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Skylight shaft - offset rafters/ceiling joists

Skylight shaft - offset rafters/ceiling joists

Old 03-23-21, 05:30 PM
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Skylight shaft - offset rafters/ceiling joists

So I installed 2 Velux skylights that fit between my rafters (16” centres). Did not realize until cutting the holes in the ceiling that the ceiling joists were off centre from the rafters, thus making the joists on one side block the skylight opening... see photo. What is my best option for a fix? To me, running a 2nd ceiling joist seems to be the only option but I really want to avoid structural work since I plan on getting a beam installed into my house soon and that will need an inspection. Any suggestions?
Old 03-23-21, 06:36 PM
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There is no solution that doesn't involve structural work. So just get a permit and have it inspected. Moving ceiling joists is typically not a big deal. But we would need more photos from above to know for sure.

Knowing the size and span of your ceiling joists would really help. And I assume you only need to move one joist, not both of them. Without knowing any of that...

The joist on the left will likely need to be doubled (probably on the opposite side that the rafter is not on). The doubled part of that joist must sit on load bearing walls. (I assume the joist on the right is the one you want to cut.) And the joist to the right of the one you need to cut would also need to be doubled just like the one on the left.

Then you cut out the joist that is in the way... (cutting out 3" more than you want your rough opening to be) and then head the cut joist off on each end, meaning you put a joist perpendicular... in between the ones that are doubled, to cap the cut ends of the section of joist you removed. Use joist hangers everywhere with the proper nails and you won't have anything to worry about.

Once you have done that part, then you can frame the width in exactly the way you want.

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