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Standing water in crawlspace

Arkansas home built in 1930, crawlspace is 3 feet in front of house and 10 inches at back. Our floor joists are only inches above dirt in back of house. The limited space does not allow for access to plumbing or great visibility.
During heavy rains we get pools of water in the crawlspace. There is visible damage on our bearer joist.
Clearly we need to rectify. Question is do we dig a french drain on outside perimeter to divert water or dig out and lower crawlspace level for access and to create distance between moisture and wood? Or both?

A. Spruce
Re: Standing water in crawlspace

What you do depends on what the problem is.

An 80 year old house would not have lasted this long if sub area water were a constant problem, which means it's a relatively new development. My suspicion is that either landscaping or water handling at the house has compromised drainage.

Make sure that the ground falls away from the house in all directions and that downspouts are directed at least three feet away from the house. My preference for downspouts drains is to direct them into drainage systems (3" corrugate drain line ) that runs to municipal collection systems.

You also mentioned that some of the framing is just inches above the dirt. Excavate that area to a minimum of 8", though 12" or more would be better and 18" optimal. Don't undercut foundations with excavation, cut the dirt at approximately a 30 to 45 degree slope from the side of the foundation to the bottom of the excavation. Leave the dirt undisturbed in at least a 3 foot diameter around central piers OR resupport house, dig out dirt and set a new pier and post.

Re: Standing water in crawlspace

Thanks for your reply. About 10 years ago, the little old lady who lived here before us, had a huge HVAC unit installed with giant duct work. The company had used the old gas floor furnace grates for return air ducts. They dug a hole to accomodate an approximately 3 foot cube. I noticed the insulated sides of the box where moist and upon further inspection (peeling back the black fabric) I found a 4 inch rust water line where water had obviously been pooling and draining for quite some time. When we removed it and redirected our return air duct we could see that some of the duct work to the back of the house was sitting on the ground and that our bearer joist was wet and had a section that had already cracked away. Now I'm concerned about termites and mold.
I appreciate your direction in digging out the back half of the house, wasn't sure how to avoid jeopardizing foundation. It's a long haul of digging bit by bit, the portion of the house in question is about 1600 square feet and only about 8 inches high. We're talking belly crawling. Not pleasant or easy. Thanks.

A. Spruce
Re: Standing water in crawlspace

I recommend consulting with a local foundation expert who can give you specific remediation advice about your situation. You may not have to do anything under the house, as long as there is no earth to wood contact. Excess water in that pit dug by the HVAC company could just be a matter of a seasonal high water table, and not necessarily a drainage problem, though good drainage around the house will improve conditions under the house.

The internet is a good place to start to find information, but it is not a replacement for local professional tradesmen.

Derek Engle
Re: Standing water in crawlspace

For a very detailed explanation on your issue i would visit http://crawlspaceinfo.com

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