Concrete question

[cmac2012]

I have a client with a house on a bit of a hill (built in 1925) which is experiencing some cracks in the stucco in various spots. Today I patched a large one at the bottom of the wall in this photo, up to and around the near side of the outcropping. Large as in one to two inches wide. Might be a chimeny above, not sure, below that is open space in the basement, so might not be a chimney, I don't remember the layout of the room on that floor, might not have been in that room ever.

Anyway, you can sort of see the little broomed pebble surface panels to the left of sidewalk sloping toward the house. In the corner where it meets the outcropping/chimney water collects, this I found when I hosed the stucco patch dust off the sidewalk.



Some of the wood bordering the concrete panels in the corner is spongy, no surprise, it has regular and long baths during the rainy season. They have water on the floor and walls below that spot in the basement during the rains. Not sure if any will continue to leak past the rotten wood. Doesn't seem good to allow a regular puddle at that spot.

My thought is to jackhammer those suckers out, remove the wood of course and pour some kind of new concrete with slope enough to keep water out of that corner. I've not done a lot of this, I'm wondering if I need to put one of those oily fiberboard things between the new concrete and the sidewalk. I gather that some movement can happen and a slightly flexible barrier is a good thing.

I used to see that stuff all the time in NM when I was a kid, seems like it's not used that much these days.

I know about using rebar pins to connect, what I don't get is if I should use the pins and the fiberboard, holes put in the latter to slide it over. Seems like an odd idea suddenly. I read once about some coating one could put on the existing concrete before pouring that could help with a mostly watertight joint.

[engatwork]

Could movement of the foundation have caused the cracking? Rotten wood allowing movement?

You have got to get it where it will drain away from the house. I'd try to get the broomed peeble surface panels out of there and go with drain tile. Any drop in slope away from the corner?

drain tile

[Botnst]

I’m facing a similar issue but with new construction. Architect put drain tile along the exterior wall and a moisture barrier between the wall and gravel for the drain. Dunno if I explained that right.

Anyway, the architect sought first to capture water and redirect it. Secondarily to put a barrier between wall and soil. We get about 45” of annual rainfall.

[oldsinner111]

ask home depot,lowes,or ace hardware. Once rot,or cancer in wood starts,cut it out.You can stab onto it,and fiberglass over,then concrete

[barry12345]

You might form a surface drain in the area of the stone panels in concrete. After removing them If you can slope it along that wall to someplace lower.


I might pour concrete and use a 3 inch piece of abs pipe to get a drain trough shape established. I do not think the volume of water is great. I have had decent luck with some basement waterproofing mediums to get a seal between the new concrete trough and the existing concrete. . The stuff seems to bond to clean surfaces. You do not want any water entering between the pathway and the trough junction.


This approach of course depends on what the physical grades are like around that area. I use a five thousand pound concrete strength as it is waterproof. Looks like a very small volume job.

[t walgamuth]

I'll comment later after thought.

[engatwork]

I'll be following this thread. I'm considering building a ~1500 sq ft earth bermed house and want to see what best answer is.

[cmac2012]

Originally Posted by engatwork

Could movement of the foundation have caused the cracking? Rotten wood allowing movement?

You have got to get it where it will drain away from the house. I'd try to get the broomed peeble surface panels out of there and go with drain tile. Any drop in slope away from the corner?

drain tile

It's not apparent in the pic but the sidewalk has a good slope forward from the vantage point. Maybe 20-30% slope. The foundation does seem to be moving and has been for a while. Seems that houses on hills move downhill, probably slower than glaciers, but they do move. Most of the cracks above were 1/4" or less wide, the one at the bottom I filled yesterday was mostly where large pieces of stucco but in several spots I could also see and feel jagged cracks in the foundation that extended downward an unkown amount. Quite a bit of the stucco patch was taken in, lot of room in those cracks IOW. I should have taken some before pics.

I think it not unlikely that this alone will stop much of the leak in that area. Having the slope direct the forming of a small pond above a crack in the foundation that large can't be good.

The problem with using drain tile is I'd have nowhere to send the water. I'd have to tunnel under the sidewalk and as it's up against a 8" or so concrete retaining wall on the other side with only a foot or so of soil between it and the property line would be a huge, near impossible job.

This is one of those houses with no eaves. I'm guessing it's a flat roof. The chute feeding the downspout protrudes from the wall about a foot from the top. Water is always going to find this spot.

[t walgamuth]

I'd probably caulk all cracks with a tough but elastic caulk. obviously water needs a place to go away from the foundation so you are on the right track there. an outdoor slab needs to be able to float away from the building without resting on hard material that would cause cracks. The movement is greater here where it freezes. Without freeze action the only force would be settlement.

[barry12345]

I might even waterproof the area as much as possible and install a drain into the basement. Depending on the elevation right into the sanitary drain even if it is illegal. The ideal of moisture accumulation in any wooden structure is concerning. Water volume should be not too great. Unless the whole driveway is draining to that point. I guess to be really legal it would have to go to a sump and pumped out somewhere else on the property.

[INSIDIOUS]

Originally Posted by engatwork

I'll be following this thread. I'm considering building a ~1500 sq ft earth bermed house and want to see what best answer is.

Geo-textile fabrics. Tiger drain was a nice one decades ago, but look around. Steer the water to where you want it to be. End of issue

[barry12345]

Flat property is usually harder to work with. When drainage problems exist. Unless the excess drainage can be fed into a utility. It has always been a problem.


In the day things like dry wells were often constructed.

[vwnate1]

I was hoping some one would mention these, I remember them a lot but I'm old and have no idea if they're still legal much less in use .


I once had a tiny house in PO-mona, Ca. that had been built as the sales office for a post WWII housing tract then when all the lots were sold they kinda - sorta added on a dog legged kitchen and sold it as a two bedroom home....(it was cheap & nasty but I only paid $49K for it) .

It was _slightly_ lower than the sidewalk so drainage was often a problem, after I gave up living in it and rented it out my best tenants 4 year old son discovered an abandoned dry well behind the house when he fell into it ~

Luckily he wasn't hurt and the tenant drove a Ready Mix Concrete truck so he just filled it in with some left over materiel .

[t walgamuth]

What I know as a dry well is a large tank with holes in it. You run your sewer into it and it takes the place of a finger system. It works in sand probably not in less permeable soil. We had one when I was a kid. It was built of concrete blocks laid with a space instead of vertical mortar joints. It was circular and it could be either capped with a slab or brought in like an igloo.

I am not sure if they are ever used any more. It might not even be legal.

[engatwork]

Flat property is usually harder to work with.

I don't know, I was watching one of those shows like "building giants" the other night and they were pouring a 4' slab to top off a building overlooking Central Park - 1550' up. They said that once the concrete hits the pump truck it takes 20 minutes to get to the top. They did not mention what they drained the pipe into upon completion of the pour.