Tips for Preventing Warping of Exterior Doors Tips for Preventing Warping of Exterior Doors

What You'll Need
Varathane or Polyurethane sealant
Screwdriver
Paint brush
Paint remover or heat gunand a sander (if the door is painted)
Pain (if required)
Sandpaper

Solid wood makes great exterior doors but in some conditions they are prone to warping. Wood expands and contracts with changes in temperature and air humidity, which can lead to twisting, cracking and warping.

If your door is located where it is exposed to the environment, fluctuating temperatures or wetness, and you don’t have the finances or time to replace it, here is how to protect it from warping. 

Step 1 – Remove the Door

On a mild to warm day, remove the door from the door frame with the screwdriver, then remove the hinges from the door. Place it on a table or the floor. Rub or blow off any dust.

Step 2 – Bring the Door Back to Natural

If the door is painted, remove the paint with paint remover and heat gun. If the door is raw wood, smooth and fill any small cracks, then sand if it has been coated to remove any coating or varnish. 

Step 2 – Seal the Wood

Give the whole door a coat of polyurethane or Varathane sealant, including all edges. Wait to dry. The drying time for your particular sealant will be printed on the can. When the door is completely dry, give another coat, and repeat once more until the door has had three coats. No spots on the door must be missed, check that you have sealed the hinge areas, bottom and top of the door.

If you want to repaint the door, wait till the sealant is fully dry then repaint. 

Step 3 – Rehang the Door

Reattach the hinges and rehang the door onto the frame. If the door sticks, you will have to adjust the door jam and sill. untill the door hangs freely. If the door frame is wood, seal it as you did with the door. It is not much good if you seal the door and the frame expands and contracts with moisture, sticking the door.

Tips to Prevent Exterior Doors from Warping

  • Tall doors are more prone to twisting so make sure they are well sealed. Tall doors must be made from hard wood such as oak.
  • Don’t adjust a door or frame in hot or cold weather, it may reset itself when the weather becomes milder and undo your adjustment.
  • If your door is exposed to direct sunlight or the weather, consider building a cover or eave over the doorway. This will also protect people who stand at your door in rough weather.
  • Repair or repaint the door as soon as it shows even small cracks or paint peeling. Polishing the door twice a year can help keep the sealing in good condition.
  • Consider replacing the door with a fibreglass door in humid areas. These often have a faux wood finish.
  • Recoat with Polyurethane or Varathane sealant every two years.
  • Choose a wood known to be weather resistant. Some woods like oak are more weather resistant than others.

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