Building a house from Structural Insulated Panels

I've in the process of building a house out of Structural Insulated Panels (SIP's). While it is questionable about OSB & Styrofoam being "Green", I elected to go this route because of how well insulated and air tight the house it. You can see videos and pictures on my blog at My10Acres.info. Some of the advantages are few thermal transfer points (studs only at panel joints), extremely low air infiltration (so low it is recommended your put in a heat exchange fresh are supply) and less lumber due to the inherent strength of a panel.

SIP's do make a nice tight house Jerry. It looks nice. If you had some PV panels do you think you can approach a net zero energy use?

That's going up quick! It looks really good too. How are you going to finish the exterior?

Hey Jerry, I hope all goes well with your choice. I am at a fork on the road in home design to whether go for more breathable or air restrictive home design. I always assumed that air tight homes were the ideal solution until I listened to a lecture by Bill Mollison making fodder of green homes here in America. He made some valid points that made me consider looking at a balance of more breathable homes with thermal mass features. I wish I had a link to give you but he spoke sarcastically when calling them "green" because they can accumulate undesirable toxins like radon or industrial byproducts from furniture or clothing. He also complained about humidity issues in many of these homes and how stuffy the air was so I would think thoroughly about ventilation. There were some other smug coments he made but I cannot fully do his arguments any justice because it has been a while since I have seen the lecture.

In your part of the world, SIPs are a great option. Over the life of the panels you will more than offset the energy inputs.

I am in rice country and am pursuing SIPs filled with rice hulls rather than foam for good R-value, lower cost, and the ability to do it myself. I will start with a shed and see how well they work. Heat is the issue here; but there are many other options to mitigate the sun rather than the snow and wind of MI.

Enjoy your new home! They are much more special when you have a hand in them, especially from design up. My brother and I built his over 25 years ago. I still have a strong connection to that place. It must be the blood and sweat one puts into it.

Glad to find some other SIP proponents here. Be meticulous with your panel joint sealing. Taping both sides seems to be a best practice and I like to caulk on top of foaming the joints.

As to the airtight vs. Breathable walls, Breathable walls do not give you enough control of ventilation. They tend to breathe too much or not enough. An airtight home with an erv or hrv gives you the most possible control of indoor air quality.

Dale, great looking house. Was there a reason for not hanging the floor systems? It seems like your 10 foot walls would definitely have allowed plenty high enough ceilings. For others interested, hanging the floor systems allows a tighter envelope, and easier, more efficient insulation details.

Matt Walker wrote:That's going up quick! It looks really good too. How are you going to finish the exterior?

Vinyl siding on the walls and asphalt shingles on the roof. We wanted to go with brick and metal roofing, but I couldn't get it to fit in the budget.

Brian Knight wrote:Dale, great looking house. Was there a reason for not hanging the floor systems? It seems like your 10 foot walls would definitely have allowed plenty high enough ceilings. For others interested, hanging the floor systems allows a tighter envelope, and easier, more efficient insulation details.

I assume you are talking to me as I don't see a Dale in this thread. We considered this but the builder/designer elected to go the route of building a floor deck on top on the walls. There were some issues with material usage that made this work better. Plus this does make it easier to run electrical into the walls. However we are having spray foam insulation applied to the inside all the rim joists after all the mechanical's are in which will give us close to the same thing, plus it fills any cavities around items coming through the rim joist (electrical supply, gas supply, furnace & water heater vent ...)

Regarding panel usage, you can save a lot of money if you design to the material. I don't know if this is the case with all SIP manufactures, but for Insulspan (the one we are using) the panels come in 8' x 24' or 8' x 20'. So in our case most of the first floor walls can be made out of a 8' x 20' panels (think cut in half to get 2 - 8' x 10' pieces) with very little waste. From the top of the basement wall to the roof is 14' (1 foot for the first floor deck, 10' for first floor walls, 1 floor for the second floor deck and 2' knee wall to give a little more head room on the second floor), which is more than half a panel. If we went with 8' ceilings in the first floor we could have used 1/2 of a 24' panel and hung the floors. But my wife wanted higher and Happy Wife = Happy Life so we couldn't hang the floor.

I hear you Jerry, sounds like you guys know what youre doing. Every SIP company does do things a little different so its great if you can select a SIP maker before or during design. Did you consider balloon framing; as in running the 8x24 panels vertically for both lower and upper level walls? I suppose Insulspan would need to run the electric chases the opposite way but I know its been done..

For others in the planning stages of any house with more than one level; spraying the floor band is the perfect match for spray foam but hanging the floors from fully insulated walls will create less air infiltration, thermal bridging and not require this step. A surprising amount of air can make its way through on the bottom and top edges of the floor framing members which can be reduced by sealing when framing everything up this way. Generally, with hanging floor systems all you need to seal is bottom of subfloor to top plate of lower wall and top of subfloor to bottom plate of upper wall.