SIPS

[spats]

Is anybody out there familiar with SIPs?: Structural Insulated Panels. They consist of OSB facings with an expanded styrene core. They are used for walls, floors and roofs. The walls are often load-bearing no less. Are there studs built in?

I did find

http://www.sips.org,

and there's some information there, but not much. Looks like the system is a work in progress. The “Design Guide” I downloaded from the site is blank on the topic of shear walls and diaphragms.

I have a potential customer who wants to use SIPs for a four story hotel! I can't see it... looks scary to me!

Any comments from anyone who has used the product would be greatly appreciated.

 

[BadgerPE]

We used these on a timber framed house once for roof panels. The built-in joist spanned between timber framed rafters. If I remember right, they put the roof on in about a day so they are very good for speed of construction. We went with these because they wanted to expose as much timber as possible.

I will look and see if we have any manufacturer info from this project.

 

[msquared48]

Premier Building Systems in the Puget Sound area used to manufacture these panels, and I have used them on one and two story residential structures. However, I share your concern about a four story structure, particularly in the area of shear capacity.

Premier was different, but many of the manufacturers do not rate their panels for shear. Typically they use 2X4 studs at the periphery which would limit their shear capacity by code unless the system is rated.

Honestly, I cannot remember if they have interior studs, but the plywood is glued to the foam interior, We cannot rely on glue alone structurally, so, another reason to use only a rated panel for shear.

Mike McCann
MMC Engineering

 

[spats]

Thanks for the feedback guys. I' also interested to know what the design process is. Are they treated the same as any other delegated engineer? The use of the product could be so extensive that I feel like I would lose control of the design process. Gravity only components are one thing. I don't feel like I can designate diaphragm and shear wall design responsibilities to others.

Mike, did Premier provide you with shear capacities and details for your design?

 

[msquared48]

Spats: Yes, they did. Just don't know if they are still in business...

Mike McCann
MMC Engineering

 

[SoDakEng]

If you supply the gravity and lateral load to the SIP supplier, they can design the panels. You would still design the interior wall framing and floor diaphragms, since SIP’s offer little advantage as interior walls and flooring members. This would still give you a great deal of control over the design. Keep in mind that a lot of SIP’s are not approved for seismic D locations. The racking shear strength and uplift of the panels will most likely be your largest hurdle, I would recommend that you contact the SIP supplier to discuss the project.

 

[a2mfk]

A few years ago I did several SIP jobs in Florida with a manufacturer out of Michigan. I was the EOR for the whole thing, using their data/spec sheets for the basic load capacities, and working with their engineer to guide me through the process. One of the projects was a very large multi-story house on piles in a high wind area, which was quite a challenge to say the least. Like with any wood framed house, the devil is in the details: uplift connections, shear connections, general proper load path. We had to add extra 2xs in the wall in a lot of places just to get the uplift connections and direct lateral loading to work. Lots and lots of detailing the wall panels, almost like you would do for concrete tilt panel construction. Then the SIP manufacturer did shop drawings based on my panel drawings.

But that project was a very unusual, non-cookie cutter custom house. A big box hotel with a very repetitive floor plan may be a good candidate for SIPs. For uplift I would go with a continuous anchor rod or tie wire system to eliminate the wall-floor-wall tie down connections, make your life a whole lot easier. I do not see being able to rely on the SIP manufacturer for anything other than standard shear and lateral loading data, I would want to be in control of all the other detailing to make sure it is done right. Either way, something goes wrong, you are getting dragged into it.

Not sure I would want my first SIP job to be a 4 story hotel though!