Frost Protection Depth

[spats]

This may sound dumb, but I have to ask it... I'm designing a generator pad that will be constructed in an area with existing concrete paving, 6" thick. Top-of-pad will be 6" above paving, and I have a frost protection depth of 18". Should the frost depth be measured from the top of paving or bottom of paving? (pad 2'-0" thick or 2'-6" thick?).

 

[JAE]

I would say top of paving.

 

[msquared48]

Agree


Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[mmillerpe]

I agree with JAE.

 

[dik]

Just as a caution... if the paving area is clear, the depth of frost penetration can be greater.

Dik

 

[Stillerz]

For something that shallow, I'd consider the worst possible case.
Like a very practical, experienced professor I had back in the day used to say:
"Concrete...why do we use this S#$@? Because it's cheap!!!"

 

[ACtrafficengr]

What are the soil conditions? You need three things to get frost heave: water, cold weather, and frost susceptible soils. If you have silty soil, I'd go the extra 6". On well-drained gravel or sand, I would not be so worried.

"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

 

[hemis]

Any trees nearby?

 

[spats]

I decided to put the pad on a 6" compacted stone base. I believe that should do the trick. I really don't know what the soil is. This is just an emergency power system being added to an existing building constructed some time ago. I am going to follow-up to at least find out if someone can tell me the type of soil.