Thinking about who the reader of this newsletter is most likely to be, tells me that an article citing the familiar and conventional list of SIP construction advantages over stick construction would have you turning this page right about now……but not so fast! There are additional applications where SIPs might successfully replace conventional interior framing as well as be the material of choice for external "envelope" framing.
We were involved some time back with a proposal for in-fill housing in some pretty rough neighborhoods in a major east-coast city. It seems that the policy of the local community development not-for-profit organization was to bulldoze any abandoned dilapidated housing before it would become a crack house or continue to blight and depress the remainder of the housing on the street. There was great psychological advantage to having a blank lot rather than a dangerous ruin on the block. But soon enough, the empty lot might turn into a dumping ground or hangout for trouble waiting to happen. The best plan was to quickly get a new house up and operating on the site right away.
The idea was to focus on speed. A design was arrived at that had kitchen, bathroom and stairwells worked into one module about 8-feet wide that would be factory plumbed, wired, furnished and finished that could be trucked to the site and craned into place. The rest of the building - two or three stories - was shipped as SIPs usually are, except with windows installed. There were so few remaining walls that it was decided to make them of SIPs for two reasons; it was thought that "changing horses in mid-stream" - using either metal or wood sticks, would only be less efficient in terms of organization, and that again, the SIPs would all be factory pre-cut and go up faster. We all have had experience with SIP envelopes going up in as little as two days, what was hoped for here - and priced into the proposal - was that the whole building would be up, closed in and locked up in less than a week.
Conventional construction with its associated conventional timetable allowed more a huge amount of "shrinkage." An open construction site was like a neon sign saying, "Come and get me!, Help yourself to plenty of Good Stuff!" This would significantly contribute to jacking up the cost of the project and make working on the project a nightmare. For example, just when the project was rough-plumbed and the walls scheduled for rocking, the contractor would show up the next morning only to discover that much of the piping had been ripped out so sheetrocking couldn't take place. You can see how the cost and schedule would quickly spiral out of control. Being able to lock up very quickly didn't just have enormous value - it was everything! Unfortunately, this project did not get past design-development and pricing stage, but it was made clear by the development corporation that they didn't care about energy efficiency, or "green" anything, but just the security advantage, only possible with SIPs utilized for all the components. This project would have been a great success.
Another project that is still in the design stage at the time of this writing plans to utilize SIPs for the front and rear walls of this multi-story row housing and pre-cast, pre-stressed concrete for floor slabs bearing on steel framed party walls. The structure would require temporary construction bracing to prevent racking until the perpendicular interior frame walls are installed - and they would have to be engineered and built with diagonal bracing to resist racking through the life of the structure. All this would be tricky and expensive, with gobs of diagonal bracing in the way and then trashed when no longer needed. We could see that by installing the interior partitions of pre-cut SIPs as each floor went up, all the temporary bracing could be eliminated and the assembly schedule would be jumped ahead; all adding up to a significant savings for the project. Here we would be capitalizing on the tremendous racking resistance of SIPs.
It seems that I always come back to this theme: just utilizing SIPs in building stick translations which ignore the full range of strengths of the material does not serve the industry or the public fully. By selling SIPs "short" - by merely selling SIPs - we delay the time when SIPs will be the dominant material for combustible construction. The two examples cited above came out of group design efforts that had developers, architects, and panel manufacturers represented on the team. This non-traditional approach to the design process allowed for non-traditional solutions to rise to the top. Don't get me wrong, I've got nothing against building traditions - they are the best response to traditional problems. But these are new times with different, non-traditional problems. SIPs are a revolutionary material that can help solve many of the new issues we face in designing and creating today's built environment. New thinking must come along with this new material. I think we're just beginning to see what SIPs can do.