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  1. #1

    Default Foundation Drainage

    I know this was a recent topic but I cant seem to peal away the layers without another question arising. Are foundation drains required with a crawlspace home. If they are what are the most common exceptions? In my area about 75% of the homes built over the last 10-15 years have them but in some areas they are not used and the local code enforcement people are on way one day and another way the next. It appears that some code official require them and some do not, the latest comment from today's official is "that was taken out in the 2006 code revision (this was the had code official for the county) Hopefully some of our code gurus will have input...

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    Jeff Zehnder - Home Inspector, Raleigh, NC
    http://www.jjeffzehnder.com/
    http://carolinahomeinspections.com/

  2. #2
    Join Date
    Mar 2007
    Location
    Spring Hill (Nashville), TN
    Posts
    5,851

    Default Re: Foundation Drainage

    Quote Originally Posted by Jeff Zehnder View Post
    I know this was a recent topic but I cant seem to peal away the layers without another question arising. Are foundation drains required with a crawlspace home. If they are what are the most common exceptions? In my area about 75% of the homes built over the last 10-15 years have them but in some areas they are not used and the local code enforcement people are on way one day and another way the next. It appears that some code official require them and some do not, the latest comment from today's official is "that was taken out in the 2006 code revision (this was the had code official for the county) Hopefully some of our code gurus will have input...
    If it was removed then it was a stupid move... Does NC have it's own code or do they use the IRC?

    Proper foundation drainage is required in the IRC... I think it is in 405.1... You have to drain groundwater away from the foundation. This is common sense and just good building practices.

    Scott Patterson, ACI
    Spring Hill, TN
    www.traceinspections.com

  3. #3
    Join Date
    Mar 2007
    Location
    Fletcher, NC
    Posts
    28,032

    Default Re: Foundation Drainage

    Quote Originally Posted by Scott Patterson View Post
    If it was removed then it was a stupid move... Does NC have it's own code or do they use the IRC?

    Proper foundation drainage is required in the IRC... I think it is in 405.1... You have to drain groundwater away from the foundation. This is common sense and just good building practices.
    - R405.1 Concrete or masonry foundations. Drains shall be provided around all concrete or masonry foundations that retain earth and enclose habitable or usable spaces located below grade. Drainage tiles, gravel or crushed stone drains, perforated pipe or other approved systems or materials shall be installed at or below the area to be protected and shall discharge by gravity or mechanical means into an approved drainage system. Gravel or crushed stone drains shall extend at least 1 foot (305 mm) beyond the outside edge of the footing and 6 inches (152 mm) above the top of the footing and be covered with an approved filter membrane material. The top of open joints of drain tiles shall be protected with strips of building paper, and the drainage tiles or perforated pipe shall be placed on aminimum of 2 inches (51 mm) of washed gravel or crushed rock at least one sieve size larger than the tile joint opening or perforation and covered with not less than 6 inches (152 mm) of the same material.
    - - Exception: A drainage system is not required when the foundation is installed on well-drained ground or sand-gravel mixture soils according to the Unified Soil Classification System, Group I Soils, as detailed in Table R405.1.
    - R405.2 Wood foundations. Wood foundations enclosing habitable or usable spaces located below grade shall be adequately drained in accordance with Sections R405.2.1 through R405.2.3.
    - - R405.2.1 Base. A porous layer of gravel, crushed stone or coarse sand shall be placed to a minimum thickness of 4 inches (102 mm) under the basement floor. Provision shall be made for automatic draining of this layer and the gravel or crushed stone wall footings.
    - - R405.2.2 Moisture barrier. A 6-mil-thick (0.15 mm) polyethylene moisture barrier shall be applied over the porous layer with the basement floor constructed over the polyethylene.
    - - R405.2.3 Drainage system. In other than Group I soils, a sump shall be provided to drain the porous layer and footings. The sump shall be at least 24 inches (610 mm) in diameter or 20 inches square (0.0129 m2), shall extend at least 24 inches (610 mm) below the bottom of the basement floor and shall be capable of positive gravity or mechanical drainage to remove any accumulated water. The drainage system shall discharge into an approved sewer system or to daylight.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  4. #4

    Default Re: Foundation Drainage

    Thanks for the input

    Jeff Zehnder - Home Inspector, Raleigh, NC
    http://www.jjeffzehnder.com/
    http://carolinahomeinspections.com/

  5. #5
    Join Date
    Mar 2012
    Location
    North Central Texas
    Posts
    491

    Default Re: Foundation Drainage

    usable spaces located below grade
    Just exactly what is meant by "usable space"? Would that be the synapse gaps in the mind of the author?

    Texas Inspector
    http://www.texasinspector.com
    What the plainspoken man lacks in subtlety, he makes up in clarity.

  6. #6
    Tony Coelho's Avatar
    Tony Coelho Guest

    Default Re: Foundation Drainage

    I second what Jerry said! It depends on soil type.


  7. #7
    Join Date
    Feb 2010
    Location
    Wenatchee Wa
    Posts
    301

    Default Re: Foundation Drainage

    Most homes in my neck of the woods do not have footing drains. Make even more critical that they grade the lot properly. Even with good drainage problems occur from poor slope at the home.

    Compounding that about 50% of the homes do not have and gutter systems.

    Don Hester
    NCW Home Inspections, LLC
    Wa. St. Licensed H I #647, WSDA #80050, http://www.ncwhomeinspections.com

  8. #8
    Join Date
    Mar 2007
    Location
    New Westminster, B. C., Canada
    Posts
    165

    Default Re: Foundation Drainage

    Hi, ALL &

    ** Please remember a crawl space is really just a low-height version of a full basement.

    Who would even think of pushing a basement below ground into the water table without providing a perimeter foundation drainage system ?

    Although there are fools born every minute...


    CHEERS !

    -Glenn Duxbury, CHI

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