Announcement

Collapse

Plan Review Services

Advanced Code Group (ACG) has been performing plan review services for municipalities, architectural firms, third-party agencies, contractors and code officials for over 10 years with great success and response. We would be happy to assist you with your I-Code plan review needs, whether on a limited or full time basis. Plan review is performed by several experienced inspectors, certified as plan reviewers in different disciplines. We offer expedited plan review services electronically. This has been a well received process that eliminates reprinting of drawings. At the end of plan review, you have the option to accept an electronic stamp on the plans or submit the final, approved drawings for traditional stamping with return via FedEx. Why print, submit then print changes and submit again when this can be done just once?

We will always do our best to work within your budget and allotted timeframe. Feel free to contact our office at 1-877-223-4462 or email us at codes@inspectpa.com for further information or just to discuss your needs.

Thank you,

Jeff Remas
Advanced Code Group
www.InspectPA.com
See more
See less

Frost Protection of Foundation/Footing

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Frost Protection of Foundation/Footing

    Below is the code section from IRC 2009.

    If a municipality deems the frost depth to be 36". Does that mean that the foundation wall must extend below 36" or just the bottom of the footer?

    It is our interpretation that the foundation wall must extend below the frost depth of 36" which means the top of the footer can never be any shallower than 36" to the top of it. The thicker the footer, the deeper you must go.

    How do you interpret this?


    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.
    Exceptions:
    1. Protection of freestanding accessory structures
    with an area of 600 square feet (56m2) or less, of
    light-frame construction, with an eave height of
    10 feet (3048mm)or less shall not be required.
    2. Protection of freestanding accessory structures
    with an area of 400 square feet (37 m2) or less,
    of other than light-frame construction, with an
    eave height of 10 feet (3048 mm) or less shall
    not be required.
    3. Decks not supported by a dwelling need not be
    provided with footings that extend below the
    frost line.
    Footings shall not bear on frozen soil unless the frozen
    condition is permanent.
    Admin

  • #2
    We take it to the bottom of the footing, or pier, or whatever.....because the footing is the support for the wall...if everything is smooth nothing should be "grabbed" and heaved by the frost, and it should not get under the footing...
    Boy it's hot!.....And where are we going in this handbasket?

    Comment


    • #3
      Bottom of a Footing with 2" key.

      Comment


      • #4
        Just the bottom of the footer (footing) for any community I've ever built in.

        mj
        If the head goes through, the rest can too. - Yankee

        Comment


        • #5
          "Bottom @ Footing" is how it is enforced here, and how every structural engineer I have ever worked with specifies the frost-protection for footings. Not to say that just because everybody else does it this way, that it should be that way, but even the ICC engineers I have worked with view it this way.

          Comment


          • #6
            But,

            The code specifically says Foundation Wall and ....extend below the frost line.

            How can a foundation wall extend below a frost line if the top of the footer is above the frost line?
            Admin

            Comment


            • #7
              From the 2009 IRC, Table R301.2(1): The frost line depth may require deeper footings than indicated in
              Figure R403.1(1). The jurisdiction shall fill in the frost line depth column with the minimum depth of
              footing below finish grade.


              Your jurisdiction will have to define the depths that they want to be used.

              Has your AHJ done this?


              .
              Please pray for Wilson ("Daddy-O") and his family!


              Comment


              • #8
                Our jurisdiction did. 36" is the frost depth in most. 42 in others
                Admin

                Comment


                • #9
                  Some foundation walls don't even need footings. Piers don't have footings. The point is, the bottom of the built system should be low enough to prevent frost from getting underneath.

                  Comment


                  • #10
                    Frost depth is 42" here. I measure 42" from the top of the footing.

                    Comment


                    • #11
                      Originally posted by Mac View Post
                      Frost depth is 42" here. I measure 42" from the top of the footing.
                      Yes! That works
                      Admin

                      Comment


                      • #12
                        Originally posted by Yankee View Post
                        Some foundation walls don't even need footings. Piers don't have footings. The point is, the bottom of the built system should be low enough to prevent frost from getting underneath.
                        Grade beams come to mind.

                        Hopefully this will help some, from the 2006 IBC Commentary, Section 1805.2.1 (Frost Protection): "...A common method of accomplishing this is my placing the footing bottom below the frost line." (P 18-12)

                        Comment


                        • #13
                          Originally posted by Yankee View Post
                          Some foundation walls don't even need footings. Piers don't have footings. The point is, the bottom of the built system should be low enough to prevent frost from getting underneath.
                          Yes, Foundation walls without footings must be below the frost depth, the code specifically says that piers must extend below the frost depth.

                          The point is that the language of the code requires that foundation walls extend below the frost depth. So when you have a footer, the top of it must be below frost depth.

                          It does not matter what is "customary" in your area if you have adopted the codebook as written. It says what it says.
                          Admin

                          Comment


                          • #14
                            Here the frost line depth is set at 24",(meaning thats a safe depth before frost becomes an issue). So when asked by Mr. contractor; "How deep do the footings have to be"? They are not talking about the walls, they want to know how deep to make their trench to the bottom of the trench.

                            12" high footing (table R403.1) + a 24" frost depth requirement (established by code and approved by ordinance) = a 36" deep trench, this is the contractors answer.

                            We have a general rule in our area if your live near US36 Highway, your frost depth is 36" which works out so far. Most spread footings here are 8" thick and 12" wide.

                            pc1

                            Comment


                            • #15
                              Originally posted by jar546 View Post
                              It does not matter what is "customary" in your area if you have adopted the codebook as written. It says what it says.
                              In your experience, is frost protection a bearing issue? In my limited experience, a foundation wall bearing on a footing, the bottom of which is below the frost line, is not at risk of heaving...unless there are significant climate changes due in the near future. The code also says that foundations shall be built on undisturbed, compacted fill material or CLSM. It doesn't say they can be built on footings. ;)

                              In addition, the Figure 1805.4.6 of the 2006 IBC indicates the bottom of footing below the frost line, not the top of footing, or bottom of foundation.

                              Comment

                              Working...
                              X