How SIPs Work
So now that we have discussed the major components that make up a SIP we would like to get into the specifics of how exactly SIPs work. There are two levels on which SIPs work. First they are structural and can replace the majority of the lumber required to frame a building in a conventional manner and second they create a super insulated wall system.
SIPs are similar to steel I-beams with the skins acting as the flange and the foam core the web. This configuration is incredibly strong and virtually eliminates the need for any additional lumber for structural support. In the instances where there is need for support for point loads an LSL or dimensional lumber is added into the wall system. With Earthcore SIPs any additionally required support is placed in the wall system at the factory, eliminating the need for job-site modification. Earthcore also gains additional strength from the type of foam that it uses. Instead of a
polystyrene foam, Earthcore uses polyurethane with has structural integrity on its own, plus, because polyurethane foams are an adhesive, and a secondary adhesive is not required to make our SIPs, the final unit is bonded together to form one cohesive unit. Eliminating the wood framing in a wall has several advantages. Obviously, using less wood is a better environmental choice, particularly, as mentioned in our article on OSB, the wood content in a SIP is from fast growth forests and 98% of the tree is used. SIP panels are formed in a controlled environment and made with engineered products so that walls are straighter and less susceptible to warping and bowing. The largest advantage, though, is that with less wood there is more room for insulation.
As you can see in the example to the left, eliminating the wood within the wall allows for continuous insulation from top to bottom and side to side. This increases the performance of the wall by eliminating the thermal breaks caused by the wood members of a conventionally framed wall. In other words, in a conventional framed wall, at every 16″ on center, the insulation of that wall is broken. This not only allows areas for the air outside of the house to penetrate into the “conditioned” space of the house, but decreases the R-Value of the wall at every point where there is wood. Wood has an R-value of .5 for every inch so in a wood framed house you decrease the R-value at these points from R-19 in a 2 x6 framed wall to R-2.8. In comparison, in an equivalently thick Earthcore SIP structure you have a continuous R-42.
There is also the issue of air infiltration to which we eluted to previously. The wood studs in a conventionally framed house break the continuity of the insulation which could lead to gaps in the insulation as well as points where air can penetrate in the conditioned living space. With Earthcore’s foam core there are no points of air penetration and with the foam spline and the application of foam at all connection points a SIPs house can be the “tightest” house available of all the building methods in practice today. This is accomplished, too, because SIPs can panelize larger portions of the building creating a wall system as opposed to components being cobbled together in sections. As an example, Sustainably Built, a Boulder, CO energy modeling company, recently tested a home built with SIPs that measured 1 natural air change per every 23-24 hours. Todays energy codes only require one natural air change every 3.5 hours. This increased “tightness” helps reduce wasted energy to heat and cool a structure and also allows for greater control of the indoor air quality which produces a healthier environment in which to live and work.
Category: SIPs Components, Uncategorized | Tags: air infiltration, enviroment, green building, panelized walls, Polyurethane Foam, SIPs, structural insulated panels, thermal performance, tight houses 9 comments »
March 10th, 2010 at 4:51 pm
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March 29th, 2010 at 9:05 am
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And want to ask you: is this blog your hobby?
March 29th, 2010 at 12:02 pm
Thank you for your comments. This our business website and we do manufacture the products that we write about.
April 8th, 2010 at 12:50 am
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And according to this article, I totally agree with your opinion, but only this time!
May 28th, 2010 at 7:03 pm
My name is Piter Jankovich. Only want to tell, that your blog is really cool
And want to ask you: is this blog your hobby?
June 1st, 2010 at 7:03 am
This blog is an extension of Earthcore SIPs which is a manufacture of structural insulated panels. We simply want to provide this fantastic product to as many builders out there as possible.
July 7th, 2010 at 11:59 pm
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July 19th, 2010 at 9:02 am
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