My wife and I live in Lawrence Kansas in an 1885 victorian. We have plans to build an addition to the back of the house, breaking ground in August. However, we originally didn't plan on SIPS, and our plans are probably not ideally suited to them. Also, I'm 100% positive that the walls aren't perfectly plumb or square. My questions are: Are SIPS better suited for new construction than an addition, and if not, will there be problems trying to line up straight and plumb SIPS to a not-so-straight original house? Also, we're going to be the GCs, and are somewhat wary about finding a framing crew with a lot of SIPS experience. ACHFoam in KC is probably the closest SIP distributor (R-Control). Anyone know of any more or some good crews nearby? Details: It's a two story addition, 10 foot ceilings, ful bsmt. since we have to 4 ft. for frost anyway, about 1400 sq. ft. I think but will doublecheck. Glad to be on the forum and thanks for listening.

How about the guy who wrote the book? Think he could be closer? Michael Morley - President 700 Mississippi Street Lawrence, KS 66044 Office: 785-843-7007 Fax: same Email: [email protected] Web site: www.sipsmart.com

SIPs are well suited for most construction whether new or remodel from a construction standpoint. From a cost standpoint, you have to look at things like engineering, shipping and labor. Your shipping shouldn't be too bad as you have a big enough addition to fill a truck.

I haven't used SIPs in remodel and no one provided any feedback the last time I suggested that a lower return is theoretically possible. Your HVAC is like sucking a coke through a straw. When there is a hole, you lose efficiency. I am not sure how great a performance you will get when building an addition with little or no holes that is attached to the leaky house. If I put multiple holes in the straw, it doesn't seem much worse then the first penetration. So with that said I would question the bottom line efficiency. It would be interesting to have someone report some actual numbers per foot before and after a SIPs addition. Perhaps you will be the one.

There are a couple issues to watch out for. First, you may have to deal with issues in wall thickness. I just did a home with a SIP dormer above an interior wall. The extra OSB created some issues as the framing crew isn't used to dealing with an occassional extra 7/16" skin. Luckily an extra sheet of drywall is an easy fix. But that probably won't work in a remodel as your old house is where the extra thickness would be needed. Obviously if you are not continuing an interior wall with the addition it wouldn't be an issue.

Thanks both for your replies. I would contact Morely, but--and this is obviously heresay--two subs/friends involved in our project have not had positive experiences, which is why I get a little nervous about SIPS. If everyone were building with them around here, it wouldn't be an issue. On the HVAC note, you're right, efficiency is my biggest concern. The original structure is better than a 1984 addition at retaining heat/ac, but we're still pretty leaky. At the same time as the addition, we're planning to gut most of the interior of the original house and I'll be addressing what insulation problems I can. However, most of the old sash windows will stay. I'mplanning to put some thin insualting board in the sashes on the exterior side, and spray foam where it won't interrupt the sash operation, but that's about as efficient as we'll get. Also, there will be no interior walls that extend into the new space. My main question still is: Would you build with sticks a couple of feet into the new addition adjusting any angles to make level and plumb, and then start in with SIPS? It seems like that may be missing the point of SIPS while also increasing waste by not using standard sheet size. Also, the new addition will tie into the original house roof (also probably having sag/pitch issues) so I'm wondering about SIP roof or trusses over SIP walls. Our addition, while it would be great to have SIPS may not be the ideal project for this application. Just looking for an honest recco. Could we still see savings over the long haul? Thanks all, Jeff