0

My house is about a hundred years old. I replaced the roof and gutters about eight months ago.

When it rains very heavily, we get some water in the basement, in three tiny streams from three of the corners to the central drain. I have had several contractors over to make recommendations and have come to realize, they are (obviously) sales people interested (of course) in selling their own product. I have no idea what to believe concerning what is actually needed and actually best given what I'm seeing.

All these contractors recommended internal drainage, because that's what they sell. I'm reading in some places online that I should first make sure the grading on my yard is good, as well as the length of the drain pipes on my roof gutter system.

Lengthening drain pipes was easy of course. I'm now looking at the slope on my yard.

In general, over the yard as a whole, the grading is good--in general, everything slopes away from the house. BUT in many places right up against the house, there is basically a downslope towards the house. As in, just a foot or so right next to the house has, not as deep as a "trench", but just a slight downward slope toward the house.

So what I'd love to hear, is that can just dig up the plantlife (grass etc) right there at the wall, and get clay soil and basically pour a small layer of it all around the house, pack that in, then replant over it. Basically "patching" the grade so to speak.

Is it plausible that this would actually have a net positive effect on how much water gets down into the soil around the foundation, large enough to make the procedure worth it?

On one side of my house I just have like four feet of yard before it hits a fence dividing my yard from my neighbor's yard. That side of the house also is where the worst basement moisture problems happen. It also is a bit of a jungle so needs considerable clearing before I can be sure what the soil grade is like over there. But I am assuming that once I clear it, if it needs regrading whether as I've described above or more majorly, it will not be cool to just have all the water flow into my neighbor's yard. What do people do in cases like this? Is it plausibly DIY for someone who hasn't really done anything like this before? Or do I need to hire somebody? If the latter, how do I know whether they're doing what's actually needed and best and not just trying to sell me whatever it is they typically try to sell people?

I don't believe I'll be able to actually waterproof the foundation externally as I'm not convinced it's safe to do that kind of large scale soil shifting given the age of the home and the fact that the foundation does already have horizontal cracking and slight bowing on the three walls where moisture does get in.

Similarly, if I'm understanding right, any substantial external drainage system would involve something similarly invasive happening so I'm not so sure whether it's a good idea.

But all thoughts about this are welcome.

Including some pictures from all around the house below.

On this side of the house, it's just a few feet to a gravel driveway. Problem?

This is the four foot wide strip of jungle I mentioned. How to make the water not just go to neighbor's yard?

In terms of basement moisture, this is the second worst spot where it develops. But I don't know what to do about this random concrete block right against the wall of the house. Does it need to be removed or can I kind of get a seal onto where it touches the house or something?

Front and back of house look roughly like this, seems like an easier case, but am I right that I can just pack some clay soil down against the house to make sure the negative-grade bits abutting the house are positive grade?

5
  • I can see your soil doesn't drain well in the fence-having pic. I had poor drainage in some sections of my lawn. I was going to at least core-aerate, and a contractor even recommended a drainage system for $$$. Then after watching a seemingly too-good-to-be-true video about lawn care, I fixed it using, of all things, $1 baby shampoo. I used about a cup to treat a flood zone that was about 8'X12'. It did flood most of the time it rained, but has not flooded since, even in very heavy rain events. Use low-sodium shampoo. I can't see how $1 isn't worth a shot for drying out your side yard...
    – dandavis
    Jun 27 at 21:17
  • From what I'm reading, what baby shampoo does is make it easier for water to penetrate soil. That would seem to be exactly the opposite of what I'm needing--I need water to not get into the soil around my house, and instead to flow away from my house. Jun 27 at 22:53
  • you have standing water on that ground. That means any new water will go sideways (both toward and away from your house) instead of down. If that soil drained well, it could absorb said new water and more quickly sink it safely below your horizonal buckle. I wouldn't use it right next to the house, but about halfway to the fence and beyond. That way that plain saturated soil by the house can drain into the soapy side instead of your basement. I would also add/mix river/pond mud or kitty litter around the house to build up an impermeable slope.
    – dandavis
    Jun 28 at 6:09
  • Something I've been wondering is whether I can just go ahead and pour that extra clay soil/pond mud/whatever just, right over the grass, or whether I need to dig up the grass first. Please say the former lol Jun 30 at 16:12
  • The kitty litter is best mixed in, but will work (adding clay) eventually when added on top by seeping down. If you approach it with a "lawn leveling" strategy you can add either on top, but it will take a lot longer as you can only add about 1/4" a month or so. You could also rent a power sod cutter which will slice strips about 4" tall and a 18" wide from the turf. Then you can dump amendments in bulk and throw your "sod" back on top, though you'd want to do that in mid-late september to keep the grass from roasting with shortened roots and summer heat stress.
    – dandavis
    Jun 30 at 17:12
3

