SIP’s and Sticks

 

Studio Boise, LLC was recently commissioned to design a modular home that could be assembled in an average of 2 days.  In decades past, this would sound like we were designing a mobile home trailer.  Today, however, modular home design  can have as intricate a floor plan, as many surface treatments, and as much style as any traditional stick frame home.

 

Stick framing is what you usually see when you drive by a construction site just a few days after the foundation has been finished.  Stick framing is the skeleton of most buildings with 2×4 or bigger lumber or light gauge steel standing up every 16″ along every wall both interior and exterior of a house.  Once the “sticks” or studs, (as they’re called in construction) have been nailed in place, insulation is laid in between them, covered with sheathing, covered with a vapor barrier, and then covered with a wall surface.  The great thing about stick framing is that literally  every contractor knows the method, it’s one of the more economical ways to frame, and it is easy to build a home with a floorplan that jogs in and out where ever you would like.  The down side is that even though contractors are very efficient in this method, a fair amount of scrap material is wasted, and it takes a lot of time to frame, insulate, wrap, and cover every wall.  Time = money.

 

Enter SIP’s.  Structurally Insulated Panels are exactly what their name implies.  They are panels that usually come in 4′ wide by 8′ to 12′ tall panels, and they are structural meaning they can carry weight, and they are insulated.  SIP’s usually look like an ice cream sandwich wherein the cookies are 3/4″ thick boards, and the ice cream is a Styrofoam insulation.   There are various types of SIPs depending on the manufacturer you choose.  For example, RayCore SIP’s have wooden studs inside the insulating foam, and they are only as strong as the wooden studs inside them.  RayCore panels do not connect directly to eachother; instead, they stand side by side and are held in place by the same top and bottom plates (long horizontal pieces of wood on the floor and on top of each panel).   Another brand, Precision Panels, has the more typical ice cream sandwich style SIP.  These connect to eachother as well as to the top and bottom plates.

 

No matter the type of SIP that you choose, they all seem to have the same ups and downs.  On the down side, if you need a panel that falls short of the 4′ module, then you need to pay extra money for the cut at the factory.   Angled SIP’s acting as vaulted roof spans are usually limited to around 15′ or less if you expect more than several inches of snow each year.  Beyond that, you have to frame the roof using traditional stick frame methods and add the panels on top as insulation only.  SIP’s are also difficult to use on a complicated roofs.  Another big consideration when using SIP’s is the location of plumbing.  The foam in SIP’s can be effected by moisture, so any plumbing that needs to go up a wall must be encased in a chase, which adds expense.  SIP’s are also more expensive than the lumber used in stick framing.  I’ve seen SIP costs range from $4.00-$7.00 per square foot meaning that you spend anywhere from $130-$260 for every 4′ of wall that your custom home plan requires.  Obviously, this is more money that the simple 2×4’s used in stick framing cost over 4 linear feet.  However, this is where the savings are highly debated.  Because the SIP’s include the insulation, often a vapor barrier as well, and sheathing, and tend to give your home an insulative R-value from 20-36, they become more appealing.  Add to this the fact that even a construction team that is new to most SIP systems can frame a 2,000 square foot home in less than a day, and now you have saved a couple days of construction costs.  With such high R-values, SIP manufacturers promise that you will break even with the extra cost of the panels in a matter of years by saving significantly on heating and cooling expenses.  Some SIP’s such as RayCore panels are fire-retardant, and will save you money that you would have spent spraying expensive fireproofing material throughout your home’s framing (if you live in an area requiring fireproofing).  Using SIP’s also gives you better air quality control, and is a great choice for DIY home builders without professional experience.

 

As a designer, my priority is my client’s priority.  At Studio Boise, LLC we let your priorities dictate the building method that will be best for you.

 

Here is a home design quiz to help you decide what building method is best for you:  (Yes/No)

1.  Do you live in an area of extreme temperatures? Y/N

2.  Is reducing your energy bill among the top 3 priorities for designing your new home? Y/N

3.  Are you interested in building your own home? Y/N

4.  Is your new home design a one story home  on a relatively flat site which has easy access for a crane? Y/N

5.   You don’t want many bay windows or jogs in your new floor plan. Y/N

6.  Do you need your Boise home to be built in a month or less? Y /N

7.  Is green design one of your top 5 priorities for your new home? Y/N

9.  You do not need any large vaulted ceilings.  Y/N

10. Your dream home does not have any curved walls. Y/N

 

If you got 5 or more ‘Y’s, then you should consider using SIP’s for the construction of your new home.  In you got 6 or more ‘N’s, then traditional stick framing is probably the way to go.

Good luck!

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