I’d like to frame up a 4’X8’ hole in the ceiling of my garage. Rafters above are 2x6 on 24” centers. So I’d have to cut through 4 of them to do it. Obviously I would have to make a really sturdy frame. Is this even possible or reasonable?

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    it is possible. that sort of thing is done in floors to make stairwells. – jsotola Jan 12 '18 at 2:26
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    I get the feeling you should contact a structural engineer. This kind of work probably requires permitting, which in turn requires drawings and load analysis. Check with your jurisdiction, but I'd advise against doing it completely yourself. – Hari Ganti Jan 12 '18 at 2:44
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    do you really need a full 8 feet? You get like 7ft-10+ with only three cut..and of course if you turn it the other way maybe only cut one. – agentp Jan 12 '18 at 13:43
  • Rafters or engineered trusses? The latter would require doubled (or tripled) girder (beam) trusses at each side and beams between to carry the truncated trusses. It's not a simple thing. – isherwood Jan 12 '18 at 14:43

If you have a hand framed roof with a non-structural ridge beam and you want to cut the rafter ties, then you will need to add collar ties. The rafter/collar ties are in tension, so you need one or the other to prevent the roof from collapsing in on itself and pushing the exterior walls out. The other option is to add a structural ridge beam for at least that 8' section, but that's not an ideal solution.

If you have a hand framed roof with a structural ridge beam, then there is a chance you don't need rafter/collar ties at all. It depends on what it looks like up there.

If you have engineered roof trusses with metal gussets, then it gets a little more tricky. An engineer would definitely need to get involved.

If you upload some pictures we might be able to help you size it, but more than likely you'll need to contact a contractor or engineer in your area.

Roof Diagram

  • All thanks for your help. I’m thinking I used the wrong word and caused major confusion with “rafters”. I’m talking about ceiling joists above my garage. I’ll see if I can upload pics. – user80257 Jan 13 '18 at 4:38

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