This turned out to be a fairly lengthy meeting, mostly because we were following up on the option to replace the SIPs in Tanglewood that our Builder consultant Dale had first mentioned a week or so back. I'd taken the assignment to track down some basic insulation and weight values for Architectural Engineer Scott, and then he was going to ponder what changes (if any) might be needed to the design.
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Turned out that this was all pretty positive. The LiteDeck we're using between floors allows us more flexibility for swapping out the SIPs with the ICF and Scott only had to make minor changes to the plans to allow this substitution to be made. It all worked out very well and ended up saving us around $5K in the construction budget at a greatly simplified design and a "tighter" seal overall--not bad a thing at all!
We then turned to discussion regarding the roof, and this is where I learned some interesting stuff. In the original plans I'd given Scott a long, long time ago (okay, it only seems like it) I'd assumed that the roofing would be SIP over most of the house since those were insulated and green and Earth-friendly, right? It was as close as I could get to matching the walls (ICF) while being as insulated as possible, yes? This was the Best Way to maximize my energy savings while shortening construction time, correct?
Er, not so much.
One thing that Builder Dale had mentioned to Architectural Engineer Scott and us via email was that he was pretty sure he could put in a better, more efficient roof over the library and great room using scissor trusses. The void would be filled with a couple of inches of expanding foam insulation (to seal up any air gaps) and then a blown-in insulation. Where the SIP roof would have an approximate value of R-20 (for the thicknesses we could find), the more conventional scissor truss roof would spec out somewhere between R-45 and R-47. Oh yeah, and the whole thing was estimated to cost around $21K less and could probably save a week or so in construction time.
My my. Tell me more!
We instructed Architectural Engineer Scott to go forth and see if this design was practical, as well as tasked Builder Dale to get bids and such so we could nail down the prices. If this looks promising we'll revise the plans accordingly and have to resubmit them with the initial changes, but when you're talking saving money and time while doubling efficiency I think it's probably worth the trouble.
Lesson Learned: Don't always assume the "greenest" technology is necessary the best or the most energy efficient. Sometimes there's a "tried and true" method that's faster, more efficient, and a heck of a lot cheaper.
Next up was a brief discussion of how we were going to handle the hardwood flooring in the apartment with the radiant heat we plan to install.. There's a certain style of hardwood (called Purpleheart) which we want to have in the apartment bedroom, but generally speaking hardwood and radiant heat don't mix well--the radiant heat ends up drying out and cracking the hardwood. You can see the general effect simply by cutting a section of a tree and leaving it out to dry for a couple of weeks; it will always crack usually from the heartwood out. (You don't have these problems with engineered flooring since they're a mix of materials that bring strength in multiple layers.)
We kicked around some possibilities and generally decided that our options are somewhat limited. We're going to try to build a shallow platform in that room and basically mount the hardwood onto this. With the radiant heat system down in the concrete itself, we'll attenuate the heat slightly and build in an "air void" between the hardwood and the radiant system itself which will serve to isolate the wood somewhat from the more direct heat. We hope this will help us avoid the worst of the problem....and if it doesn't, well, I guess that's what colored wood fill is for....
That was really the bulk of the discussion and we wound down quickly after that. Architect Scott asked how the building estimate was going and had touched base with Builder Dale a couple of times since their meeting a week or so back. We kicked around a couple of things regarding the work yet to be done (mostly clearing the downed wood) and I bragged on my Gator...it's really changed how we do work on the site.
So overall a great meeting. We're looking at an approximate $25K savings or so from where we were last week (we'll know more when we get an estimate), improved the overall design and we're very close to having our final drafts all done. Not bad at all.
We should be breaking ground soon. That's when the fun really starts!
Steven in Colorado Springs