Lower lever remodel
Need advice on redoing a lower floor, which is partially below grade. One end of the house is at grade and the other is 2’ below grade.
Current condition:
¾ of the area already has a slab but there is no moisture barrier below the slab.
The slab does not meet the stem wall (about a 6†gap).
The concrete slab is old and brittle and it has highs and lows.
Perimeter Foundation (New concrete footing and stem wall with French drain on the outside)
House is located in California Northern Bay Area
Soil is loam with a few patches of clay.
What I would like to achieve:
A watertight lower level living space.
A level platform to rebuild my walls on.
I plan to install radiant heating in the floor (in the concrete or in the subfloor?)
I would like to install wood floors if practical
Any suggestions on water proofing or if you have experience in this type of remodel please let me know the techniques you feel are best suited to achieve the goal. Any good books on the topic?
Thanks
John M
Edited 7/31/2002 12:52:47 PM ET by john m
Replies
The first rule of waterproofing is that nothing is waterproof.
Keeping that in mind, the second rule is to give the water someplace to go.
Considering everthing else you state, I think that I would break out the jackhammer and get rid of what is there now. Teh you can dig more and better drains in, place good gravel, compact it, set your Hypex tubing for heat and pour a new floor.
I already have exterior drainage installed at the foundation footing. I've heard some people mention installing drainage on the interior as well. Is installing drainage interior of the foundation a good idea?
I would think it would be beneficial but I want to make sure I wont be causing other problems by doing this.
John M
I can't think of how it might hurt. You apparently have a daylight basement so it shouldn't be hard to run it to open. You'll need a trap in the line and wire mesh at the end to keep critters out. Pour eco-friendly antifreeze in the trap occasionally to keep wind and/or odors from blowing up in. Then you have a way for water to go if it should get in through the wall.
But the more important drainage that I meant was under the slab. The soil there should be well compacted sand stone mix. I like at least 12" here. I don't know just what your native soil will be there. You mention some loam and clay, neither of which is a good base to build on. Since you describe an unprofessional slab now, I assume that whoever poured and finished it didn't do a professional job on soil prep either.
Removing the existing may even let you find a way to increase headroom. Too many basements feel like a coal mine because of low overhead. Slab up and pipes down in an eight foot wall leaves about 7'2", if you're like many, and if you add maore concrete or gypcrete above the slab for heat you lose even more. That's fine if you like living in a pancake...Excellence is its own reward!