A client asked me to bring in some topsoil to improve drainage on the east side of her home.
The exterior is cut sandstone over stud walls on a concrete block crawlspace.
I was concerned about raising the grade against the wall and crawl vents and looked to see if I would cover the weep holes. There are none.
Why not??? Does the sandstone let moisture move out of the walls?
Replies
likely that water is running down inside theblock foundation wall and then movving laterally when it hits the footing
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How old is the house?
In my area (NW Ohio) there are a lot of houses with brick and stone veneer w/o weeps. (Especially older) Most don't have visible problems, but some do. You have to get in the crawl and look carefully.
Usually when it's a problem they also didn't step down the foundation to have the veneer terminate below the sill plate. Check at the crawl space vents to find/confirm this.
That the client wants to improve drainage suggests she has some specific concerns.
What are they?
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In my experience this rarely causes a problem. The amount of drainage is usually so minor that the water, if any, drains into the block cores and just evaporates.
Not a block or brick guy myself. But I attended a Masonry Institute Conference a couple of years ago as a designer. I attended a couple of seminars on masonry detailing and the guy presenting (a guy who really knew his stuff) couldn't express enough the importance of regularly spaced weeps. horizontally and vertically along the wall. He also stressed how important it was to try and get the masons to be as clean as possible on the back side and minimize mortar squeeze out that would fall to the bottom and plug the weeps.
The issue is most important in commercial construction where steel stud is often used as the backup wall. He showed numerous examples where steel stud had corroded quite extensively over a short span of time (couple of years). The corrosive salts in mortar when mixed with moisture can be a toxic mix for steel studs.
That's all true. I'm talking only about block walls where you have an easy path to drainage. If you have a lot of water getting through a stone or brick job, something else is wrong.
My choice would be to dig out for drainage rather than add.
So would you did for more slope or to bury drain tile?
This lot is flatter than flat and a little below grade for roads and property nearby.
I did it for slope. 6' back and ended with a swale on one side. I am on a 60' wide flat city lot.
I'm not going to comment much on the absence of weep holes.
You need to look around for a drain tail (s) for the CS (crawl space) and make sure you don't cover and/or crush it. (if there is one) This would start at whatever the lowest part of the CS is and go toward the lowest corner of the lot - however slight it may be. Putting dirt around a foundation can really help, but having the exterior grade around a house higher than the CS grade can create a "swimming pool" effect in the CS.
Not that this would effect you, but here building code requires a positive drain out of the CS if the CS grade is lower than the exterior grade. "Positive drain" = drainage system.
My thought would be that if there is an issue with CS moisture (which may be contributed to by the no weeps situation) if the CS moisture gets worse after you do your work the HO could feel it is "your fault" that the situation was worsened - even though he/she has asked you to perform the specific task of regrading. If you are adding dirt to the high side of the foundation this would be less of a concern.
Don't we here at BT just bring lots of good news? ;-)
BTW - if the lot is that flat I'd use a laser level to evaluate the situation before doing the grading.
Thanks Matt.
Thanks ALL for your responses.
John
The house I'm in now has some drainage issues. One of the former owners built up the grade near the house to improve drainage away from the house.
But it brought the grade above where it should be in relationship to the house.
I think this is common because people don't want to go to the expense, or work, of exporting soil off the property.
I have a truck and a strong back so getting soil off site isn't so much of a problem. Most people don't.
Will Rogers
I used a shovel and a wheelbarrow to remove. I agree remove don't add.