I’ll keep this short and simple. Is there any reason to use housewrap on the outside of a timberframe with structural insulated panels, or is it redundant? I will be attaching wood siding to the house, which will be either cedar clapboards or vertical pine board-and-batten.
Thanks.
Key proposals for the next edition of the International Residential Code tackle room sizes, stair specs, emergency egress, and deck guards, among other requirements.
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Replies
Definetely.
Housewrap (at least the concept of a barrier behind the siding) has been around for a lot longer than Tyvek/Typar/etc. I'm assuming that you are asking because you think air infiltration is not an issue anymore. You still need a seconday barrier behind the siding. Siding is not weather tight, no matter how much care is taken during installation. The secondary barrier (preferably tar paper) will keep the majority of the rain off your sip's. Ideally you would apply vertical furring strips over the tar paper and nail the siding to that. This will give your siding a chance to dry more evenly and the rain a place to drain unhindered.
Jon Blakemore
Jon
At all costs in SIP construction you MUST protect the outside OSB of the SIP. Even with timberframe as the main support the outside OSB of the SIP panels IS PART OF THE PANEL STRUCTURE.
What I would do. . .
KM
I'm curious about how wide spread the practice of furring out the sheathing over the house wrap (either tarpaper or tyvek/typar) is. Would you say that this is one of the tements of "fine" home building?
Seems to me like most of the builders in my neck of the woods (SE MN) DON'T do the furring-out route...just side with whatever right over the house wrap.
Are there other areas of the country where furring behind siding is SOP?
I will be siding my new house this summer (Typar wrapped over OSB over standard stick-frame), so still have the option of furring out under either cedar clapboards or T-111.
What's the real value? Will it translate into higher re-sale?
The real value isn't something you'll get paid for at resale. It's greater longevity for both the siding and the paint job. It's a more durable house.
If anyone is interested in the science behind rain screen walls, either get Mark Snyder's article from FHB 137 or go to http://www.buildingscience.com. I go there regularly just to learn how houses really work. It's amazing how much of what I (and probably a few of you) learned coming up in the trades is wrong and sometimes, harmful.Arguing with a Breaktimer is like mud-wrestling a pig -- Sooner or later you find out the pig loves it.
What Andy says is very true. Siding will last much longer etc. Make sure you pre prime the siding both sides before installation.
BUT specific to SIPs
This system will isolate them from leaks in the siding to a great extent. Leaks always happen no matter how well it is done. We have all seen what happens to OSB when it gets wet.
The down side of a furred out system is the extra time for window and door openings. I feel this is time well spent but some will probably disagree.
KM
Is the benefit then lessened if one is siding with hardie? I have a timberframe, sip enclosed and typar wrapped house which will be sided in a few weeks.
Mike
My house is not SIPs, but I did use Hardi-Plank, and I did use a rainscreen. I really hate to paint. The rain screen might have cost me another $100 in material, and very little time. I just nailed up mason's lath, rough sawn 3/8 in. x 1 1/2 in. wood strips, over the studs as I went along.Arguing with a Breaktimer is like mud-wrestling a pig -- Sooner or later you find out the pig loves it.
So part of what you're saying is:
The benifit of the rain screen out-weighs the downside of additional penetrations through the house wrap.
?
I think so. Not that there were all that many additional penetrations. You really only need to tack the strip in place with one or two nails, then use siding nails long enough to penetrate to the studs.Arguing with a Breaktimer is like mud-wrestling a pig -- Sooner or later you find out the pig loves it.
"My house is not SIPs, but I did use Hardi-Plank, and I did use a rainscreen. I really hate to paint. The rain screen might have cost me another $100 in material, and very little time. I just nailed up mason's lath, rough sawn 3/8 in. x 1 1/2 in. wood strips, over the studs as I went along."
Do you mean that you nailed the lath over the sheathing and felt, to the studs?
Yes.Arguing with a Breaktimer is like mud-wrestling a pig -- Sooner or later you find out the pig loves it.
The number one reason I see for doing the furring on SIPs is that the 7/16" thick sheeting on SIP's does not provide sufficient grip for the heavy Fiber Cement siding. Without the furring strips, most SIP manufacturer's will recommend screwing the top and bottom of the laps so each lap of siding is tied to the one below it. That leaves a ton of exposed screw heads that are unsightly and prone to leakage.
IMHO, when using lap siding over SIPs, adding 3/4" furring strips at 12" O.C. vertical is the only way to do the job right. That is how mine will be done for sure.Kevin Halliburton
"I believe that architecture is a pragmatic art. To become art it must be built on a foundation of necessity." - I.M. Pei -