I was recently reading a post from
www.AskCodeMan.com that basically states (I assume) that
even though the floating deck is exempt from frost protection, the blocks still need to placed at least 12 inches below the undisturbed ground surface to meet R403.1.4. Would that be correct?
Message as posted on
www.AskCodeMan.com:
From the IRC.
- R403.1.4 Minimum depth.
All exterior footings shall be placed at least 12 inches (305 mm) below the undisturbed ground surface. Where applicable, the depth of footings shall also conform to Sections R403.1.4.1 through R403.1.4.2.
- - 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: (Jerry's note: These exceptions are exceptions to "Frost Protection".)
- - - - 1. Protection of freestanding accessory structures with an area of 600 square feet (56 m
2) or less, of light-framed construction, with an eave height of 10 feet (3048 mm) or less shall not be required.
- - - - 2. Protection of freestanding accessory structures with an area of 400 square feet (37m2) or less, of other than light-framed 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.
Notice that the exceptions apply to "R403.1.4.1 Frost protection.", not to "R403.1.4 Minimum depth.".
Thus, the minimum footing depth is "at least 12 inches (305 mm) below the undisturbed ground surface".
I have not seen any of those footings which are designed sufficiently large enough to extend "at least 12 inches (305 mm) below the undisturbed ground surface".
You are correct in that free standing decks do not need to be protected from frost.
__________________
Jerry Peck, Construction / Litigation Consultant
Construction Litigation Consultants, LLC (
www.ConstructionLitigationConsultants.com )
www.AskCodeMan.com
