When planning my addition, I intended to stud within the frame and use fiberglass bat insulation so I had my foundation poured to be flush with the outer face of my sills. I am now contemplating whether or not I could change my mind and use SIP's.

The frame is started so I can't modify it.

Has anyone used SIP's to enclose a frame without having a foundation overhang to sit them on? What was your method?

I don't see why I can't simply let the sip's "hang" from the mounting screws I apply them with and allow the 5-1/2" overhang around the house at the foundation line.

Shaun,

All i did on my frame is just offset the sill plate one inch over the edge of the foundation wall. Without the shelf there to set your panels on it makes it alot harder to hang them.Trying to hold them and nail them in place. Granted i just did a conventional pressure treated sill with 2 by 10 joist. Some folks might cringe at the words pressure treated but i guess i'm not a purest to the core. I didn't want to make it harder on the concrete guys to form up the walls to odd measurements or have to shrink the size of the frame itself to accomidate for the 1" shelf.

Also you can use layers of pink board(or blue) to match up the overhang of the panel. On the last 2' of insulation on your foundation wall put two layers of 2" and one layer of 1 1/2" to get your 5 1/2". (i think thats what you said,5 1/2"). It's alot easier when you put your insulation on horizonally. then you can do a stucco on the outside of your rigid. It works well, then you don't have the little jog at the bottom of your panel to the wall. Anyway i'm gettin' a little of the subject, hope some of this helps.
good luck....ZAC

Shaun:
Whatever you do, or however you do it don't forget to use a piece of flashing between the bottom of the sip panel and the support (if any). To prevent the chance of bugs, especially ants, from boring a hole into the underside of your panels, and making a home in there.
The flashing should be in the shape of a "Z", to go up behind the panel, under the panel and down the outside of the support, (if used).
This was told to us at the recent eastern conference.
Good luck with your project.
Jim Rogers

Hi Shaun,

My first recommendation would be to contact your SIP supplier, as I suspect such an installation would void the panel warranty.

I'm assuming by SIPs you mean panels with OSB faces both sides. I wouldn't even think of hanging curtain-wall panels [sheetrock inner face] that way; the sheetrock is in no way structural, and couldn't be counted on to bear any weight. Even in panels with two OSB faces, the unsupported weight, primarily of the outer skin, will not be adequately taken care of by the nails or screws, which will tend to bend, deflect, or shear. Any movement could cause delamination and failure within the panel.

I think the only way to support the panel edges in your case would be to frame the deck with an overhang. Your local Building Inspector would probably require an engineer's stamp on such a modification, and it's likely to lead to complex [read expensive] framing changes.

Good luck, Leon

Hi Shaun - you didn't say whether your frame is on the foundation or just being cut. If the foundation is still fully exposed, you could bolt angle iron (of appropriate size to carry the SIPs) to the foundation. Depending on what type of foundation you have, you may be still be able to do this even with the frame in place. With a poured concrete foundation, this is a simple matter. Another, albeit somewhat more complex, solution is to form a concrete ledger attached to your existing foundation to create the required profile to support the SIPs. This requires a secure union between the ledger and the present foundation. There are several ways to accomplish this. A local concrete contractor could give you the best solution for your locale. Good luck with your project. JEK

Thanks for the replies, guys.

My sills are already in place on my poured 10" foundation walls, set flush to the outer face of the foundation.

I have considered building my deck with a 3" overhang all the way around. My building inspector is pretty accomodating and shouldn't have a problem with this, the frame posts would still sit in its originally designed location. My main deck will be dimensional 2x8, 12" c-c. I will just have to insulate the inside face of the 2x8 plates around the deck as the SIP's will not cover them in this approach. I'm building my 2x8 deck completely on top of the decks timber structure vs, using joist hangers. anyway so this would not be a major design change.

The angle iron idea is an interesting one as well and certainly possible.

I have also considered attaching a presure treated 2x4 ledger strip to the outer face of my sill beams all the way around, 3-1/2" face to the sill.

I'm only just beginning to consider "SIP" construction so am using it as a generic term. I was not aware that their are differences regarding the inclusion of drywall vs. OSB facing.

I will of course research the details of these products more before i decide what to do.

thanks again.

Shaun

Shaun

I don't know what size your posts are, but is it possible you could hold your posts in to allow the SIPs to land on the foundation?
The area of post landing on the wall may be enough to carry the load and if not, (check w/an engineer) perhaps with the help of the afore mentioned angle iron either at the top of wall or lower with the post notched to reach it. If this necessitates you could add sill to the inside of the wall by drilling anchors where needed (not as time consuming as it sounds). Nothing like changing the plan eh?

Oops...

just read the part about the frame being started....nevermind

Oops...

just read the part about the frame being started....nevermind