Thread: Drainage Problem

Hi all,

I have a drainage issue with my townhouse and I am in a dire need of a solution. There is an area in between my home and the next home that is pretty flat, about 30 feet long and 11 feet wide in between the houses. During the rains, most of the water pools next to my wall, so there is a slight slope towards my house. I attached pictures of the area from multiple angles.

IMG_1960.JPGIMG_1961.JPGIMG_1963.JPGIMG_1955.JPGIMG_1956.JPG

Somebody suggested a french drain dug 12 inches wide and 12 inches deep and only 12 inches from the foundation of the home, which would also be re-graded towards the french drain.

My concern is that 12 inches is too close from the house and that there is not enough slope in the area (which is pretty flat) to drain it to daylight...

Any suggestions or alternative solutions will be greatly appreciated.

Thanks again!

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Get a load of soil (or as many as needed). Spread it along the wall to raise the grade at least 2 courses of brick up and grade it to the mid point of the two buildings. Your neighbor should do the same thing.

Originally Posted by Steve Payson

Get a load of soil (or as many as needed). Spread it along the wall to raise the grade at least 2 courses of brick up and grade it to the mid point of the two buildings. Your neighbor should do the same thing.

That could cause additional problems if the structure is not constructed to allow for such.

What may turn out to be the only practical solution (short of sumps and sump pumps, etc) is to dig a full length dry well (kind of like a french drain except that it does not go anywhere).

Dig down about 6" or so next to the building, then slope down to 12"-18" out between the two buildings (presuming, naturally, that your property goes to the center between the two buildings), and at the center make the dry well 18" wide - do this for the entire length of the area.

Then fill the trench with gravel to within about 2" of the top (this will allow you to lay sod over it, and sod is typically about 2" thick - not counting the grass). Then lay a layer of filter fabric over the gravel, this will keep (slow down the process of) dirt from filtering down into the gravel and filling the air spaces.

Now lay sod on top.

You now have a long dry well which should (depending on the soil under and around the gravel) do a lot to allow the water to percolate down into the soil faster, it might not keep up with a heavy downpour, but it might allow it to drain down below sod level within an hour or so.

If the soil is clay or clayey ... well, there will not be any percolation ... which would mean drainage to daylight or sump pumps.

I agree with Jerry's comments. I would also be concerned about the topsoil areas covering the face brick. This is not the best construction detail.

At face value it is typical to at least see a slight bit of the top of the foundation wall just above the grade line.

Is this a freehold townhouse where owners own the land and fixtures and responsible for upkeep? If so great but if not you may own a town home (condo) where the common elements are not owned by you, you would have to seek direction from management to alleviate the pooling.

Secondly before you start digging trenches I would have a utility locate company come out and make sure there are not any telephone, cable, et ceteras buried where you want to dig.

Originally Posted by Raymond Wand

Is this a freehold townhouse where owners own the land and fixtures and responsible for upkeep? If so great but if not you may own a town home (condo) where the common elements are not owned by you, you would have to seek direction from management to alleviate the pooling.

Here in the states (South of the Border, so to speak), a townhouse and a condo are distinctly different as a townhouse is basically owned from the ground below to the sky above, whereas a condo is basically owned 'paint to paint' inside the unit and there is no ownership of any part of the structure, or even common walls (shafts) within the unit, the only ownership of the structure comes as being a member of the condo association, which owns the structure and all common areas.

Secondly before you start digging trenches I would have a utility locate company come out and make sure there are not any telephone, cable, et ceteras buried where you want to dig.

Absolutely.

Also needs to verify how far out from the structure he owns before digging, as he may own to the center between the buildings, to 10 feet out from his building, 5 feet out, or maybe only under his building ... which is why is said "(presuming, naturally, that your property goes to the center between the two buildings)" in my previous post.

Thank you guys for your feedback. Yes, the property line is in between the houses and I will call the utility company to mark the underground lines before starting to dig.

Jerry, why do you think a dry well would be better then a french drain? I'm thinking that maybe there is a chance a french drain might drain to daylight, even if only around 9'' level difference between one end to the other? I'm still concerned that 6'' next to the building is too close and will create a moat putting even more pressure on the foundation?

Maybe a hybrid solution with grading towards a french drain or a dry well right in the middle (5' from the wall)? Or would that be too far?

Right in the middle between the two buildings is ideal, except that there is some underground utility there in your pics. I think your problem stems from too much fill between the buildings. On top of that, they graded it toward your place. There should to concrete foundation visible below the brick veneer. We say 6 to 8" but that may not be practical.
The soil should slope away to a swale, a wide open ditch, between the two buildings. Google it. Since it is clay, a swale might be best, and certainly less costly then below ground drainage. You will however, need to truck the excess clay soil away. A layer of sandy topsoil isn't necessary but will help the sod to grow and absorb some moisture.

Originally Posted by gchope2k6

Jerry, why do you think a dry well would be better then a french drain?

A french drain is typically designed to drain to one end or the other.

A dry well is intended to help percolate the water down into the soil where the dry well is.

I'm thinking that maybe there is a chance a french drain might drain to daylight, ...

If you think a drain of any type will drain to daylight, go for it. It doesn't look like you have enough slope to bury a drain and then slope it, and have it open to daylight.

I much prefer sloping the surface to drain as opposed to an underground drain. Underground drains tend to clog easily and become overwhelmed during heavy rains. Sloping the surface is with a drainage swale takes a bit more time and attention to detail than simply burying a pipe but is more effective in the long run in my opinion. Sandy soils or gravel can change my perspective but with typical tight topsoil in my neck of the woods, a surface drain is more effective in the long term.

Unless this is new construction, there is a possibility that drainage used to work and now it doesn't. I have had several swales fill in over the years, and have solved basement floods by regrading to original (usually by shovel).

In other words, try the simplest possible solution first.