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I have had a new addition put on to the back of my 90 year old home. The old basement has block walls and a ceiling height of 6’4″ and I wanted the new basement to be a little more “finishable” so I went a block deeper.
Now the problem. Since completing the work, I have had a problem with water entering the basement after a good rain. The water is entering at the bottom of where the new masonry wall meets the old masonry wall. It turns out that there is no footing below the old foundation walls. By going down another block, I have exposed the soil below the old wall and water seeps in. This is not a load bearing wall so I am not particularly worried about the structure. But I would like to stop the water and support the wall a little.
The exposed soil (above the new slab) is about 3″ high and 25′ long. Does anyone have a suggestion on what material/techniques to use. I have already addressed the normal basement water solutions (gutters, grading, french drain was installed under new slab at construction)
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If my visualization (3" high soil is where the old and new floors meet?)is correct, you need to pour yourself a 3" high concrete wall 25 ft long. Easiest DIY way I've found to get a watertight bond between old conc. or block wall and floor is to mix a soupy grout and power wirebrush (5" cup brush works well on angle grinder)it into the bonding surfaces. Be sure to leae no voids in the short wall. Possibly add an additional drain at teh floor intersections. The "support the wall" phrase is confusing as it conflicts with the visualization described above, so maybe this is all wrong. .
*The original foundation wall is located at the end of the old basement floor. So pouring concrete would actually better support this wall be encasing the dirt under the wall (as compared to leaving it exposed. Do you think that a soupy mix will really seal this joint or is the concrete going to shrink away and leave a gap. I know that this is also bonding agents out this that I could use.I am not really sure what you want me to do with the wire brush. Do you mean just clean the wall before pouring... or are you suggesting using it to somehow pump the concrete towards the wall.Any suggesntions on the type of grout. Would a thin set work?
*The wire brush is wet with the soupy mix (straight cement and water, no sand)as a bonding agent (or use a commercial mix). The wire brush then gets you a good bond so the concrete does not crack away from the floor/wall when it cures. The brush essentially scratches the new wet cement into the old, providing a good bond and assures surface wetting - only other sure way for bonding is to 100% chip away the old to a clean surface. The wet power wire brush method is the only cheap DIY way I've ever gotten a good bond with on old surfaces - never have tried a 4000+ PSI pressure washer which I've heard works also for getting a good surface to bond to. Use a fairly rich mix with only pea gravel mix (NOT soupy)for the short wall concrete.
*I would drill and dowel above into wall and down into pad, and use a bonding agent directly on surfaces and in the mix.
*Wow! Do you really think I need to dowel just to seal up the wall? I thought doweling was structural.
*Well its not that time consuming ,drill a few holes,install some dowels dipped in epoxy, and there you go. My main concern would be the movement constantly cracking all your seals/seams,hence the dowels. You could also use fiber cement, with the small amount of cement you will be working with there will be no big expense, might as well do it full proof. Or should I say better, sealing from the inside is a tuff battle.
*Wow! Do you really think I need to dowel just to seal up the wall? I thought doweling was structural.
*b WBA At Your ServiceAll well and good, but the water is going to win and find a path through a fine crack somewhere anyway. You need to get to the source of the problem and that is the water flow and the resulting pressure buildup. I don't know what you mean by a "french drain", but if it is only a stone filled pit under the floor, I'm sure it's already full of water. You need to pipe the water either to daylight or to a sump pit. Worry about redirecting the water first, then underpin your wall.
*I have a footer drain around the outside of the footer (three sides of basement; not the common wall) that leads to a sump in the basement. I also have a french drain in gravel under the slab that leads to the sump. No water ever comes out of the slab drain but I do get a good amount from the outside footer drain. As both of these drains are below (5-6") the exposed soil, I feel pretty sure that this is just surface water working its way down. The water from the exposed soil is a slow trickle and continues for several days after a good rain and then stops.I think that the short wall idea will work as long as the new concrete seals to the old wall and to the slab.
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I have had a new addition put on to the back of my 90 year old home. The old basement has block walls and a ceiling height of 6'4" and I wanted the new basement to be a little more "finishable" so I went a block deeper.
Now the problem. Since completing the work, I have had a problem with water entering the basement after a good rain. The water is entering at the bottom of where the new masonry wall meets the old masonry wall. It turns out that there is no footing below the old foundation walls. By going down another block, I have exposed the soil below the old wall and water seeps in. This is not a load bearing wall so I am not particularly worried about the structure. But I would like to stop the water and support the wall a little.
The exposed soil (above the new slab) is about 3" high and 25' long. Does anyone have a suggestion on what material/techniques to use. I have already addressed the normal basement water solutions (gutters, grading, french drain was installed under new slab at construction)