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

[Investorguy]

Sounds good. I'll look into that. I imagine they'll have means to pump/auger it through the vents.

I imagine I won't start on this project until it dries, which is probably in May at the earliest. That way I can more easily lift up the vapor barrier and keep everything neat.

Given that I've got a lot of room to move around down there, I don't expect it to take much more than a day or two. If they can pump it in w/ a hose, it'll take a few hours. I'll gladly pay that bill if it's possible.

Does anyone know if they can pump/auger small washed stone through a pipe?

 

[CurlyDave]

Does anyone know if they can pump/auger small washed stone through a pipe?

I don't know about pumping/augering stone, but you are going to need enough of it so that it is going to be worth building a chute from 2x6s and plywood if it can't be augered in.

If you can find a small wheelbarrow which can fit through the opening into the crawlspace, that would make spreading it a lot easier. Even if you have to disassemble the wheelbarrow and re-assemble it in the crawlspace...

Get the wheelbarrow under the chute opening and fill 'er up. Stop adding gravel until the wheelbarow is back in position.

The crawlspace looks very good, except for the water. I still think you need an engineer to look at it and make certain there wasn't a construction mistake somewhere -- water in a crawl space is not normal.

If this was my job, I would put a big fan over the hatch pointing down to blow air down there while the work was going on. I would also consider paying day laborers to spread the gravel. No matter how nice that crawlspace looks now, a few hours of spreading rock in there and you will be wishing for an easier way.

 

[Investorguy]

A chute is definitely in order if I have to have a pile of it delivered. I'd want to construct something I can dump a loader full of gravel into (albeit slowly).

I'll definitely be calling an engineer too.

 

[EddieWalker]

Investorguy,

As a general rule, I try to avoid engeneers, archetects and degreed profesionals as much as possible.

Before I start covering up the problem with a couple thousand dollars worth of rock, you better check with a so called expert.

Your problem is standing water in your crawl space. The majority of the advice seems to be leaning towards covering up the water with gravel.

What will this solve???? Will the water still be there?

All your doing is hiding the problem with gravel.

As for mold, it's a secondary concern here. If you have standing water in your crawlspace, the integrity of your foundation will decreese over time. If you hide the water with gravel, than you won't even know what's going on down there.

Address the problem.

Why is water coming into your crawlspace????

Can you stop it from getting in there?? My earlier post about trenching isn't practical after seeing your pictures. It would need to be many feet deep and really would look like a mote.

A very large french drain dug around the perimiter and drained to a lower area will do wonders do dry out your foundation.

Last case scenerio would be to let the water come in, but find a way to get rid of it as fast as possible. Sump pumps are designed for this. I've never put one in, but from what I've read, they seem very straight forward.

Another option might be to dig a drain from the bottom of your crawlspace, under or even through your footings and pipe it all the way to a place it will discharge.

Good luck and don't do anything rash. It's real easy to go for the quick fix and hope for the best without regard of how much worse it will be down the road.

Eddie

 

[Investorguy]

I agree Eddie. I don't want to throw a bandage on a broken arm. I hope the professional will be able to shed some light on possible solutions.

What I expect he'll say, however, is that the crawl was simply dug too deep and needs to be filled in. Trying to drain it seems like it would be like trying to drain the beach at the water level... you can dig and did, but that's just where the water is. I say this b/c the footing drains are draining out at the ditch along the road 24-7, whether it's rainy or sunny. It stops draining some time in May, when the crawl dries out.

At least I think those are the footing drains.

 

[Highbeam]

"Address the problem.

Why is water coming into your crawlspace????"

Eddie, it's groundwater coming up from below. If he went outside and dug a deep hole it would fill in with ground water to a certain depth consistent with the water table, putting the dirt back in that water logged hole doesn't get rid of the water. We're not talking about surface runoff here.

The constantly running footing drain is maintaining an artificially low groundwater level around the footing but the footing drain is probably setting on top of the footing so the water table is above the surface of the crawlspace floor. If he dug the crawlspace 3 feet deeper and left the footing drain where it was, the crawlspace would have 3 feet of water.

Hiding the problem isn't what is going on, he is raising the finished grade above the water table so as to support walking and the vapor barrier above the saturated subgrade. The water will still be there below grade. Lowering the water table below the base of the footing with a deep footing drain would drain the soils below the footing subgrade and could cause them to shrink as mentioned in a previous post. The sand isn't to displace water, the water will still be there at the level of the footing drain, it is to raise the finished grade above the water table.

If you sump pumped it long term, you could expect your footing drain to stop flowing because your water table will now be lowered below the footing drain level. Check the soils maps for shrink/swell potential of your particular soil. Clays shrink a good bit when they dry.

I thought about sand since it can be blown. I've blown sand into casings around water lines. Plus it'll be nice to the vapor barrier and if the sand is a uniform sized grain will have just as much void space as gravel. It is more likely to displace under your feet though. Remember the point isn't to allow free movement of water or to seal the ground, it is just to support your weight and the vapor barrier above the water. Crushed rock would be ideal for the minimum thickness giving the most firm base.