Instead of inviting salesmen, get a structural engineer or architect with the experience and work out what needs doing.

Look at the slopes and also if there are underground springs, poor drainage or just a high water level to deal with.

3
  • Last time I bought a house I tried a couple and they both implied I was weird for calling them to take a look at a single old house for anything less than a complete renovation. I guess I just ran into the wrong structural engineers?! Is there anything other than "structural engineer" I should try entering into google to make sure I'm actually getting to the people who will talk to me about something like this? Jun 27 at 18:45
  • 1
    @user3752935 surveyor comes to mind - knew one who would do similar stuff as he was a quantity surveyor but ask around locally - someone knows.
    – Solar Mike
    Jun 27 at 18:51
  • 1
    Your best bet is probably a "landscape architect," a specialist in planning outdoor spaces. The analogous engineering discipline is "civil engineer," not structural. Jun 29 at 18:02
0

I would not particularly seek out clay, but yes, you can fill next to the house, which often settles because it was dug up to put the foundation in, and filled, and then settled over a winter or two (or 102, but mostly the first one or two) and was not re-filled to maintain the grade.

Limit the extent to which you dig out, unless you are willing to come back in another year and re-fill on top after what you dug up re-settles. It's very difficult to mechanically compact to the extent that going through a couple of freeze-thaw cycles will, so it's generally easier to just let winter work for you, if you can allow it the time.

If you do dig out much, you can set an impervious later (such as XPS foam) at an angle away from the house underground, before filling on top, as an "underground roof" to move percolating water away from the house. But that's going beyond the basics of just making sure the surface grade is correct.

All you need to set surface grades away from the house is a straight board, a 4-foot level, and a 1/2" block for one end (the one away from the house) of the level. On the side with the short distance to the neighbor, slope out and then front or back (or both) depending where your water is to end up.

3
  • See also: diy.stackexchange.com/a/52671/18078
    – Ecnerwal
    Jun 29 at 19:16
  • I have actually been hoping it was possible, for something very basic, to do no digging at all. Will it be okay to just pour the new soil right over the grass up against the house? I figure that grass dies fast and turns into, basically, more dirt, in fairly short order, right? Jun 30 at 16:15
  • Also, I'd seen recommendations that I should use "clay soil" due to it being less water permeable. What kind of soil do you think I should use? Jun 30 at 16:16
0

Moisture is either coming up from below (a rising water table) or its coming from the surrounding ground water in the saturated soil, or both.

If it comes up from a rising water table, it will enter the living space from below through the crack between the foundation wall and slab.

If it comes from the surrounding ground water, it COULD enter the living space through the wall, especially if the EXTERIOR side of the foundation wall is not sealed properly.

Either way the moisture enters the living space it will need to be collected and disposed. I think the best way to collect it is on the exterior side of the foundation wall in drainrock and a perf pipe laid 6”-8” below the interior basement slab.

To keep the subsurface water from seeping through the wall, I recommend installing a moisture barrier on the exterior side of the foundation wall and install a 2” thick plastic mesh on the wall to allow water to flow down to the perf pipe. (If dirt is allowed to be backfilled against the wall, the dirt could hold the moisture giving it a chance to seep through the wall.)

Once collected it needs to be disposed by extending a solid pipe over an embankment or in a collection well and pumped away.

This may be the most expensive method of solving the problem, but it’s sure to work.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.