With the dramatic decrease in the price of lumber, are SIPs monetarily dropping proportionately with traditional lumber? If so, what is the percentage decrease from 2007? 

timbeardmore,

You probably won't see decreases in price on SIPs due to lower timber prices. I am not an expert, but even with OSB SIPs, the vast majority of the expense is in the EPS or PU foam. If you are talking about steel sips, then timber prices might put downward pressure on the final cost, but wouldn't affect the material costs.

And, you will probably see that the prices of the foam are going up due to higher petroleum prices. That is not to say that the cost of fully finished (insulated) structures of timber won't go up due to higher insulation costs (if foam is used for the insulation).

Dick Mills

Our steel sip supplier has not passed on any increases in over a year and has not notified us of any pending increases

The price of wood products appears to be stable for now, although the lumber companies are nervous about what will happen if business picks up this spring. Unfortunately, SIPS and ICFs are dependant on foam which is petrolieum based, which means their production costs for raw materials are increasing as gas prices do. And don't forget about transportation costs.
By the way, our steel building suppliers are sending out price increases monthly, almost 10% in the last 2 months, with more guaranteed this summer. So count on the price of steel SIPS jumping, sooner or later.

Wes;

Our steel stud suppliers have also raised prices continuously over the last 6 months

BUT our steel SIP supplier has not, I believe they have pre-bought enough coil steel for the next year under old prices