark those measurements on the roll of weatherstripping and make precision cuts (this can generally just be done with a good utility knife, but even a good pair of heavy-duty scissors can do the trick). (If you have bought a different kind of weatherstripping that has a wood or metal backing, then you’ll need a hacksaw for this.) Make sure that your cuts are as precise as possible so you can make an airtight seal on your door.

When you have all sides of the door cut into the right length (top and both sides) then hold it in place and begin tacking it in loosely. This is a place where it can be useful to have an extra helper to give you an extra set of hands, keeping the weatherstripping in place while you tack it in--this is especially useful across the top of the door frame. Then, once tacked into place, you can hammer larger nails into the weather striping to hold it into place. 1-½ inch nails every 12 inches should be the perfect fit.

Installing the Door Sweep

There are many different kinds of door sweeps, and while some don’t require you removing the door entirely from it’s hinges to screw up into the bottom of the door, it’s often easier to do it this way. Regardless of whether you are screwing into the bottom of the door, or the underside of the door, you’ll want to measure the door sweep to perfect length, and then cut through the metal with a hacksaw. The door sweep should already have pre-drilled holes, so you can simply hold it in place and then screw it in tightly. 

Testing the Seal

Want to know how to seal a door? Now you’ve learned! Test the door open and closed. Feel for any drafts that are coming through the door, and, at night, have someone go outside with a flashlight and shine in at the gaps to see if any light is coming in past the weatherstripping--this will give you an idea of where you might need to fix something. 

Choose from our large variety of high quality, durable door seals.