Cutting Roof Joists

[Sam the Cat]

So I have this curious problem. I need to move the scuttle hole that I use to access a section of my attic. The place I want to put it is in a closet that is 24" deep but there is a joist just about square in the middle of the closet ceiling. My roof is framed with joists 24" on center and at this point the span is about 20ft. I have always thought that the bottom horizontal member was pretty significant in maintaining the integrity of the rafter "system" and so I am dubious on whether this is a "doable" thing. In order to make this work, I would need to head off the member on both sides and remove about 24". I'll be chatting w/the county building guys next week, but thought I get a head start and see what folks thought.

[Colbyt]

In most cases the ceiling joist only supports the ceiling drywall and provides some cross-tie benefit to the roof. Cutting one and providing proper headers to maintain the structure should be no problem. A single header transferring the weight to the joist to the left and right would most likely be enough. If you want to err on the side of caution use a doubled header. As you said this is in a closet most likely the weight if it is carrying any will be supported by the side walls of the closet in any case. As always local codes supercede Usenet advice.

Colbyt

[Eric Tonks]

If it is a bottom chord on a lightweight manufactured truss using 2 x4s and

2 x3s, DO NOT CUT IT, it is under tension and cutting it will weaken your roof.

If it is heavy stick framing such as 2 x 6s you should be OK.

[ß©©ß]

There is a very good chance that if you cut that rafter, the entire roof will collapse either immediately, or the next time there is a heavy wind storm.

[SP]

Keep it up sam the cat!

"?©ß"

[Harry K]

One of the primary jobs of the joist is to tie the two ends of the rafter triangle together. Without it the load will try to spread the walls apart. Cutting one can be done but make sure that the tension that used to run across the member is somehow transfered across the opening.

Harry K

[bill a]

not a good idea. in rafter style roof, the ceiling joists are in tension, holding the walls together. if a joist is cut, blocking to the adjacent joists is not all that great, because the tension load needs to be met entirely by the fasteners. with some serious joist hanger bracketing, you might be have some success. btw, this is how older houses get that saggy, crooked look after later plumbing and heating modifications did this type of thing. bill

[Joe Fabeitz]

Bullshit! "?©ß"

[Colbyt]

Bullshit!

Why then are garages commonly built with only a "joist every other rafter. And that is modern code. I own garages that have a crosstied rafter every third or fourth rafter.

Colbyt

PS: I should have cautioned the OP to make sure he joist and rafter construction and not truss construction on my original reply.