Replies

1. 
   Piffin | Jun 08, 2003 03:30pm | #1

   stands for Structural insulated panel.

   Skins fully adhered on both sides is what makes it structural.

   No way to do that in a homemade version.

   But you don't need a structural panel for underskirting. You just need to fasten foam panels to plywood or T-111

   .

   Excellence is its own reward!

2. 
   bill_1010 | Jun 08, 2003 05:55pm | #2

   you really dont need SIPs since your "lodge" is probably on blocks.   Why not consider foam, either sprayed in place or in sheet form.

3. 
   tkiser | Jun 08, 2003 09:26pm | #3

   Nothing wrong with using ridged foam and CDX plywood and foam.

   Tim Kiser

4. 
   peajaybee | Jun 09, 2003 05:20am | #4

    I knew better, I shouldn't have given out so much information, it always colors the responses in ways I hadn't intended or anticipated.

   Piffen, I disagree with your statement, but I'm no engineer.  I believe the plywood skin adds all the "structure" to the panels, the foam only serves as a spacer/insulator IMO.

   I know that this application doesn't really need much structure, but I'm curious as to how they are really built.  My feeling is that I can glue up some isocyanurate or polystyrene panels to treated plywood, and voila' have an SIP.  Specifically, I'd like to know what type of glue to use, and if in fact it would work.  I have a few other small projects in mind, that I'd experiment with too, such as the well house, and an enclosed porch.  I'm putting this in an area that can be very cold, it is in the mtns of Northern NM.  The skirting is to a point where it has to be replaced anyway, and this seemed like a good solution.

   Birddog

1. 
   Bruce | Jun 09, 2003 05:44am | #5

   I'm no engineer either, in degreed terms, but I have engineered enough composite panels in balsa or foam core, with FRP skins, to know that Piffin is right, and you are not.

   It is the resistance to peel or shear loading that makes the skins in a panel do their work, i.e., the skins must be kept in the same relationship to each other, in all axes.  You could try to put some stickum on some foam and your choice of skin, and you would end up with an IP, not a SIP. 

   In the case of EPS panels, the manufacturers spray or roll a coat of a very specific adhesive onto the parts of their sandwich, and then heat cure them under pressure.  Those panels are then subjected to a regime of standard tests to determine if they can resist the loads they claim to.

   In the case of urethane panels, the liquid urethane is sprayed onto 2 skins which are held a fixed distance apart as the foam expands and cures.  This is the same base material used in Gorilla Glue, and it is extremely strong.

   So go for your IPs to insulate your skirt, but don't try to peddle any of them to me for structural purposes. Formerly BEMW at The High Desert Group LLC

2. 
   Piffin | Jun 09, 2003 06:27am | #6

   I hate being right all the time, I have to make a mistake every day to stay humble.

   But this isn't it. If you think ply panels can do the job without being specifically sandwiched, try building a house with just plywood and no studs. See how well they take the load of the second storey and roof. It's that sandwiching action that makes them what they are.

   It is similar to the construction of an I-beam. Every component is in a specific place for a specific reason, in resisting all the forces that act on it..

   Excellence is its own reward!

1. 
   CAGIV | Jun 09, 2003 06:41am | #7

    

   I hate being right all the time, I have to make a mistake every day to stay humble.

   But this isn't it

   LMAO, you're too funny.Never be afraid to try something new. Remember, amateurs built the ark, Professionals build the Titanic.