gravity drain

[bhostasa]

Hi everyone. I would like to finish our basement and am having water issues. There is no sump pump or gravity drain that I have found so far. There are cracks in the slab of the floor and during really big rains, we get water up through those cracks.

I'd like to install a gravity drain under the corner of the slab and run it out the creek behind our house. I'm concerned about digging under the footer to run the start of the drainage tile. Is there a possbility that the footer could settle and damage the foundation? Our basement is made of poured walls, would it be better to bore a hole through the footer rather than dig underneath it?

Also, assuming I can get this gravity drain in, I'd like to fill the cracks and add a sealer to the floor. Does anyone have any suggestions on any of these kinds of products?

Thanks in advance for the advice.

 

[WayneB]

Just wondering how the drainage is around the outside of the house? Are you directing the rainwater off from the eves away from the side of the house foundation?

Is the only place you are seeing water entering the cellar is the floor? What is the water table in your area?

As for patching the slab and sealing out the water, that can be done, but there are reasons for the cracks and I would think it is stress and the cracks may redevelop and you will have the same water problem, but maybe in a different area.

Getting the water away from the foundation would be a good starting point. I think you might want to check with a professional to see what they might suggest you do. You might be able to add a french drain to move the standing water away from the foundation this would require digging down beside the foundation adding the drains and then adding crushed rock that would permit the water to enter the drain and be directed away from the house.

Cutting in a drain gutter around the inside of the foundation to direct water away from the floor will aid in moving the water out of the cellar, but it might be best to eliminate the water totally if you plan on refinishing the basement.

 

[CurlyDave]

When I was considering boring through a poured concrete wall, I found that the cost of boring a hole was much, much higher than that of making a straight saw cut.

In order of cost and difficulty:

First, I would take WayneB's advice a little further and be certain that my gutters drained into the creek.

Then I would consider cutting out a square of concrete in the slab, making a sump, and running the discharge of a sump pump up and over the concrete wall, and out to the creek. Plan ahead on the location so that it can be hidden if you ever want to finish the basement.

If that fails, do the french drain, again running a drain to the creek. Possibly this would be the time to consider horizontally drilling for a drain under the footer for the wall. This would be the option least likely to crack the footer or the poured wall.

You need a trench for the horizontal drilling and the same trench could be used to burry the drain to the creek.

 

[bhostasa]

The house is a ranch with a walk out basement. The drainage is good at ground level. The area that I considering running the gravity drain is the walk out.

My idea is to tie both downspouts that are on either end of the basement into the gravity drain. I would have to think this would be plenty of drainage and lower the water table (which typically isn't high at all).

CurlyDave, I was planning on cutting the hole with my saw like you said. Do you think that would be the preferred method instead of digging below the footer?

 

[JB4310]

You could cut thru the footing in you had to, just not at the walkout where there is no foundation above IMO.

But going under the footing would be the easiest, it's not gonna hurt anything, and if you do it at the walk out it would be the least amount of digging. you don't want a dip or trap so from there out the pipe should lay evenly with a little pitch to the exit point at daylight. depending on the topography you might not have to go all the way to the creek, if the yard drops off lower than the basement floor 20 ft from the house then let it end there.

You only need 1-2% pitch outside, inside you should have a sub-floor footing pipe around the perimeter tied into that new pipe going out under the footing. the inside pipe should be top of pipe at top of footing, pitch is not necessary but you can build it in a little, as you get to the exit pipe to tee into you would be at the bottom of the footing. you would want an access cover at the tee or small sump for monitoring and cleaning if needed, so I'd dig just to one side of the walk out so the access wouldn't be in the traffic path.

Installing the inside footing drain is gonna be a big job, but is necessary for a dry basement especially if you're investing in finishing it. Once you have the interior footing drain system properly installed you don't have to worry about the cracks and joints,
without the footing drain nothing you do to the cracks and joints will stop the water.

It's a common misconception to think the water table is rising causing the leaks in a basement, it's the storm water that's trapped and slowly leaching downwards that puts hydrostatic pressure on the foundation. The slower it percs the worse the problem, if your home was on sand or gravel you wouldn't get water in your basement.

Good luck, JB.

 

[buckeyefarmer]

But going under the footing would be the easiest, it's not gonna hurt anything, and if you do it at the walk out it would be the least amount of digging. you don't want a dip or trap so from there out the pipe should lay evenly with a little pitch to the exit point at daylight. depending on the topography you might not have to go all the way to the creek, if the yard drops off lower than the basement floor 20 ft from the house then let it end there.
.

If you have a walkout, there should be a frost footer there, meaning the footer is a lot deeper than the rest of the house.

 

[Kays Supply]

DON"T connect the down spouts and drain together. I have seen water shooting a foot high out of basement floor drains when the common drain was clogged. You can use the same ditch, but run separate pipes.

 

[JB4310]

If you have a walkout, there should be a frost footer there, meaning the footer is a lot deeper than the rest of the house.

Very good point, and his may be like that, depends on if the whole back of the house is at that walk out level or if the walk out is in a cut section of the yard with retaining walls on both sides. The majority of the ones I see are with the retaining walls and have the footing right below the floor, on those there is a a 3-4 ft foundation wall across the back and wood framed from there up. The ones where the yard is lower than the floor across the entire rear are framed right down to floor level and would have a footing down to the frost line.

If his does have the lower footing he is gonna have to go thru the foundation wall, It's all grunt work but can be done. probably best right at the doorway, cut down thru floor and chip away at top of foundation, he mentioned using saw but we only use jackhammers in that situation.

DON"T connect the down spouts and drain together. I have seen water shooting a foot high out of basement floor drains when the common drain was clogged. You can use the same ditch, but run separate pipes.

Yes another good point, don't connect the 2 together, keep that footing line dedicated to the one job. burying leader pipe discharge is only necessary if there is a ponding water problem, if the water runs off away from the foundation then it's not needed to put them underground.


JB.

 

[bhostasa]

Our place has the walk out level across the entire side of the house not just at one entry.

Good idea on the two lines in one ditch. I was planning on using a check valve to help with any clogs of slow drainage but two lines seems to make more sense.

Do you think it's possible to do all of this without a sump basin cut into the floor? Could I do everything under the slab without cutting a hole? Since it's very seldom that we have any water issues, i was thinking about using a 9 x 9 catch basin (or something similar) under the slab.

 

[JB4310]

You have to open up the floor just to see what you have under there. Pretty easy to go thru the floor, usually 2-4 inches thick.

Sounds like you're not keen on installing a complete footing drain under the floor, and there's a small possibility you might get away with out doing it, but you will need to open the floor at least where you're bringing the pipe in to see what's going on and install a small access basin.

IF you have all uniform crushed stone like 3/4" or 1 " under the floor then you may get away with just having a perforated basin and that exit drain. Another small possibility, you may even have a footing drain under the floor already, or may find an exterior footing drain when you start digging on the outside. depending how they do things out there and how old the house is.

If you have anything less than a good uniform crushed stone under there then probably wont drain the whole basement from that one point. and because your bringing the pipe in on the side that has the lowest grade around the house, that's the side that needs the least relief. the side that has the grade highest over the floor is where the hydrostatic pressure would typically be greater.

Unfortunately there is no substitute for a properly installed perimeter footing drain system, either inside or out. Around me everything is done on the inside and IMO that's the best way, but there are those that believe as strongly that outside is the better way.

JB.