Energy consultant's clear-eyed look at SIPs
Marc Rosenbaum is an accomplished environmental design consultant (Energysmiths, based in Meriden, NH). He likes SIPs. Upon his recommendation, several of his university clients have installed SIPs in large buildings. Marc will continue to specify SIPS where the product makes sense. Yet to date, all not has been peaches and cream with the SIP applications on his consulting jobs. The Good has been paired with The Bad and The Ugly.
Consider a building erected at a university in New England during the last several years. The crew assembling the panels had no experience with them. To compound that difficulty, the panels were being erected during a wet winter time frame, and the manufacturer didn't send a rep to the jobsite. Compound angles at complex valleys and rooflines were cut with a chain saw, leaving gaps that Rosenbaum says he could slip his arm through.right up to the elbow. "We pressurized the building and, using a theatrical fog machine, an experienced air sealing subcontractor was able to locate most of the holes and seal them. But the manufacturer supplied the crew with cases of those dinky little cans of foam you buy at the local lumber yard, instead of the 10-pound canisters that attach to a gun, so the sealing went very slowly and in many cases poorly. As a whole, the SIP process shouldn't have taken that level of effort, and it wouldn't have if the product has been installed correctly by an experienced crew from the get-go."
"On paper, some manufacturers appear to understand that they are selling a system that needs support, not just a product," said Rosenbaum. "Given the fairly low quality of workmanship on many commercial job sites, the SIP industry needs to provide bombproof details and more hand-holding. You need to spell out exactly what has to be done in the field to make the project a success, not a nightmare. In future commercial projects where SIPS are used, we'll insist on involvement of an experienced panel installer."
The biggest benefit Rosenbaum sees with SIPs is their installation as a cladding over the exterior of steel-framed buildings. "This provides a tremendous thermal break over the entire shell," said Rosenbaum. "On the project mentioned earlier we considered going with steel stud framing and sprayed cellulose. Looking back, I see that we were very unlikely to get the thermal quality possible with SIPs."
"In one college dormitory designed with a gazillion dormers, we recommended panels for the dormers. That way, all the dormers could be cut and assembled on the ground and then craned up onto the roof in a day or two. That's a really good solution compared to stick-framing them and trying to insulate all the off-size and odd-angled cavities, which is usually done terribly. They went with the SIPs roof system and it appears to have worked out well."
Rosenbaum summed it up this way: "I continue to see panels as one reasonable arrow in the quiver for people putting up large buildings of high thermal integrity."