Wet basement help

[McKinley]

Hi,

My Basement gets wet after large rains and snow melts. It is a 90 yr old house with a concrete block foundation. I do also see efflorescence in some spots as well. Generally from what I can tell the water is getting through at the joint between the wall and the floor and around some blocks in some places. What would be our best option to fix this? Right now I am weighing two options, digging a trench and sealing the interior.

My problem with Digging a trench is that I only have about 5 feet between my house any my neighbor's property (city block). Also, I have some large trees near where I would want to dig and I am concerned about the roots getting in the way. On the other hand I heard that concrete sealant (like Radonseal) is not the best option as the water will still get into the brick. Thanks for your help.

 

[nealtw]

Your best bet is to dig down on the outside add a drain and waterproof the outside. The other option is really ugly, digging a trench on the inside thru the concrete floor adding a drain and install a dimpled plastic cover on the walls so water can run down to the drain behind the plastic. Yes then you have to repair the floor.

 

[McKinley]

So how deep would you suggest to dig if I was to dig and how far from the house? Water seems to leak from the bottom of the wall (and the floor through 1 crack in the foundation) so would sealing the exterior help still? How far down would I need to seal?

You did not mention sealing the interior, is that generally a bad idea?

 

[nealtw]

Sealing the inside I think would be close to impossible and concrete can absorb a lot of water and sooner or later it would be in the wall above the frost level adding pressure to the wall nothing good comes of that. The drain on the outside is placed just below the level of the floor inside and needs to drain away from the house or is pumped up and out.
The tree roots that you are afraid of are probably the problem if there is a drain there aready.
You can start by getting the roof water away from the house and make sure all ground is sloping away from the house and at least 8" of foundation is vissible above ground level. Sometimes these measures are all it takes.
If you do dig and drain the outside you want to plan on a good sealer for the walls and if the soil is clay type not sandy you may want to add that dimpled plastic to the wall, it holds the dirt and water away from the foundation.

 

[McKinley]

Hi Thanks for the info. I do have a foot and a half or so of foundation between the ground and my first floor. I think it looks like the best thing to do is to create a french drain system between my property and my neighbor's. I live on an block where the center houses on the block are the highest ground and each house next is tiered lower until they are street level on the ends of the block. I am one house from the end of the block so I assume that water is draining downhill from my neighbor's to mine.

So my plan is to dig and install a french drain system along the side of my house. I do have a couple questions:

How far from my house should this be installed?
How deep should I dig?
How far from the front and back of the house should I begin and end my drain system?

My plan would be to drain the water into a drywell in my back yard. I have attached some pictures to more clearly demonstrate my situation. Please let me know what you think.

Also, I have a crack in my basement floor that tends to leak. It looks like the prevous owner sealed it with some caulk-like substance, but the water is now leaking through. What do you suggest I reseal this with?

Lastly, in the concrete on the exterior. If I was to put sealant there, how for deep should I dig and seal? How do I clean the dirt off? There are a few cracks in the wall and also between the wall and stair, what type of sealant should I use for both cases? I have attached a few pictures.

Let me know if I am being unclear. Sorry about the large post. I just wanted to supply all questions at once as they could be interrelated. Thanks for your help!

 

[McKinley]

Heres a picture of the layout of the yard. the circles are the trees I was referring to and the red line is where I was thinking of installing the french drain

 

[nealtw]

To do it right you would remove the sidewalk and dig down to expose the whole side of the foundation. Short of doing that I would dig a few holes along side the house and in the yard where you a thinking of putting the drain see what the water is doing when it rains. Talk to others in your area about dry wells and how well they work. Does your area not have storm sewers you can tie to?

 

[McKinley]

Hi Neal,

That is a great idea. We have a rain coming tomorrow so I will dig some holes today so we can monitor the water.

I was not aware that it was possible to tie into the city lines. Is this commonly allowed?

I know you discourage the use of sealants on the interior walls. Just for curiosity, in what cases do you think it appropriate to use a sealant like Radon-seal V-Seal or other surface penetrating concrete sealants?

 

[nealtw]

We never see block wall foundations up here, but my fear would be the the blocks fill with water, that would attract tree roots, insects, and what happen to the wall if you get a deep frost on the same day the power goes out and there's no heat in the basement.
New houses in most areas here have a drain around the foundation at floor level like you need and another drain for the downspouts, both hooked up to the city storm and thats different than the sanitary system. You will have to check with the city.