 

[EddieWalker]

Highbeam,

I agree with you one hundred percent that his issues are coming from the water table. But he also said it's not a daily problem, but something that comes and goes. Heavy rains raise the water table and increase hydralic preasure forcing it out through the point of least resistance.

There is a good chance that this is what's happening. We're just guessing, but if this is the case, than the water is still going to do this. Adding rock wont solve anything. Sand is better, but it will still be just a cover.

Since it's not a static level, but a variable one, this means the water table is below his footings. Draining it out will allow it to dry faster and cut down on soil saturation. When it rains, the water table rises and he has standing water. After things dry out, the water prolem is gone.

Your example of digging a hole and seeing where it fills is a good example of where the water table is at that time. He already has a very large hole in the ground, and it's dry most of the time.

What has me really curious is why would a builder go to all the additional expense in time, effort and material to build such a deep footing? How many more hours on a tractor do dig these footings and walls? How much more time in labor and materails to frame up the walls? Rebar, concrete and labor add up. Just guessing, but his foundation could easily cost 4 times as much to have built as a standard one.

Do homes require permits there? Was there a blueprint or soil study done? Some places in California require the footings to go down over 20 feet. Who signed off on the permits?

THERE IS A REASON for his footing being so deep. No builder with half a brain is gonna triple the amount of concrete he wants to put in the ground just to pay his crews extra money. The only way this makes sencse is the builder knows something we don't. Investorguy needs to find out what the builder knows and why it was built that way.

If you can't find the builder, find the inspector. Somebody made the builder do it this way, and somebody inspected it and signed off on it. Is there a local cement company? Start asking around when you see a crew pouring concrete. I bet this foundation is different enough that people will remember doing it.

Putting fill in there, either sand, rock or dirt, will aslo act as a sponge to some degree and keep moisture there allot longer. This will increase the saturation of the soil that the house sits on. This is bad. I think ther's a reason this wasn't done when the house was built. I do not think it was a mistake or an oversight. They dug the dirt out for a reason. It was sitting right there. If they wanted it back in there, they could have done that allot cheaper than hauling it off.

Another point to consider is why didnt' the builder just dig down the depth he had to go and pour the footings there. WHY DIG DOWN THE ENTIRE CRAWLSPACE?????

Idealy, I think he needs a perimiter drain to keep runnoff away from the house, and a drain in the bottom of the crawlspace to get the moisture out as imediately.

Eddie

 

[Highbeam]

"What has me really curious is why would a builder go to all the additional expense in time, effort and material to build such a deep footing?"

Good question, this foundation was extra expensive. When spec'ing out my house I had to pay several thousand for each additional foot of height above the code required 2 feet of crawlspace. I suspect that the depth was required to get to the good dirt with a high enough bearing capacity to support the home. Maybe a layer of firm soil underneath muck topsoil like what he sunk his tractor in. Then he may have had a floodplain requirement. We need to place our finished floors at the 100 year flood plain or higher in the state. The tall stem wall is not common. We don't have a frost line here.

For whatever reason, houses are built on holes here. We don't trench down for foundations. We do a digout for the whole crawlspace and sometimes trench below that for the footing istself. Every crawlspace I've been in is dug out this way. The big ol' hole is dug and the material moved outside of the hole. Then the concrete poured and then the digout material use to backfill the foundation by pushing from the outside. The only way to get it inside the foundation is to scoop it in and spread it out by hand and that takes extra labor. The extra labor wasn't spent here, plus the tradesmen prefer a deep crawl.

I see the problem as surfacing groundwater in the crawl. Raising the grade above the maximum water surface level would eliminate the problem. Raising it even higher would leave a thickness of material that should always be above the water table and not saturated except by wicking. Vapor barrier on top of that and this problem is history.

A drain (ideal) or sump pump in the bottom of the crawl is a great idea.

 

[Paddy]

InvesterGuy,

Two points;

I still have not seen any reply with regards to elevation. Do you have any area on your property that is below the footer?? You can use a lazer level and go in steps of the limit of the level. Or, setup a step ladder in an area you suspect is lowest. Place a 4' level near the top step catching the paint tray devise. Point this back at the house. Level the level. Now look down the top of the level like a gun site. Note the point where it intersecs the house/grade near the house. Compare the distance at the step ladder to the distance at the house.

Second, with your foundation having that wood wall sitting on the footer?? I don't see how you could fill any. You are with in inches of wood and dirt/water. Descride that wood wall, what's going on on the other side of it? because it either above grade or below.

Answer these two questions and your solution will come alot quicker.

 

[CurlyDave]

Paddy has a good point.

The wood cripple wall does sit on a PT sill, but in most areas there is a code about how far the footing must stand proud of the dirt. This is to prevent termite infestation. Even if there isn't a code, you still want this distance above the dirt or the proposed gravel fill in order to keep the termites out.

Same thing with the wood brace for the beam I see scabbed onto the stem wall. The bottom of this must be the correct distance above the dirt or the fill, if that is the solution.

See what the engineer says...