How To Waterproof A Door: 5 Steps


Ensuring that exterior doors are 100% waterproof is vital, particularly during the wet winter months.

A fully waterproof door will help keep your home dry and warm while also minimizing any damage caused by damp.

There are several methods that you can use to make your door waterproof, if possible use all four of these methods for the best results.

You will need the following waterproofing materials:

  • Weatherstripping
  • A door sweep
  • Door paint
  • Caulk

1. Install Weatherstripping

Sealing gaps between the door and the door frame is one of the most effective way of waterproofing a door.

Weatherstripping is an easy way to seal up gaps around the edge of your door thus preventing water from getting through.

applying weather stripping to a door

To install weatherstripping follow these steps:

  1. Buy self-adhesive weatherstripping.
  2. Peel the back off the first 10cm of stripping.
  3. Press the first 10cm into place at the very bottom of the door frame, it should be placed into the part of the frame that the door closes against.
  4. Peel back more of the stripping and press it all the way up the door frame.
  5. Use scissors to cut it off once you reach the top of the frame.
  6. Repeat this process going across the top and down the other side of the frame.

When you have finished close your door and leave it closed for a few minutes to press the stripping down into place.

2. Fit A Door Sweep

Adding a rubber door sweep to the bottom of your door creates a very effective water-tight seal between your door and the floor.

Even if you only have an imperceptible gap between the door and the floor damp will seep through when the weather is bad.

A rubber door sweep sweeps the floor as the door is closed thus making a barrier between the door and the floor which is very difficult for moisture to get through.

To install your door sweep follow these steps:

  1. Measure the door width and cut the door sweep to fit if needed.
  2. Mark on your door where the screws will go.
  3. Drill pilot holes in the door – make sure that the holes are smaller than the screws or the sweep will not fit securely.
  4. Attach the sweep and ensure it fits and that the door can open and close without any trouble while the sweep creates a tight seal with the floor.
  5. Tighten up the screws and you’re done!

3. Paint The Door

If your door is made of wood then ensuring that it is regularly painted is vital in keeping it waterproof and preventing damp from getting into it.

If damp gets into your door it will begin to rot and will soon need replacing.

A good lick of paint can keep your door looking new while keeping it waterproof for decades.

To paint your door follow these steps:

  1. Remove all fixtures such as door handles, knockers etc.
  2. Sand the old paint 240 grit sandpaper, then wipe it down with white spirit to remove any dust.
  3. First paint the door completely with a paint primer.
  4. Allow the primer 4 hours to dry (some primers may dry quicker).
  5. Paint the door with your paint ensuring that you paint with the grain.
  6. Give the first coat at least 4 hours to dry before applying a second coat.
  7. Allow at least 4 hours for the second coat to dry before reattaching the door fixtures.

4. Caulk The Door Frame

Door frames are usually caulked when installed to prevent moisture from getting in around the frame.

Over time caulk can break down which can allow water to penetrate through.

caulking a door

To recaulk your door follow these steps:

  1. Wait for a dry day with low humidity and a temperature of at least 8°C/46°F.
  2. Remove existing caulk with a sharp knife.
  3. Remove dirt and debris, if there is any damage to the frame repair it before your begin caulking.
  4. Put the caulk in the caulk gun and snip off the end so that it is ready to use.
  5. Place the end of the caulk gun in the corner of the frame at the bottom and start applying the caulk in a long continuous bead all the way up the side.
  6. Use a rag to smooth it over and remove excess caulk.
  7. Repeat this process on all sides of the frame until it is fully caulked.
  8. Leave the caulk for 24 hours to dry.

5. Seal Around Door Windows

Many exterior doors feature small windows such as those shown below:

Over time the sealant around the edge of the glass can break down allowing water to penetrate your home and, if your door is made of wood, causing your door to begin to rot.

This is undesirable.

caulking a door window

However, it is easy to avoid by reapplying window caulk every five years.

To do this follow these steps:

  1. Make sure the weather is right, it should be a dry day with low humidity and a minimum temperature of at least 8°C/46°F. Ensure that the forecast is good for at least 24 hours as it can take a while for caulk to fully dry.
  2. Remove the existing caulk. To do this use a sharp knife to scrape it out, if you are having trouble getting it out you can soften the caulk with an alcohol-soaked rag.
  3. Remove any debris and dirt around the window before applying the caulk.
  4. Put the caulk in the caulk gun and snip off the end so that it is ready to use.
  5. Place the end of the caulk gun in the corner of the window and start applying the caulk in a long continuous bead until the bottom of the window is done.
  6. Use a rag to smooth it over and remove any excess caulk.
  7. Repeat this process on all sides of the window until it is fully caulked.
  8. Leave the caulk for at least 24 hours to fully dry.
  9. If the weather turns for the worse ensure that it is covered with a waterproof sheet.

We hope you found that helpful.

Regular door maintenance using the methods above will keep not just water out but also noise too.

More importantly, keeping your door in good condition will allow it to last a lifetime!

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