Written by: Bryan Osborn AIA LEED GA
During a design ‘charette’, when I was much younger man in Architectural School, when one was caught with an un-buildable detail in our design, we would pull out-of-our-hat this miracle material called ‘Glip~sight’. You know, it could cantilever 200 feet, support 80 stories with only 1/2″ thick walls, super-insulating at R-30/inch, and oh-yeah, it was waterproof! In short, one material that provided all your solutions.
Well, the 2030 Challenge is on and here in California we have officially begun the CalGreen era where NetZero buildings are the ultimate goal. Throwing a note on the plans – “2x6s @ 24″ oc with R19 batt“- just isn’t as easy a solution anymore. Now, you’re back between a rock and a hard place squeezed from the left with Efficiency! and from the right with Sustainability! and needing a solution to your NetZero world. <Hint> Glip~sight is not available yet.
The good news is, if your project is wood framed, the solution has been around for awhile- like over 40 years. It’s tested and proven on thousands of structures over many years. A building product that can get your commercial or residential project closer to NetZero than any other single construction product out there, and do all that, while providing incredible structural strengths. (like 720 & 920 plf in SDC DEF for shearwalls) The solution is called SIPs, the acronym for structural-insulated-panels.
I think of SIPs as an improvement on framing not an alternative system of building. SIPs are just another framing product that meshes with typical framing techniques. It’s not that big a departure from the norm as typical lumber is used to ‘sew’ the SIPs together and all your floors and interior walls are all typical wood framing. This is all good because the available skilled carpenters and contractors do not have a steep learning curve to work with SIPs and neither do you as an Architect. Everyone can appreciate working with a flat dimensionally stable product that provides for higher quality finishes than wood framing. So now by using SIPs we have better strength and quality.
Some SIP structures have been tested to 0.05 ACH passive (air-changes-per-hour). That’s really tight, and one of the primary reasons SIPs are so efficient. Remember – it’s not just insulation! A big concept to learn is that now you are building a super-tight structure that involves additional thought in selecting mechanical systems, like heat exchange units, and maintaining fresh air quality. Fortunately currently there are a lot of great choices of high-efficiency mechanical components available. Because your heating and cooling loads are less you can downsize the mechanical equipment saving $$$ for your client during construction and every single month thereafter – for the life of the building. So now by using SIPs we’re talking better strength, quality, and efficiency all rolled into one solution.
For the Architect to consider during the design phase – your wall widths change. SIPs typically are only the exterior shell so mainly the exterior walls & roofs are affected. Premier SIPs are manufactured for use with typical lumber sizes. For instance a 6″ SIP has a 5 1/2″ EPS core to accommodate a 2×6 vertical spline or horizontal plate. (Consult PBS Design Manual) So instead of having a 5 1/2″ rough wall framing outline drafted on your plans the SIP rough framing is approx. 6 1/2″width. Not a big deal, but this dimensional width increase can add up if you are concerned about final finish dimensions and clearances. The panels themselves are manufactured in 8 ft x 24 ft panels, 4″ to 12″ thicknesses. That means your highest walls and the longest roof runs from ridge to eave can be 24 feet. Tall walls and long runs may require additional posts & framing within the SIPs which your Structural Engineer can determine.
Finally from your Architectural plans (PDFs) a set of panel shops are created. These are similar to truss or steel shop drawing, where the specifics, like rough openings, hold down posts, and other required structural components are incorporated into the SIP package. Here at Premier, we work with the Structural Engineers and Architects during the shop drawing process to make sure everything is incorporated into the panel shop drawings. Typically these panel shops in PDF format go back and forth a couple of times for verifications and redlines. Once we receive the customer’s final approvals we custom fabricate your project based on those shops. What’s that? You want a hundred? No problem we can do that. SIPs make your project Stronger, Straighter, and Greener.
For those with inquiring minds: A charrette (pronounced [shuh-ret], often Anglicized to charette and sometimes called a design charrette) consists of an intense period of HYPERLINK “http://en.wikipedia.org/wiki/Design” o “Design” design activity. – Wikipedia