Crawl space moisture/water removal
 

A few weeks ago a broken drain, which we immediately noticed, caused a bit of flooding in the 1300 square foot crawl space of our 1965 house. About two and a half years ago, our home inspector crawled under our 1965 house and gave the crawl space a clean bill of health before we bought it. Well, he was kind of an idiot. After having the leaking pipe repaired, we were made aware of the fact that our crawl space is:

Full of standing water that isn't from the pipe breaking...

Has several layers of plastic vapour barrier, and water is trapped between the layers...

The vapour barrier is pulled away from the foundation walls, is bunched up, and is holding water, growing mosquitoes, mold, and who knows what else...

Several wood posts and some beams have been obviously replaced...

The posts which have not been replaced had plastic bunched up over the piers and halfway up the posts, exposing wood directly to moist soil by bagging them up together...

Nearly half the posts holding up the raised floor are so rotten, that you can stick a finger through them...

There is clear evidence of maybe 8 inches of standing water left on the old posts, and no such water lines on the replacement posts...

Of course, there is the somewhat unpleasant sewer smell that haunts the house now, but it's obviously to me that water has been, is, and will continue to be a problem in the crawl space. It's been brought to my attention that half the crawl space "vents" are also, in actuality, "drains" that excel at directing water from the concrete skirt around our home in to the crawl space. The question is, what do I do besides pay someone to clean up the space and put down new plastic?

A sump seems like it's in order. What about running a drain around the inside perimeter of the foundation to handle ground water and direct it to the sump? How would that best be done? I'm too claustrophobic to go under there and do it myself, but I need to know the right way so that I can make sure whoever I hire to do it is doing it right.

I actually looked in to the encapsulation route, and I like what I saw, but the 18K price tag is just not in our budget at this time. On the other hand, it does seem like the only way to eliminate the crawl space vents that sit below ground level and catch water. Some guidance would be greatly appreciated.

Putting plastic down serves no purpose in a flooded crawl space. You need to set up some sort of water removal system. What the requirements are depends on an on site inspection as to the exact conditions.
Post some photos of the crawl space and the vents.
How much space between the dirt and the floor joists?
Ron

Indeed it does not do any good to have plastic under there at this point.

Photos may not show much, but there is about 3' minimum between the dirt and the bottom of the floor. In terms of head height, it's not an awful crawl space.

There are five vents total between three walls (Shown in red). The vents are typical 8"X16" rough openings framed with 2X lumber and screened. Vents 1 and 2 on one wall are fully exposed, and vents 3, 4, and 5 are all blocked significantly by concrete slab outside the house, leaving open air space of about 8"X1". The crawl space entrance (shown in blue) is equipped with a large grate that should allow air flow, but with the blockages present on the other vents, air flow is not going to be good.

Is the dark spot on the support post a high water mark? The vents blocked by concrete have no real function. There should be window wells around them to allow for ventilation..
Is the water a seasonal thing?
Does the water fill up the crawl space from ground water up under the crawl space or flow in through the vent openings? Or both?
If it initiates in the crawlspace, I'd regrade the crawl space area. Dig a shallow trench around the perimeter graded to a corner. Install a perforated drainage pipe covered in a sock. Line the trench with landscape fabric with enough to cover the top after the trench is filled with gravel. Lay the pipe on a layer of gravel and then cover it over with additionaL stone. Wrap the landscape cloth over the gravel so the dirt doesn't clog the gravel.
In the low corner install a sump tub and put the two drainage tubes through the sides. Install a sump pump and a discharge pipe to the exterior. Once you're satisfied that the system is functioning properly, install clear plastic so you can monitor the situation over time.
Ron

Ron, thanks for the help. I'm just going to stick my responses in to your quote in red so that I won't miss addressing anything.

Getting a little far ahead here, since I definitely have had water pour in the vents. What's your suggestion if it is initiating in the crawl space and from outside? Again, wells would just fill with water if I had them, and they would require altering the concrete skirts, the walkways, and even the front porch slab which supports a post that in turn supports the roof of the house. Can o' worms. Big one.

Ideally you need to stop the water from "pouring" in the vents. If it was mine, I'd install the window wells and redo the walkway. But if for some reason you let it continue the drainage pipe and sump system would remove it from the crawlspace. Where the water would be pumped to is a solution for an onsite inspection as to the lay of the land and the amount of water being disposed of.
A generic solution would be a drywell placed away from the house.
Ron

Thanks, Ron. I will investigate having the wells added, but I'm not sure how it could be done without them just filling full of water since they are at the bottom of a hill. I can see that maybe we could have steel grates made up that fit over the wells so that the walkway might still be functional, but I can't imagine the drain system that would be required to keep the wells dry.

I'll try to get a few professionals out to take a look at the problem for me. You've given me plenty of information to consider.

A picture of the house on the up hill side would help, sounds like you need a perimeter drain line in front of the sidewalk. I hope the septic is on the down-hill side..........

Gary