Hello,
I am a practicing timber framer/designer and am currently working on my own house.
I have before me two bids on SIP panels. One for a urethane panel with all the bells and whistles and the other is a EPS panel with all the bell and whistles. Bells and whistles include top companies in the area, precut, conduit or chases, etc.
The bids are within $500 of each other.
Looking for your pros and cons to help in my decision making process.
Thanks for your time.
Brice

I've decided to go with the urethane panels for my house/office project for a couple of reasons.

The greater R value/inch allows me to run a standard 2x4 wall thickness so no additional charges for jamb extensions on the windows.

Also I've never had an adverse reaction to urethane compounds while I have had mild respiratory reactions to polystyrene.

Notwithstanding any preference for your plastic of choice I would pick those panels with built in chases for wiring. Saves untold messy hours.

I'm really surprised that Urethane and EPS were that close. Back when I was researching this, the Urethane panels were *significantly* more expensive. Maybe Urethane came down or EPS went up.

Some additional things to consider.

1. Firmness of contract price. Is the price locked? EPS and OSB are both commodities the fluctuate wildly.
2. Shipping charges. Do you pay? Do they pay?
3. Drafting fees/charges. Is that included or part of the estimate.
4. Installation. Is that an option? If so, how much? Fixed price?
5. If you need to make modifications to the urethane panels, how easy is that to do? (cutting, reshaping, etc.)
6. Other characteristics of the two material you might want to consider side-by-side are R-Value (yes, Urethane is much better), structural strenght, off-gassing, longterm durability, fire-resistance and insect resistance.

Good luck with your project.

-Steve