RSS Link Follow me Facebook Email

Home Improvement

How to Replace Exterior Garage Door Trim1

Have you ever bought a new house, moved into your palace, and immediately discovered defects?  Standard operating procedure is to note the problems on a punch list and have the builder fix them during the first year.  Good enough, but what happens when the defect is discovered ten years later?  You fix it yourself! 

The wooden garage doorway trim on our house touched the concrete pad where rain gathered–for ten years.  The water wicked up the wood grain, repeatedly soaking the trim until it rotted.  Caught soon enough, the trim might have been shortened .25 inch with a side saw to raise the porous end above the concrete.  We were too late.  Now we are replacing all the wooden trim with synthetic material:  reversible PVC trim board and weather stripping that have both a textured and a smooth side, a bright-white finish that can be painted, and a warranty against rot!


  • 9.25-inch PVC trim board and seal strips
  • stainless steel deck screws
  • square driver bits
  • exterior grade water-based caulking


  • circular saw
  • electric drill/driver
  • hammer
  • pry bar
  • putty knife
  • damp rag

1.  Measure the top and two sides to get trim dimensions before visiting the home improvement store–garage doors come in different heights and widths!  Purchase PVC trim board and weather stripping in the closest length to avoid waste or having to piece them together.

2. Use a pry bar and hammer to loosen and remove the existing trim boards and weather strips at the nails.  Wear protective eye covering and a face mask to avoid inhaling the dust.

3.  Re-measure after the demolition to get more precise lengths.  Do the top trim first.  Transfer the measurements to a trim board and cut it to length.  Fit it in place and check for level, inserting wooden shims between the trim and header if necessary.

4.  Drive stainless steel deck screws through the trim and shims into the garage door header.  Sink the screw heads slightly below the surface.  (These screws heads may require a square driver bit. Stock up on bits because they wear out.)  Our PVC trim had marks for screw spacing.

5. Measure the sides individually, because they may not be identical.  Cut the trim board to length, making it about .25 inch shorter than your measured length.  Rest it temporarily on a shim to lift it off the concrete and butt it squarely against the top trim installed earlier.  Plumb the trim with a level, shimming and securing it with stainless steel deck screws in the same way as the top trim.

6. Repeat Steps 3 through 5 to install the PVC weather stripping, starting with the top so the moving garage door slides against it rather than the side pieces.  The sweep on the stripping will face the garage door.

7. Fill the nail holes and corner joints with exterior grade water-based caulking.   A putty knife and damp rag make neat work.

text and photos by Sandra Simmons

Share and Enjoy:
  • Print
  • Digg
  • Sphinn
  • Facebook
  • Mixx
  • Google Bookmarks
  • Reddit
  • RSS
  • Twitter

Comments / Discussion

  1. Mike
    Good advice very poorly documented article. I may be a little exagerated by stating look here heart surgery in a 3 step pictorial. Many people have no idea the importance of a speed square or even what such a tool is. How about using the old pieces as templates to cut new.
    December 2, 2010 at 10:28 am | Permalink
Get our Email Newsletter

Want to receive our email newsletter?


Page optimized by WP Minify WordPress Plugin