VCR Ate My Copy of The Half-Assed Approach to Foundation Repair
February 9, 2014 5:00 PM Subscribe
The decades-old parging/plaster on our basement walls is scabby and peeling. The concrete itself is crumbly in places and there are a couple of cracks. It seems to me that the solution to my problem is to remove the old parging/plaster, fill the cracks with hydraulic cement, and patch the crumbly parts. But I'm less clear on the hows, whys, and whens.
posted by Alvy Ampersand to Home & Garden (6 answers total) 2 users marked this as a favorite
I guess my options for removing the old parging/plaster are using a solvent to dissolve it or a wire brush. Not a fan of the solvent, due to ventilation issues and our cats, so I'm leaning towards cordoning sections of the wall with poly sheeting to keep dust from getting everywhere, putting on a respirator, and scouring it.
Question 1: Is there a good time of the year to do that, or optimal conditions, temperature/humidity-wise? It's currently 15C in the basement, and around -20C outside. Will that make the cement more fragile if subjected to scrubbing, or make the crumbly parts crumblier?
Question 2: In a similar vein, what are the optimal conditions for applying hydraulic cement to cracks? Cold/dry, or hot/humid?
Question 3: Cleaning/clearing out the crumbly areas and patching. Would hydraulic cement also be the thing to use here? Does it require driving some spikes into the wall to give the patch material something to hold onto, or do you use some sort of lath, which would presumably also need to be anchored?
Question 4: What do we do after that's all done? Due to the smaller space and layout, it's not likely we'd be able to put any sort of code-approved bedroom down there, but it would be nice to not have it looking like a dungeon. Should a new coat of parging or sealant be applied to the walls, or a membrane so moisture doesn't get trapped in the concrete (Presumably the cause of the crumbliness), or a product like DRIcore's wall application?
Miscellaneous Basement Facts, Many of Which Are Probably Negligible, But If I Knew What Was Relevant And What Wasn't I Probably Wouldn't Be Asking My Question In The First Place:
- House is 100 years old
- 3/4 style basement with a crawl space
- Walls are poured concrete, about 7' high
- It looks as though the house originally rested on the ground, or was much closer to it, and at some point was jacked up and the 2' to 3' that's above ground was added to it
- Frost line here is considered 6' minimum, soil composition mostly clay I think
- Despite the below ground part of the walls only being 4' to 5' high, the 2' depth of the sump hole leads me to assume that the footers/floor are a similar depth/thickness, which gives a total depth of approximately 7'
- No evidence of shifting
- Sump hole only has one outlet, presumably it drains to the storm sewer
- No backflow valve
- No weeping tile/french drain
- Cracks in basement wall correspond to a downspout on the exterior wall that drained right beside the house; when we moved in I attached another length of downspout to direct water away, and there hasn't been any water since
- Presumably no membrane on exterior of basement walls, any coating that's been applied is probably long gone
- We run a dehumidifier in the summer