# Crawlspace clearance



## Sifu (May 8, 2012)

I got a call from a guy this AM who wants to install a wood floor over an existing slab.  The clearance from the joists to the top of the slab will be 8".  The slab will not have an have an intact vapor barrier after being cut for footings and piers.  He can use treated lumber for the floor system or separate the ground with a continuos vapor barrier to satisfy 319.1.  He can cut an 18" x 24" floor opening to satisfy 408.4.  He could ventilate it or condition the crawl.  Anything I am missing.  I worry about access for personnel but it would be no different than accessing a slab right?


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## Dennis (May 8, 2012)

This is done regularly where one has a carport and they convert it into a room.  I have never seen access required.


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## pwood (May 8, 2012)

no access required... ventilation would be a plus, no junction boxes or plumbing that requires maintenance or accessibility.


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## globe trekker (May 8, 2012)

Ventilation required per R408.2, 2006 IRC, if there is any exposed earth underneath.


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## Sifu (May 8, 2012)

The old carport slab will be cut for footings and piers so there will be some exposed earth.  I told him he needs continuous vapor barrier or treated lumber with the reduced clearance.  There will be some plumbing but we discussed excavating a portion of the existing slab at that location down to an accessible depth and accessing it from the outside.  That way anything that would need work is accessible and at least the rest would be "viewable" with a good flash light (thinking home inspection, termite inspection etc).  It will definately be vented.  I think it will work out, just wanted to see if I was missing anything big.


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## brudgers (May 9, 2012)

Plumbing and electrical are placed under slabs on grade every day.

  There's no reason to prohibit them in a crawl space.

  Sometimes servicing services just sucks.


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## pwood (May 9, 2012)

brudgers said:
			
		

> Plumbing and electrical are placed under slabs on grade every day.There's no reason to prohibit them in a crawl space.
> 
> Sometimes servicing services just sucks.


 no problem with plumbing and electrical in this underfloor area as long as there are no junction boxes that need access, or screw together traps , cleanouts not accessible, you get the jist?


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## globe trekker (May 10, 2012)

> I got a call from a guy this AM who wants to install a wood floorover an existing slab. The clearance from the joists to the top of the slab
> 
> will be 8".


How is this amount of limited space going to be compliant for anyone

trying to service / repair / replace any of the systems (i.e. - elec. & plbg)?


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## brudgers (May 10, 2012)

globe trekker said:
			
		

> How is this amount of limited space going to be compliant for anyone trying to service / repair / replace any of the systems (i.e. - elec. & plbg)?


  More so than if there was a slab on grade.


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## Sifu (May 11, 2012)

I'm comparing the accessibility for service to that of slabs and going one better by locating anything that would need service in an area of increased clearance.  He will limit the amounts of any items in the space as much as possible.  This is an accessibility project, not by code but by choice for an aging owner, that is why they are trying to keep it as low as possible (for lower ramps and stair avoidance).  I think we are mostly all on the same page here.


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## mark handler (May 11, 2012)

http://www.sandiego.gov/development-services/industry/pdf/bnl23-04.pdf

This is an old Building Newsletter from the City of San Diego

But has some ideas on the subject


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## Sifu (May 11, 2012)

Thanks Mark, good article, I love pictures.  They keep me from sounding stupid by limiting the amount of time I spend speaking.


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## Francis Vineyard (May 11, 2012)

The code requires access; does not imply the space needs to be accessible for servicing.  The visual inspection can be other code items in need of repair to damage not limited to wood; termite or other deficiencies.

Francis


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## peach (May 12, 2012)

he'll probably have plenty of access... my guess is that the wood floor will warp frequently enough that he'll be replacing it.

It's not a crawl space (unless someone is really thin) - it's an elevated floor.

I'd condition it (one little supply, one little return) to keep it dry and I'd probably put styrofoam insulation on top of the slab.


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## Sifu (May 14, 2012)

I will run the conditioned idea by him.  I think that might be a good alternative in this case.


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