I am wood framing concrete garage door opening described with pictures in this question.

Top concrete header is about 2" inches out of level across 9' opening length. I want to install 2x8 PT header under it and make it level. So I will have 2" gap on one side. What is the best way to do it? I am thinking of just cutting short piece of this 2x8 and using it as a shim in the right place in the gap. Will it work? Does it make any sense to fill the rest of the void with something like cement patch?

2 Answers 2


The new lumber door header will not be structural. Go ahead and frame the door rough opening plumb and level with your lumber and spacers. Use shims to snug it up to the concrete. Get creative with your trim to conceal the imperfections.

  • I should have mentioned, be sure to secure the new rough opening door frame to the existing concrete opening. This may involve using some Tapcons or Ramset nails to firmly secure the jacks and studs to the wall. Even if it requires securing some spacer blocks etc., the frame wants to be rigid all around. Commented Mar 27, 2012 at 11:41

Is the header structural? If so, then you'd likely want go scribe your header's top to match the uneven concrete and then cut it to match.

If it's not structural, then just set it level, and take care of the gap with your casement/trim.

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