I'm in the design stage of building a chalet style home in the northwest with typical trapezoidal windows for the great room. The designer is pushing the sips for the roof very aggressively with all its benefits. He says the company will send a rep out for a day or 2 to assist the contractor. The Contractor, who is very experienced with trusses and none with sips says a parrell truss system will work out fine for me, but he is afraid the sips will cause problems with not letting the moisture escape properly and that I would need forced air heating to reduce the moisture in the air as well as some other method to get rid of more of it. The designer insists I will have no issue with moisture at all if I go with sips for the roof. Who's right ?  Besides that, I definitely don't feel comfortable being the first sips roof install by my contractor

Siportruss,

We specialize in providing trusses and I joists for roofs with SIP walls for exactly the concern you have. The roof is a more expensive component to build with SIPs and much if not all of the benefits can ususally be achieved with trusses or rafters, spray foam for sealing, and blown in insulation for the extra R value. Find out what your price is with roof vs. without. And without you will be able to eliminate the rep on site. And while they may send him for free, someone had to pay for the plane ticket. Have your contractor review the connection details and especially the glue joints for doing the walls. It isn't rocket science. When you get your final numbers, make sure you weigh an inexperienced crew with the issues that you will find in the previous posts with roof panels. SIPs are definately superior but they are an upgrade and one you might not need if you expect any issues which would have to be disclosed to the buyer of your house, or when you get financing/establish resale value of your house. Afterall, unless you and your heirs plan to keep the house...

You wanted an unbiased opinion, and you got:



So, much for that. He is trying to sell you something. Do you trust his opinion?

The fact is, that for a true vaulted ceiling, SIPS are one of the best choices.

If you want to save money, use trusses. But don't expect the same thermal performance(with or without spray foam).

Without seeing your plans, an educated opinion can not be made.

Just beware of those whose statements are motivated by profit.

Moisture: Every new house should have a method for introducing fresh air. That said, you should have an ERV or HRV installed. They do make models that can be combined with dehumidifiers.

JC,

Why is it biased if he is not my customer? I am just agreeing with him for looking at the issue. And what makes your statements unbiased? Have you gone out of the business of selling SIPs so that you can provide impartiality? Perhaps you could offer some reasons why the thermal performance is justified.

The simple fact is that cost does play a part in performance as you tend to ignore. There are important considerations such as labor, need for energy and cost for energy that will figure into the equation. In my previous example, I separated my energy costs for heating/cooling from my total electrical usage and found that I have less then $240 in total costs per year. Even if I could get 50% better performance out of a roof upgrade, I would only gain $120/year and I would have to pay for the $$$ thousands in upgrades up front. That is reality for where I live. And any homeowner that wants to do the math should be applauded.

Now if I am building a simple roof design, my energy costs are through the roof, and a SIP plant is down the street, the math changes significantly. But please don't make the guy spend the money on an upgrade that MAY not be justified. I would rather tell him the issues, not get his business and save hime 10k then have him find out a year down the road that his 10k upgrade nets him $120/yr. and that he won't see a return for 84 years. But he sure will impress his neighbors with a blower test.

Let's see here. Maybe it's because I don't use this forum as a sales tool? And, maybe because I don't start my post out with a sales pitch?


He lives in Washington, where it just might get cold.


That's true, I don't ignore the fact. And, it usually boils down to less cost = less performance.


I'm not making him do anything. It's his project and his money.


As far as always taking the stance that SIP roofs are too expensive, one could also infer that maybe SIP walls are also too expensive. After all, we can build a wall with sticks for a lot less can't we? Better ROI! Everyone's happy! Aren't they?