Water in my crawl space: how best to drain it?

[SnoFalls]

</font><font color="blue" class="small">( Of course the above is done after It has been verified that the surface grading outside the home isn't sending runoff towards the foundation and that the downspouts are tightlined to the ditch. )</font>

FIRST ensure about that ... my guess (from the pics) is that one side might be feeding the crawl hole from the surface and/or the downspowts are doing it. I honestly think you're more than 3' above water table (which you can test by digging a hole BTW).

That ditch by the road is lower than the crawlspace correct? Is it holding water or is it running off (year round?, or just now?)

I think your foundation drains are faulty ... did you build or buy? If built, any recourse to the builder for the screwup?

Water will take the least course of resistance, so if that slight "upslope" encounters a properly functioning and located drain, it'll flow that way to the ditch, same thing with the downspouts. Otherwise it'll find that crawl space, since that's the "easy" place to make a pool.

 

[Marlowe]

It sure looks to me that the problem can be fixed. The land is fairly flat though and my thoughts are that there will be plenty of humidity during the wet season for mold to grow anyway. Mold doesn't need standing water, just moisture. I'm certainly no expert, but I am experienced with standing water in a crawlspace. I had that problem for years in my current house. I tried several sulutions such as gutters with drains to the road and such. I even plumbed the drains on the A/C units to an area far removed from the perimeter of the house. Still had standing water, until I found a broken drain line coming from the washing machine. It literally dumped all the washwater under my house. Simple fix that took me way to long to find the problem. Oh well, the good news is that I can't find any mold on the wood under my house even after years of moisture exposure.

The bad news is that once I cured the problem and dried up the water for good, my ground dried out too much allowing the clay soil to shrink. Shrinkage allowed my foundation to settle and crack. Major bummer, and a real pain to fix.

I'm building my new house now, but with all that experience behind me my new neighbors look at me funny and ask a lot of questions about why I'm paying so much attention to the foundation. I want to leave all those nightmares in the past.

Good luck on getting things dried out.

Tom

 

[RFB]

Be sure to use a GFCI for temporary or permanent pumps.

 

[Investorguy]

Okay here are some more pics. First, a couple more of the house and the slope you can see.

(for larger pics, go here)

on that last one, note the position of the foundation vents.

Now, the crawl space pics; keep in mind where the vents hit above ground.

See what I mean? The crawl was dug way deep. A little too deep.

That's ~ half my house. About that same amount of space on the other side of the wall cooridor in the middle.

And here's what it looks like going down there. You get in through a trap door under the stairs. You can see how far I have to extend the telescoping ladder to hit the bottom.

Those images help anyone? Sorry in advance for dial-up users; I know it may take some time to load those up.

 

[B8FISH]

Iguy--on the first pic of the crawl space, it looks like you see where there is moisture on the wall, or at least a moist wall--is this true? It looks like the end that has two vents showing is damp, then runs down diagonally towards where you took the picture. If this is the case, let us know. I would guess that end is where the water is making its entry?

 

[Highbeam]

That's a great crawlspace, no pipes or junk hanging down too far. You would have plenty of room to retro in more insulation or even radiant underfloor hydronic heat. You could even mount your air compressor down there if you had a way to get it in.

Anyway, it looks like the lowest visible joint in the wall is where the footing meets the stem wall. There should actually be a step there since the footing ought to be a good bit wider than the stem wall. It sure appears that the builder didn't backfill inside the footing at all. Dug a big flat bottomedhole, built a foundation, and then used his machine to push material from the digout up against the outside. If he set your footing drain on top of the footing, like most folks do, then your problem is simply lack of fill in the crawl. You could put any fill material in there and the water won't come up any higher than it is. Sand, stone, native, whatever could be pumped in using a concrete pump. I expected it to look much worse.

The other nice thing about filling inside your crawl in this situation is that your stem walls are now acting as 5 foot tall retaining walls holding back the material outside of your home. By filling the inside, the forces cancel each other and there is less side load on the foundation.

Even if you simply fill your way out of a wet hole, it wouldn't hurt a darn thing to have a sump pump on duty down there. It uses no power to just sit there inactive.

There was a previous post about mold only needing 50% humidity. Well, here in western washington the only time it is less than 50% anywhere is when we are in one of our one week cold snaps or in the hottest part of the summer. The rest of the time it rains and I see the gauge resting at 98% RH. We can't worry about humidity, but we can all assume that standing water is bad.

Now go put that brush hog in the shipping container so it doesn't get rusty.

 

[Investorguy]

So filling in w/ sand would work out, even absent any outside trenching?

Should sand or 5/8ths or pea gravel be used? Is there any reason to choose one over the others?

Anyone else have an opinion on just filling in a few inches of sand... basically up to the stem wall, as the water only goes up about that far.

 

[Investorguy]

</font><font color="blue" class="small">( Iguy--on the first pic of the crawl space, it looks like you see where there is moisture on the wall, or at least a moist wall--is this true? It looks like the end that has two vents showing is damp, then runs down diagonally towards where you took the picture. If this is the case, let us know. I would guess that end is where the water is making its entry? )</font>

I think that may be a shadow from the flash, but I'm not sure. It didn't seem damp anywhere on the walls when I was down there.

 

[jeffinsgf]

I would fill with pea gravel up to the top of the footing and see what happens. I think that would solve your problem, and it certainly won't hurt anything. As mentioned, digging in, lining and wiring in a sump pump would be some pretty inexpensive insurance against that 100th year wet season.

 

[dmccarty]

Investorguy,

Find out who you closest supplier/quarry is located. That might help determine what to use as fill. I would prefer a smal washed stone. In NC I would use a 78M. Its washed so there are no fines, you can kneel on the stuff without much if any pain, and it would be easy to move in a confined space. The largest 78M would be about 1/4 inch around. I have been using some 67 stone which is washed but its about an inch or so long. I can rake it or shovel it but the smaller stones are easier. And the larger stones will dig into your knees and are more apt to rip/puncture the vapor barrior.

The 78M stone should be easier to get into the crawl space as well. I think I would stay away from sand since I would think it would hold moisture longer than a stone but that just maybe wishful thinking on my part. Wet sand is about 4,000 pounds per yard as well.

The quarry can tell you how much the stone will cost per ton. In my area a yard of ABC, road base, is about 4,000 pounds and is 8.25 per ton. I can get a truck to haul 15 tons for $65/hour or a 20 ton truck for $75/hour. I'm pretty sure the washed stone costs more but I have not check the prices in awhile.

Hopefully you can take the foundation vents out and pour the material into the space. Its going to be some work moving that stuff in the crawl space.

Later,
Dan