I am new to the sips world and am toying with a design that I need some input on. Let's say we a have a 24' deep two story house, width 40'-48', with a goal of having a completely open first floor, three bedrooms up. Charlotte NC area. Deflection aside, spanning the 24' is not a problem, but would the sips walls be able to support all that weight? If not, does anyone have any suggestions?

Posted By lknbigfish on 25 Oct 2014 03:05 PM
I am new to the sips world and am toying with a design that I need some input on. Let's say we a have a 24' deep two story house, width 40'-48', with a goal of having a completely open first floor, three bedrooms up. Charlotte NC area. Deflection aside, spanning the 24' is not a problem, but would the sips walls be able to support all that weight? If not, does anyone have any suggestions?

In the end an engineer will have to review the calcs and stamp the design. Are you trying to use the SIPs as a 2nd floor?

Thanks, an architect will finalize the plans and an engineer will put his magic stamp on the design if it gets that far. I am in the early stages of this idea and wanted to check on the feasibility, I should have been more clear. I am looking at using sips for the walls, a slab foundation, probably lvl's for the joists, and trusses for the roof. I am just not sure if its even possible for the first floor sips to support upstairs with the lvl's spanning the 24' from the front to the rear of the house. It could be a stupid question to those who know sip's, I just have no idea.

Bigfish,

I was looking at SIPs for a similar type configuration and don't think you will have much problem with the SIP walls.

My design went to a PE and after some back and forth we got the stamp. I was originally wanting to use full length SIP wall panels (~18' - 24') using a internal ledger to carry the 2nd floor and to avoid a rim board that would negate some of the SIP insulation and air tightness benefits. The PE wasn't thrilled with that. He wanted to use the 1st floor SIP wall with double top plate to carry the joists and then 2nd floor SIP walls on that. This would require the rim board and yet another insulation/air detail that I did not want.

We finally decided of using longer 1st floor SIP walls to accommodate the joist depth, and a double plate and interior joist hangers to carry the load and avoid the need for a rim board. 2nd floor SIP walls as usual.

So SIPS carrying the load should be fine. Be prepared for a little give and take. There are a number of SIP details online that show these configurations that you can give to the PE if he/she is not familiar with SIP construction. I was also surprised with the amount of strapping/anchors the PE required for lateral/wind loads on a 2 story. In any case, it can be worked out I'm sure.

Posted By 3cityblue on 25 Oct 2014 05:30 PM
Bigfish,

I was looking at SIPs for a similar type configuration and don't think you will have much problem with the SIP walls.

My design went to a PE and after some back and forth we got the stamp. I was originally wanting to use full length SIP wall panels (~18' - 24') using a internal ledger to carry the 2nd floor and to avoid a rim board that would negate some of the SIP insulation and air tightness benefits. The PE wasn't thrilled with that. He wanted to use the 1st floor SIP wall with double top plate to carry the joists and then 2nd floor SIP walls on that. This would require the rim board and yet another insulation/air detail that I did not want.

We finally decided of using longer 1st floor SIP walls to accommodate the joist depth, and a double plate and interior joist hangers to carry the load and avoid the need for a rim board. 2nd floor SIP walls as usual.

So SIPS carrying the load should be fine. Be prepared for a little give and take. There are a number of SIP details online that show these configurations that you can give to the PE if he/she is not familiar with SIP construction. I was also surprised with the amount of strapping/anchors the PE required for lateral/wind loads on a 2 story. In any case, it can be worked out I'm sure.

Thanks, I really appreciate the info. How far did you span?

Our longest span was 16'. But span isn't the issue if I interpret your original question correctly. Span length will drive spacing/depth/type of floor joists. At 24' I would expect you will have a pretty deep and/or closely spaced joist design. The ability of the SIP exterior walls to carry that should not be the problem. You may end up with a more robust SIP joint connection (double 2x's vs. single) but I am pretty sure that the SIP walls will be structurally adequate (full disclosure, I am not an engineer).

floor joists hanging off 6" SIP wall javascript:amaf_insertHTML('');amaf_toggleInline(4927,3685,0);

Posted By 3cityblue on 26 Oct 2014 11:21 AM
Our longest span was 16'. But span isn't the issue if I interpret your original question correctly. Span length will drive spacing/depth/type of floor joists. At 24' I would expect you will have a pretty deep and/or closely spaced joist design. The ability of the SIP exterior walls to carry that should not be the problem. You may end up with a more robust SIP joint connection (double 2x's vs. single) but I am pretty sure that the SIP walls will be structurally adequate (full disclosure, I am not an engineer).

Yep, my main concern is the ability of the exterior sip walls being able to support the load. From the responses, it seems like that won't be an issue.