when to ignore frost depth? 1

[delagina]

I have an equipment that is normally supported on slab on grade.
The site we are working on is located in the north near Minnesota.
what are my options for foundation in this case?

 

[delagina]

dik, do I need to specify the insulation thickness or just the R value?
I'm looking at a go-by and it calls out the insulation as 2" Rigid Insulation, R-10
Not sure if the go-by is calling out the insulation correctly.

In your example, you called out the insulation as Type 4, you didn't specify any R value

 

[atrizzy]

You'll need to specify the insulation thickness and projection outside the foundation area.
Your geotechnical engineer should be able to help you with this, and you should have them review your design prior to issuing.

 

[delagina]

this guide only computes for the Rg value and projection and not for thickness of insulation.
Why do you need to specify the thickness if you already specified the R value?

http://liteform.com/wp-content/uploads/2017/04/FPSF-Guide-Revised.pdf

 

[dik]

as atrizzy notes, generally the thickness. and the extension beyond the stiffened edge. Often the insulation thickness can be reduced beneath the building due to the protection offered by the structure unless you have a shed without doors.

If the building is heated I have section detail that shows the insulation wrapping up the edge of the stiffener. Dow had a really good publication on insulated buildings.

Dik

 

[oldestguy]

All this fuss and commotion when one factor has not been mentioned. What have been the problems in the past at the site? Maybe no big deal.

 

[TLHS]

I've found that there's no real attempt made to justify less frost protection. I work in pretty cold climates, and trying to get geotech opinion on frost susceptibility is like pulling teeth. I get it, because it's not a completely cut and dry criteria, but it's pretty frustrating.

 

[JedClampett]

I've seen local building code amendments dictating foundation depth.