Is sump pump possible?

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  #1  
Old 06-13-04, 03:26 PM
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Question Is sump pump possible?

A master bedroom was added to the front of my house (well before i purchased the house) resulting in a separate crawlspace. The lot slopes down to this crawlspace. It is adjacent to main crawlspace and has a connecting concrete wall between them, with a hole in the bottom of the wall. I noticed this week puddles of water in the newer crawlspace. Also a little water had seeped through the hole to the main crawlspace which otherwise was very dry. The main crawl space is easier to enter and has more height but the crawlspace of the addition is only 4ft high. The floor there also seemed, at least to me, rather uneven, resulting in a deep puddle here and a deep puddle there. Although the concrete around the floor of this crawlspace is wet, I didn't notice any other damage and no mildew or unpleasant smells. Obviously the problem needs to be fixed but i cannot afford to spend thousands of $ on it.

I hope the problem can be fixed by installing a sump pump in this added crawlspace. Given the tough working area, do you think that is possible? Would a submersible pump be better here or would a pedestal pump still be preferred? I didn't see any elec outlet nor any 'block" to put a drainpipe to the yard through. This project is more than I can undertake myself and I will look for a professional to do the work (drain specialist?). I hope this person will also be able to do all aspects of the installation, including electrical and drilling a hole in the wall for drainage. What I have described here, is this rather typical for a crawlspace or should I expect horrendous quotes for installation because of the crawlspace being so low, etc?

In addition, I will install a drain curtain myself at the outside perimeter of the house. The soil is heavy clay. Since water has already reached the crawlspace, do I really need to dig to the crawlspace footing, 4-4.5 ft deep? This would be impossible due to tree roots, etc. If i lay the drain curtain 1-2 ft below soil level, would this help the overall drainage or would i just be wasting a lot of time?

Any input greatly appreciated!
 
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Old 06-13-04, 04:18 PM
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asking,

If it were me, I would try to resolve any and all issues from the outside. Yes, trying to install a drain tile system within crawl space would be expensive to say the least. Low area makes it a time consuming and labor intensive job. Bear in mind I am talking thousdands.

As it seems many areas of the country have been receiving more than a fair share of reain, some issue which were never present before re becoming so now.

The best way of keeping water away from a foundation is to divert downspouts away from the house, and slope the ground away from the house. In that way any rain, snow melt, etc. will not drain down into the soil near the foundation. For any water that does drain down into the soil near the foundation, and also for any excessive ground water already in the soil from a high water table, a perimeter drain tile and stone or gravel backfill has been the standard approach. This is a waterproofing system. The same application is done to the "interior" of the lower level and this works extremely well especially in older homers when exterior applications cannot be done. In your case, since you ahve a crawl, I would suggest exterior methods of repair.

When water gets into such a gravel backfill, it quickly runs down into the drain tile and is diverted away through a pipe either by gravity or a sump pump. When a drain tile is used, but soil is used for backfill, the water can't drain away as quickly, so it tries to drain through the foundation wall. If enough water is present, hydrostatic pressure will force it through any opening it can find in the foundation wall, no matter how small.

The purpose of the stone or gravel backfill is to relieve the hydrostatic pressure. With the correct backfill material, the water will travel the path of least resistance: through the backfill into the drain tile, rather than through the foundation wall. I will point out that drain tile comes in two styles - rigid and flexible. The rigid has a slot on one side and this is installed with slot down. The flexible has slots on 4 or 6 sides, if you will but this should be installed with a silt sock over it. Costs more but prevents silt from getting into the pipe. Most homes, for interior applications use the flexible but either is acceptable.

When the soil is merely damp, as it often is, water isn't the problem. When damp soil is next to a foundation, it will cause the foundation to get damp. The dampness will work its way through the foundation wall and eventually enter the basement or crawl space. Concrete and masonry are actually very porous, so dampness can move through such materials fairly easily. (This is done through a process called capillary action.) Once the dampness reaches the interior surface, it can evaporate into the basement or crawl space, increasing the moisture in the air.

To stop the dampness is relatively easy because, by not being in form, there is no hydrostatic pressure. A simple foundation coating will do the job. This coating is called dampproofing. It isn't a substitute for waterproofing.

If you are seeking assistance on this, get a least 3 bids and compare apples to apples. Be prepared for some high costs.

Hope this helps!
 
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Old 06-13-04, 04:59 PM
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Question sump pump and exterior drain tile

Thanks, Doug, for your lengthy reply. I definitely will do the exterior perimeter drain. Could you tell me though whether it should suffice to put the pipe in about 1-2 ft below soil level ? Due to tree roots etc it will not be possible to dig all the way to or below the base of the crawl space.

I had not even contemplated doing a perimeter drain system within the crawl space. Should i not get a sump pump though to get the crawl space dry again and also as extra protection in case the exterior perimeter drain will not be enough???

The house has good downspouts and I clean the gutters several times a year. However, I live in an area with lots of rain, and I am worried about the slope of the lot from street to house and high water tables particularly in winter.

Thanks
 
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Old 06-13-04, 05:32 PM
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asking,

You're welcome!

What you suggest, may be ok but there must be some grading done to really avoid water coming down to the addition. If you think the 1 - 2 feet down would suffice and this is all that can be done, this may be feasible. I do not guarantee that the results will be fool-proof. I am not sure how deep your existing crawl space is under the addition but if the exterior grade is at or just above the inside grade, this may help.

By chance, are any tree roots causing the problem now occurring?

With what you mentioned about lots of rain, high water table, this all adds up to a problem that may require an investment which may be expensive. A good professional should assess what you have and then go from there.

Hope this helps!
 
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Old 06-13-04, 07:08 PM
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Question thanks once again

Doug, thanks once again and apologies for being so stubborn on this issue as i am still confused.

Below the master bedroom the crawl space is only four feet. I suspect it is only 4 ft because just a couple of feet in front were a couple of massive trees. These trees were becoming very dangerous and i had the trees removed. What is left are the stumps and the major roots. I did not see signs of roots inside the crawl space. When the trees were still there the soil remained a lot drier and the crawlspace had a little moisture on the floor but no puddles.

The lot slopes down from the street oh about 5 ft and there is a narrowish walking area between the garden and foundation. This walking area is level with foundation, about 3 ft higher than the floor of the crawl space. It is here i wanted to dig the perimeter drain and just going 1.5-2 ft is hard work since there is little room to manoeuver. I will be very careful to dig a good slope for the drain. Will use some 3/4" crushed rock, flexible perforated pipe, fiber fabric, more crushed rock and top off with topsoil.

Do you feel i should try this solution (i.e. exterior perimeter drain)first and let the crawl space dry this summer when we hopefully get some drier, warmer weather??? Or should i go ahead with the sump pump inside the crawl space as well???
 
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Old 06-13-04, 07:15 PM
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asking,

My rule of thumb is to avoid paying more than you have to. I would first attack any issues outside first and see what happens.

I am assuming that this crawl space has a concrete floor or is it dirt? Most are just dirt, so if not and you have concrete, and possibly using this for storage then depending on any exterior improvements, then tackle the inside.

Does this help?
 
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Old 06-13-04, 09:01 PM
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Smile Thanks again!

Yep, you sure have been helpful. I follow your advice and will tackle the outside first and then see what happens. The crawlspace floor isn't concrete; part of it is just dirt and then there are patches of crushed rock that almost seems solid. It is exactly that what makes the floor so uneven and that makes me wonder how readily ALL the water would flow to a sump pump if i installed one. Anyway, i will do the outside and let the floor of the crawl space dry out in the next few months and examine the situation more closely then.

Thanks again for your help!!!
 
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