I am working on a project to improve the drainage around my basement walls. The foundation is cracking and leaking after only 5 years. There is a footing drain in place that is working, but the soil is clay. Drainage is poor around the house and the roof is metal without gutters.
Based on all the information I have found my current plan is to excavate a trench around the basement, line it with road fabric and fill with gravel. This would improve the drainage and relieve some of the presure on the walls. I will then also slope the grade from the house and added shallow drainage trenches with gravel to pull the water further from the house.
Questions I have are is this a good strategy , what kind of issues with digging around the foundation do I need to be aware of ?
Thanks for any input you can offer…
Ditch digger in VT
Replies
Drainage is poor around the house and the roof is metal without gutters.
Well, you can spend a few hundred bucks on gutters and downspouts and downspout extensions and making sure you have positive grading around the house, or a few thousand on trenching etc.
In most cases, moving water away from the hosue (well past the overdig area) will solve the problems
I wouldn't stop with just roof gutters. The foundation is cracking in clay soil with no aparent drains. Clay can expand considerably from dry to wet because of the volumn of water it holds. Then let that water freeze and you've got one explanation for the cracks. Fail to solve that problem and expect a worse situation every year.
Trenching to the footers and adding fabric and stone is good but you also have to install a perimeter drain at the base of that and lead it out to daylight to leet gravity help you expell the water. If the site is one that makes this impossible, excavate a drywell (A hole filled with stone and lined with fabric) and lead the drain into the drywell. You have to give the water someplace to go. If you just put stone around the foundation, you make it possible for the water to run from the clay into the stone against the foundation.
Excellence is its own reward!
Piffin,
Good points. There is fairly heavy clay soil in much of the territory I do inspections in.
We get primarily two types of block foundation cracks around here from the clay soil. The first is generally about 1/2 way between the basement slab and grade, or lower. It's a horizontal crack caused by the wall bowing in because of increased moisture content of the clay. As it nears the ends of the walls, it stair steps up and down to the corners.
I've seen these cracks as much as 3/4" to 1"! (Sometimes axis of the bow is verticaal, with only minor crackijng but where the lowest course of block with a bottom edge above the slab has been pushed inward up to a couple of inches.)
The second type is usually a course or two belwo grade level and it occurs from freezing, expanding soil. I usually don't see those as much more tahn a hairline, up to about 1/16the, although I've seen more.
In most cases in my area, positive grading and good downspout extensions gets enough water away from the foundation to prevent further foundation problems.
My area is very flat. Any foorter perimeter drains are run to a sump and then pumped well away from the house. It is pretty unusual to be able to run perimeter drains to daylight.
This flatness has a small benefit, however. We rarely get runoff from one property to the next! (And sledding accidents are just about unheard of, around here!)
I usually suggest the least expensive approach because, around here, it usually works. If it doesn't then yopu call out the big dogs.
The situation and best approaches may well be different in other areas, however.
On this island, we have solid ledge overlaid with clay -various glacial tills and almost no topsoil. Ledge may be anywhere from one to twenty feet down. You can imagine the water pocketing we can have.Excellence is its own reward!
Thanks for the information, the good thing is that I have perimeter drains at the footing level already that are draining properly. I am more concerned about the pressure applied by the soil, do you think that just adding positive drainage for surface runoff will improve this ? I would like to do this right and hopefully have a dry basement as a result.
Thanks for all the feedback !
digging in Vermont clay... we have hills... runoff... springs.. lots of water !
Yes! Adding the stone will let the water get to the drains and building the plane up to slope will lead surface water away before as much of it can soak in.Excellence is its own reward!
I'm concerned about your idea about digging a trench and filling it with gravel. Unless you have a way to get the water out of that trench, you're just trapping the water up against the foundation.
Even if you do put some sort of drain in your trench, what happens when the drain is compromised?
I'm with the other guys in thinking that gutters sound like the place to start. Then make sure the water gets away from the house as far as possible. Underground drains to daylight are great if that's an option.
If you end up digging up around your house, go ahead and put something on the foundation like this stuff:
http://www.deltams.com/deltadrain/index.html
Be nice to your kids. They'll choose your nursing home.