How to Fix Bubbling Siding

Bubbling or blistering occurs when paint starts to separate from the underlying surface, such as wood siding.


Bubbling has two primary causes: excessive exposure to heat and excessive exposure to moisture. Heat-related bubbles tend to occur when the temperature rises after you apply the paint. Moisture-related bubbling occurs when water gets into the siding. Solving the problem of bubbling may involve nothing more than repainting the area. In some cases, however, you may need to stop a long-term moisture problem.

Step 1

Use a scraper to remove the bubbling paint from the affected area.

Step 2

Sand the area with sandpaper until it has a smooth finish.

Step 3

Apply a coat of primer over the area with a brush.

Step 4

Wait until the primer dries, which might take a few hours or up to 24 hours depending on the environmental conditions in your area.

Step 5

Brush on a matching coat of paint on the area. Avoid applying paint to an exterior wall when the wall is exposed to strong sunlight.

Permanent Fix

Step 1

Check for any areas where water might leak into the wood siding, such as poorly caulked window sills or frames. Apply a new bead of caulk around any windows where water might be leaking into the wood.

Step 2

Look for any plumbing leaks around bathrooms and kitchens or in laundry rooms.

Step 3

Check to see if water vapor coming from a humidifier might be causing bubbles.

Step 4

Inspect any metal flashing around doors and windows where moisture might get through. Ensure that the flashing is in good repair. Replace as necessary.

Things You Will Need

  • Scraper
  • Sandpaper
  • Paintbrush
  • Primer
  • Paint
  • Caulk
  • Metal flashing


  • Consider having a professional install a vapor barrier in your wall if none exists. This will prevent water vapor moving from your interior to your siding.
  • Install an exhaust fan, if necessary, to lower your home's humidity.

About the Author

Mark Pendergast has worked as a freelance writer since 2007, focusing on topics such as health, sports and finance. He has worked as a newspaper reporter and librarian and has written for the "Northside Sun" and "Jackpot," among other publications. Pendergast holds a Bachelor of Arts from Millsaps College.