Looking for a SIP installer for my project in Redmond, Washington state. Know anyone? Anyone to recommend? Can send engineered SIP shop drawings for bids.

Are you doing wood or steel SIPs?

If you are doing wood SIPs for the roof, best read this article and vent that roof. Especially in a humid and wet climate like Redmond:

BuildingScience OSB Roof SIP

Surprisingly enough, I don't think the Puget Sound region qualifies as a "humid" climate. We get a fair amount of precipitation, but we also dry out pretty well in between. Not sure how that affects the recommendation to vent a SIP roof like that.....isn't venting just about always a good idea?

Posted By ICFHybrid on 07 May 2012 11:12 AM
Not sure how that affects the recommendation to vent a SIP roof like that.....isn't venting just about always a good idea?

You would think it would be but it is not standard practice to vent a SIP roof. If you ask a wood SIP manufacturer if you need to vent above the SIP roof they will emphatically state "NO!"

The main reason is that not having to vent is one of the "selling points" of wood SIP roofs. If you have to vent above the roof, then you are creating more work, costs, etc. You have to add another layer of OSB onto the roof after you fur the OSB SIPS, that adds substantial costs $$$.

Places that have very cold and humid winters will experience the problems at a quicker level. In my opinion, I believe we will see this above roof venting become mandatory in the next 3-5 years due to all the complaints and problems that are surfacing. It will become standard practice when enough people voice their concerns and enough lawsuits hit the courts.

Does anyone know if 2012 IRC addresses this?

Yes, this is wood/OSB SIPs.
A few local SIP experts don't think it's necessary to put a "cold" roof above, but I guess it's a good precaution.
So, are there any SIP installers that want to install some SIPs in Puget Sound area? :)

Posted By Leon Hui on 08 May 2012 04:21 AM
Yes, this is wood/OSB SIPs.
A few local SIP experts don't think it's necessary to put a "cold" roof above, but I guess it's a good precaution.
So, are there any SIP installers that want to install some SIPs in Puget Sound area? :)

I would read that BuildingScience article I referenced in the above post and then it will be up to you whether or not you want to vent the SIP. Venting is just the nature of the beast when it comes to wood. Especially on a roof.

If you chose to do a cold roof, let us know what the cost difference is between doing one and not doing one. Not knowing the roof size, I would guess that it will cost you around another $3k - $6k to do a cold roof above the SIPs.

Leon, I live in the area myself and I bought my osb panels from Premier panel in Tacoma.I did it myself and don't know a builder but I'll bet that premier can help you with that. I did do a vented roof and Premier did not advise me against it. Their attitude was pretty much that any type of additional protection just makes sense. I also put a 1/4" air space between my panel wall and hardi siding.

So you have a vaulted sealed SIP roof, but you also did a cold roof, i.e. you added furred out sheathing on top of the SIPs? What did you use for roofing? Do you have a low pitched roof? I have an inverted butterfly roof, not sure how I would even vent that?? Anyone have ideas?

Posted By vb on 08 May 2012 10:45 PM
Leon, I live in the area myself and I bought my osb panels from Premier panel in Tacoma.I did it myself and don't know a builder but I'll bet that premier can help you with that. I did do a vented roof and Premier did not advise me against it. Their attitude was pretty much that any type of additional protection just makes sense. I also put a 1/4" air space between my panel wall and hardi siding.

Yes I have a vaulted roof with an airspace similar to the detail shown by lbear. I used composition roofing. My roof pitch is 6/12 with only one valley it is pretty simple.

How to vent a butterfly roof? Now that I would like to hear. I know that they can be done and maintained correctly but you do realize that butterfly roofs are a recipe for troublesome roof leaks?

but you do realize that butterfly roofs are a recipe for troublesome roof leaks?

Not if you do them right, employing sound principles of building science and modern materials and techniques.

At the risk of a lot of flack, the roof problems first reared it’s ugly head in Alaska. The problem was closely investigated, and it was determined that there were air leaks at the roof seams. Warm moist air would leak up through these cracks, hit the cold air and form condensation at the seams, deteriating the OSB. Upon inspection, obvious, major deficiencies were found, such as missing spline connections, missing pieces of lumber, missing foam and missing adhesives. This wasn’t an inherent problem with the SIP panels, but a direct result of poor assembly methods and shoddy workmanship. I've seen many rotten roofs around poorly sealed plumbing penetrations and skylights.

As anyone who has built a SIP home knows, it specifically states in the assembly instructions to apply a special sealing caulk to all surfaces of the panel splines and the manufactures supply a sealing tape to apply to the inside of the roof panel seams. Like any other roof, all roof penetrations and valleys must be very carefully sealed up, inside and outside and as a part of normal roof maintenance, should be checked at least once a year. A couple of tubes of Black Jack is a whole lot cheaper than a new roof.

Carefully follow the factory assembly instructions, use recommended roofing practices and check your roof, siding, windows, weather stripping and anything else that protects the outside of your house once a year as a matter of yearly preventative maintenance.

I'm not recommending against a cold roof or venting over the SIP roof. I'm just making the point that the roof assembly must be assembled correctly to achieve the best results.

Steve
GrandCountySIPS.com