# Concrete Gutters vs. French Drains?



## Thunder Chicken (May 22, 2011)

My house is on a lot where two boundaries are higher than my house foundation by about 6". I just had an old concrete patio (that was buried in my backyard for some unknown reason) removed and the yard was regraded. The grade is vastly improved, but there is an unavoidable step/slope down to the corner of the foundation. Another, probably bigger problem is that the 2 roof pitches have gutters that drain into this area as well. 

I have no water issues in the crawlspace as water does tend to find its way around the house to the downhill side, but it tends to erode a channel next to the foundation while it is doing so. Even with the new grading this is still occurring.

Basically all of this water needs to get routed around the house to the downhill side. The traditional solution is a French drain. There is some evidence that there is a clogged French drain in this area, and paying to dig it all up, re-install it just to have it clog up again doesn't appeal. 

I was thinking of eventually putting in a stone or concrete patio in this area of runoff, and I was thinking an alternative might be some sort of concrete gutter (like a street gutter) to prevent the erosion and guide the water around the house. Does anybody have any experience with this sort of system, any pitfalls, etc..? Obviously you have to watch the pitches and make sure that I am not eroding at the outlet. Is there anything else I should be thinking about?


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## AllanJ (Nov 24, 2007)

An underground French drain should be down at foundation footing level, that is, below basement floor level. But you may not excavate below foundation footing bottom level right next to the footings.

A concrete or brick surface gutter (also called a French drain) just needs enough slope so water will flow. I would say you can go as gentle as one eighth of an inch in a foot of run if that is all you can spare. A quarter of an inch per foot of run would be less likely to accumulate water due to ice buildup in winter and is also not that hard to work with.


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## Thunder Chicken (May 22, 2011)

Good point about the underground French drains - this flow is right on the foundation wall. There is really no place to set up an underground drain to intercept the flows before they get to that point. So surface drain it is, I guess. 

Follow on question - is anyone familiar with any commercial "block" system for surface French drains, or do I pull out the concrete mortar and start sculpting? :laughing: I have maybe 1'-2' of space next to the foundation to play with, about 10' long. Anything wider than that could be done but would require some digging.


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