Would you like to do a 10 year followup on my VT home built with advice from this forum??
10+ years ago Martin Holladay answered several questions by me in this forum and in 2011 Scott Gibson wrote an article (with a rendering of my home which Imust have posted somewhere), unbeknownst to me, about “How to Protect Structural Insulated Panels From Decay” in which I was mentioned.
It’s been just about 10 years now since I built my home. We used Rooftopguard taped at the seams over the top of the T&G ceiling boards and underneath the 14 inch thick custom SIPs. All of this was installed by Jim Giroux’s crew from Vermont Frames. Over the top of the SIPs we used the GAF DeckArmor and then used furring strips to do a stood off vented roof above the SIPs. The vented roof upper layer is plywood sheathing covered with asphalt roofing paper and then a standing seam metal roof. Even with the shallow 20 roof pitch we tend to have very little standing snow on the roof and virtually no heat loss through it.
So far this roofing system seems to be holding up well.
Also, to improve efficiency, we did not let the rafter tails from the timber frame extend outside the outer walls. They are enclosed within the 6 inch SIP outer walls. This allowed the RoofTopGuard to get lapped down from the roof and over the ver top of the SIP walls. The SIP walls themselves were painted over with StoGuard liquid applied water resistant membrane which was painted up onto the RoffTopGuard to, in effect, create a single water resistant barrier over the entire house. We used wavy edge hemlock siding from Heath Lumber in North Hyde Park as our siding and also used strips to stand it off and leave a vented channel above the StoGuard treated walls.
So far the one big problem we encounter is that wasps seem to love the vented space behind the siding on the south and west walls and they are pernicious despite a regular pest control regime.
I designed the house myself with help from your forum, Vermont Frames, a contractor from Montpelier and one or two others. I ran my design through the REMDesign SW package and I am happy to say that the house has, in actual practice over 10 years, performed exactly as REMDesign predicted.
Our home is Efficiency Vermont certified. Even though I live in Northern VT (7700 degree days) I use only 250 gallons of propane (avg 93,500 BTU per gallon) since my mother in law started renting our basement apartment and was using 1/2 that when the basement was unoccupied for ALL our heat, hot water and cooking. I do have two 10 tube banks of Solar thermal DHW heating with an 80 gallon superstore drainback reservoir that in the summer gets up to 140F and a drain water heat recovery system to help with DHW. I also have a small 30,000BTU wood burning Nectre stove (aka the Vermont Bun Baker) which we heat with and cook on in the winter using wood we harvest ourselves from our lot. Typically we use about 1.5 cords a year. On any sunny day in the winter, even down in the single digits, we don’t run the wood stove or the heat as the house is designed as a passive solar house according to principles found in The Solar House by Dan Chiras.
If you’d like to call and/or visit (I live in Hyde Park, VT and I think Martin lives less than an hour from me) to do a real world 10 years out follow up on a home built with a lot of advice from your forums I’d be happy to work with you.
Sincerely,
Jay Hersh
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Replies
Jay,
Thanks for the update. It's good to hear that a properly sealed and vented SIPs roof - and indeed the whole house - performs well. Too bad about the wasps. How were the openings in the rain-screen cavities covered?
The wasps actually go up into the air space in between the siding boards because we used a special vented bug barrier (sorry forget the name of it) at the top and bottom. They have nothing but time on their hands and so they found other ways in. We've had the exterminator fog the space but they keep coming back because it's the south and west walls are just too tempting a location for them
Jay,
It's always something. I have a friend who builds on the Canadian prairies. The first house he did with a rain-screen the cavity almost completely filled with ladybugs, which are also impossible to keep out.
Again, good to hear you had a successful build.