Solar kiln floor insulation???

[Nebraska]

Leaning towards 3/4 inch foil faced polyiso..  Just wondering what feelings were and others choices had been.  I could go 2 inch if need be.  Building on top of 5/4 recycled deck boards. 

[Southside]

Isn't that the while open pore stuff?  I would be concerned with water getting into it. 

[Nebraska]

Well I didn't think it was, I thought it kind of looked like spray foam between aluminum foil. My plan was to sandwich it under some plywood then maybe use a cheap waterproof closeout click vinyl for the floor if it will take the heat. Or maybe cheap ceramic tile on cement board. At the rate I am moving maybe it will be done by next year. 

[blackhawk]

I would go with the 2" thick foam.  That is what I used beneath the concrete for my DH kiln.

[K-Guy]

@Southside
@Nebraska
It is moisture resistant, so I would recommend a vapor barrier between it and the floor. Use 2" of the polyiso.

[scsmith42]

I used 6" of closed cell insulation in the floor, walls and doors of 3 of mine.  They get hotter in the summer than my 4th solar that has 4" poly-iso insulation.  

[Nebraska]

6 inches may (ok will)...require me to noodle on my design a bit more. I was thinking 3.5" in walls etc. 

[scsmith42]

Re wall thickness, it depends upon how cold your climate it.  In my area I'll have solar kiln temps over 100 degrees in all but 2 months or so of the year (in my 3 kilns with the 6" insulation).  In the kiln with 3.5" insulation, it's more like 8 months of the year.

[doc henderson]

Do your thing @Nebraska.  as you get thicker there is less bang for the buck.  as Gene W told me, "It is only a solar kiln".  I think he knew I was making it too hard.  I have still not built my first trying to make it harder than it has to be.  

[farmfromkansas]

I used a welded pipe frame for a base, put some straps sticking up to bolt the floor to, then used 2x6 floor frame, turned it over and put plywood under the floor frame, turned it over and bolted the floor to the pipe frame, put 2 layers of r-11 insulation in the floor frame, put plastic down over the top, then layed t&g flooring.

[Nebraska]

Well my base is two REA poles squared up, with laminated 2x10 beams on 16" centers with a layer of recycled 5/4 deck board that were too good to haul to the land fill.  It's over kill, then insulation with some sort of plywood floor. Walls haven't been decided yet. 

[Nebraska]

I just went with an inch and a half of foam insulation in the floor.  Had a nice sunset. 
Made a little progress. 


not sure what I did to underline the text above. Just happy to get the pictures posted. 

[Nebraska]

Well it was underlined in the preview.