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-   -   Move joists for higher ceiling (http://www.diychatroom.com/f19/move-joists-higher-ceiling-158621/)

jgrohol 10-01-2012 06:08 PM

Move joists for higher ceiling
 
4 Attachment(s)
I just gutted out an addition to our house. I am planning on updating the insulation, electrical, and flooring. During this I am checking the framing and structure to make sure it's all good and see what needs to be replaced. One of the items I came across was the ceiling joists. While I have the room gutted, I thought it may be a good time to raise the ceiling. It wouldn't be a straight-up vaulted ceiling, but I think I can raise it 2-3 feet. There would still be a flat part where I can install can lights and/or ceiling fan and yet still have the angled sides (roof) leading up to the flat part. The room has many windows and I think this would help open it up more.

I have a few pictures attached of the joists and rafters. The joists are straight across from top-of-wall to top-of-wall. About 15-16' in length. All joists and rafters are 2x6's.

My questions would be:
Would it be as simple as attaching new joists to the rafters a few feet above where they are now? Then remove the existing joists?
Is there a special way to anchor them to the rafters? (Guess I need to check local codes as well)
If I raise the ceiling, some of the roof rafters will be 'exposed' on an angle to the room. Is there anything special needed to insulate that? Vapor barrier?

woodworkbykirk 10-01-2012 06:23 PM

ive done it.. you have to check if its ok with your local inspectors first..

for going about it.. rent a 360 degree rotary laseer level to strik lines on every rafter.. this will give you a line to fasten the new joists to.. we do it with construction adhesive and air spikes typically

sixeightten 10-01-2012 06:25 PM

Those ceiling joists are an integral part of the structure. Probably gonna need to beef up the roof in order to pull off what you propose. A structural engineer will be needed to size everything correctly.

Daniel Holzman 10-01-2012 06:45 PM

Sixeighteen is spot on. The ceiling joists hold your walls together by resisting thrust generated by the rafters. When you raise up the ceiling joists, you are creating a structure which acts something like a truss with extended legs. The further up the rafters you go, the more thrust the hybrid roof structure is going to create on the walls. The analysis is not as simple as it seems, and you really should get a structural engineer to examine the loads and determine if you are going to create bending issues in the rafters, thrust issues on the walls, or twisting loads on the framing.

woodworkbykirk 10-01-2012 07:37 PM

i did this about 7 weeks ago on a large reno i did. i have pics on my phone however do to memory card issues in it i cant get them off the phone.

we stick framed the roof as per engineers spec. normal situations would call for trusses but the the roof was too comlicated with tying in for trussses to work. if i can get the pics ill post em

jgrohol 10-01-2012 07:41 PM

Yeah if you can please do so. I'd like to see what you did. If I don't raise the ceiling I will need to replace some joists as they are warped. I'm assuming I can knock out one at a time and put a new one in?

sixeightten 10-01-2012 07:47 PM

Quote:

Originally Posted by jgrohol (Post 1021549)
Yeah if you can please do so. I'd like to see what you did. If I don't raise the ceiling I will need to replace some joists as they are warped. I'm assuming I can knock out one at a time and put a new one in?

Correct.

jgrohol 10-01-2012 09:23 PM

I was speaking to my uncle-in-law who is an architect. He was stating that even I am able to do it, I would only be able to go 2' possibly 3' higher. I think the work to go into getting someone to check it out, do the work, and only get that much out of the ceiling may not be worth it. I am getting the details and measurements so he can do the load calculations and go from there.

Thanks for everyone's input.

woodworkbykirk 10-02-2012 04:40 PM

in the situatation of the most recent one.. we had to frame our walls at 7'2" to tie into the existing but the ceiling was really low so we simply increased the height of our ceiling joists by 12".. they were nailed to a laser line as mentioned earlier.. but at the peak our rafters were notched to actually bear on a 2 ply lvl ridge beam.. with 3/4" plywood gussets cut to lock the rafters together at the peak.. both glued and ring nailed on both sides of each one

GBrackins 10-03-2012 09:45 AM

Quote:

Originally Posted by Daniel Holzman (Post 1021502)
Sixeighteen is spot on. The ceiling joists hold your walls together by resisting thrust generated by the rafters. When you raise up the ceiling joists, you are creating a structure which acts something like a truss with extended legs. The further up the rafters you go, the more thrust the hybrid roof structure is going to create on the walls. The analysis is not as simple as it seems, and you really should get a structural engineer to examine the loads and determine if you are going to create bending issues in the rafters, thrust issues on the walls, or twisting loads on the framing.

I would suggest you pay close attention to what Daniel is tell you here. if done incorrectly you will cause the tops of your walls to push out, and potentially cause damage to your rafters. He knows of which he speaks.

Good luck! :thumbsup:

tony.g 10-03-2012 04:14 PM

1 Attachment(s)
Quote:

Originally Posted by GBrackins (Post 1022813)
I would suggest you pay close attention to what Daniel is tell you here. if done incorrectly you will cause the tops of your walls to push out, and potentially cause damage to your rafters. He knows of which he speaks.

Good luck! :thumbsup:

.....

GBrackins 10-03-2012 04:24 PM

tony!!!!!

when did you stop by my neighbor's to make your sketch????????


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