Hot Topics: Dealing with Garage Door Jamb Rot

Lead Image for Hot Topics: Dealing with Garage Door Jamb Rot

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Lots of people have trouble with rotting door jambs or door sills and need to know best solutions. Some veteran DIYers decide to replace the sill and jambs, but depending on the shape of your door, this can be a tough task. Others choose to patch the area or install a new pre-hung door to replace the jambs all together. Take some tips from DIYers who have been in your position, and see what solution will work best for you.

Original Post: Garage entrance door jamb rot repair.

SturdyNail Member


As you will see in the picture, the bottom of the hinge side jamb is rotted straight through.

Should I:

  • Patch it with Bondo Glass & Bondo?
  • Cutout, let's say, the bottom 1.5' of the jamb and try to match it with new wood?
  • Replace the hinge side jamb?
  • Replace both side and header jambs?
  • other suggestions?

Also, the threshold is pretty "spongy"--especially the portion that hangs out over the foundation. I'm considering attaching a piece of pressure treated or PVC under the part that hangs over the edge--fixing it to the foundation with a few Tapcon's and, maybe, some adhesive as well. Any suggestions?

That area does not get a lot of sun--as evidenced by the greenish tinge on the concrete--so I need to come up with a solution that will hold up well in that environment.

Thanks in advance for your ideas.

Highlights from the Thread

Norm201 Member

You can either repair it as you suggested or install a new pre-hung door. If you install a new door, that will give an opportunity to inspect and replace any other wood that may be rotting.

marksr Forum Topic Moderator

I'd either replace that piece of jamb or put in a dutchman (replace the rotted portion with new wood). For a filler to work you need to remove any/all rot! IMO it's easier/quicker to cut out the bad and insert new. Priming the bottom edge and backside of the new wood will help it resist absorbing moisture.

How far does the threshold overhang the block? At over an inch of overhang it needs support from below!

XSleeper Member

I agree the sill nose should be supported by a 1x4 or similar.

I find that a multimaster (oscillating tool) makes it pretty easy to cut and remove rotten sections of the jamb. I will usually pull out the weatherstripping and start my cut along that vertical edge. I remove the brick mould so that you can completely replace the wood behind it. A table saw is a big help. The new piece needs a kerf for the weatherstrip, and I use pvc for the repair, since it will never rot. I try to pump the end of the sill with construction adhesive since the ends where it was formerly attached to the jamb have since rotted off-- seems to help keep it from getting loose.