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Frost depth of footers

Frost depth of footers

  • To the top of the footer

    Votes: 1 25.0%

  • To the bottom of the footer

    Votes: 3 75.0%

  • Elsewhere. Please explain.

    Votes: 0 0.0%
  • Total voters
    4
jar546

jar546

CBO
Joined
Oct 16, 2009
Messages
12,718
Location
Not where I really want to be
For those with frost depth requirements under the IRC, where do you measure to from planned finished grade?

1) The top of the footer

2) The bottom of the footer

3) Elsewhere (explain)

Let's discuss this please.....

R403.1.4.1 Frost protection. Except where otherwise

protected from frost, foundation walls, piers and other

permanent supports of buildings and structures shall be

protected from frost by one or more of the following methods:

1. Extended below the frost line specified in Table

R301.2.(1);

2. Constructing in accordance with Section R403.3;

3. Constructing in accordance with ASCE 32; or

4. Erected on solid rock.
 
Isn't the idea to make sure that the footing is entirely below the frost depth? I don't have that issue here in the tropics but if I did I would measure to the bottom of the footing.
 
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R403.1.4.1 Frost protection. Except where otherwise

protected from frost, foundation walls, piers and other

permanent supports of buildings and structures shall be

protected from frost by one or more of the following methods:

1. Extended below the frost line specified in Table

R301.2.(1);

2. Constructing in accordance with Section R403.3;

3. Constructing in accordance with ASCE 32; or

4. Erected on solid rock.

Is the footer a footer and the wall a wall or is the footer part of the wall?

 
If the frost depth is 36 inches the bottom of the footing needs to be below the 36 inches, not the top not some point between the top and the bottom only the bottom.Frost has to be able to get below the bottom of the footing before it may cause an issue.Why measure to the top? The footing can be 6, 8, 10, maybe even 12 inches thick. Measuring to the top could require an extra foot of concrete for the entire perimeter of the foundation wall that will serve no code purpose.Do not get hung up on the "foundation walls" wording. The IRC allows a foundation wall to bear directly on the soil without a footing a. Where minimum footing width is 12 inches, use of a single wythe of solid or fully grouted 12-inch nominal concrete masonry units is permitted.
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Since I don't have to deal with it, I'll take your word fot it. So if I were to build where I was told that the frost depth is 36" I would add a foot to that. Ya I know that's a waste of concrete. I figure that if everybody is planning on the frost getting to 36", 37"is not out of the question. Where does it stop? A foot is good.

If I were an inspector in that situation, 36" is apparently all that is required. So I would add only a foot to that.
 
Last edited by a moderator:
I have a patio cover that I purchased to have installed in the rear of my home from Fourseason sunrooms, the engineering calls for at least 3.5" min conc., the inspector gave me a deviation notice that I needed to have footings below frost depth per their county. does this sound right? the code reference they gave me is 2015 IRC R403.1.4.1, I do agrees with the code when it comes to building a heated structure to protect any and all water lines, and waste lines... but this is a shade (aluminum) structure.
 
chipper1966 said:
I have a patio cover that I purchased to have installed in the rear of my home from Fourseason sunrooms, the engineering calls for at least 3.5" min conc., the inspector gave me a deviation notice that I needed to have footings below frost depth per their county. does this sound right? the code reference they gave me is 2015 IRC R403.1.4.1, I do agrees with the code when it comes to building a heated structure to protect any and all water lines, and waste lines... but this is a shade (aluminum) structure.
Click to expand...
Is it attached to the house? If so, the footings must extend to frost depth to prevent frost heave of the footings.
 
If you read the specs and sales literature from Four Seasons, they probably have a disclaimer about compliance with local codes. Whoever pulled the permit for the installation should have verified the requirements. Has the slab been poured already? When you said you have a deviation notice ... was that comments on the permit application, or did they fail a site visit?
 
e hilton said:
If you read the specs and sales literature from Four Seasons, they probably have a disclaimer about compliance with local codes. Whoever pulled the permit for the installation should have verified the requirements. Has the slab been poured already? When you said you have a deviation notice ... was that comments on the permit application, or did they fail a site visit?
Click to expand...
 
there is an existing 4" conc. at this site, and i was given a fail at site for final inspection,... i have stamped engineering that states that these structures can be installed on existing 4" conc. but the local would not bend
 
chipper1966 said:
there is an existing 4" conc. at this site, and i was given a fail at site for final inspection,... i have stamped engineering that states that these structures can be installed on existing 4" conc. but the local would not bend
Click to expand...
I have seen many of these FourSeason attached patio covers. In the general notes, it will refer to the local design criteria. Yes, they do have a detail showing attachment to a 4" slab. That said, it is not code compliant for an attached patio cover. The FourSeason plans has many details, and the wrong one was selected. If it is attached to the home, code requires footings to extend to frost depth. Take a look at the General Notes, and it has a note about this as well; they tell you to extend to frost depth.
 
chipper1966 said:
i have stamped engineering that states that these structures can be installed on existing 4" conc. but the local would not bend
Click to expand...
The problem is … somebody in the design department of Four Seasons designed the structure and the “minimum” foundation that would hold it up. And they attach that same design to every structure they sell in every city and every state. There is no way that designer can verify his design will meet code in every city in the country, so they add a note in fine print that puts the requirement on the buyer. That’s you.
 
The only way you are going to win is if your contract with the local Four Seasons dealer and the installer says something about the scope of work and installation shall comply with all local building codes. In that case it’s on them to do it right. But it’s possible there is a sentence in your sales contract that says their price does not include permit fees or obtaining the permit.
 
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