Sealing / Finishing stone foundation basement

[jpoder]

My house (~55 years old) has a stone foundation (~18 inches thick of HUGE stones and concrete) originally it had about 2 inches of concrete plastered over the stone walls with some type of thick paint on top of that, but in many (most?) places the paint has chipped off and some of the concrete plaster has crumbled away. Other parts of the basement has a iron mesh with concrete type plaster spread over it (metal lathe?) but that has sort of buckled away from the wall in some places and overall there is some eflorescents (sp? dry white powder or foamy looking stuff) around the walls in various places. I don't get water in the basement (no sump, even) one wall gets a tiny bit damp during hard rains, but i think this is due to drainage in the yard, which I can correct. The basement feels a bit damp, though. Other than that the walls are solid (I guarantee...I painfully drilled for a drier vent pipe through the D*&m thing!)

sorry for the long lead-in, but here's my question:
QUESTION: What can I do to seal the walls to prevent any more of the paint or "plaster" from crumbling away and to get rid of the last bit of dampness? Can I paint on something like DRYLOK? how do I prep the surface? should I seal the floor slab when I do this too?

Thanks in advance for your help!

jim

[Maren Voss]

I have been searching the internet for information on how to coat our dry stone basement walls that were previously coated in some sort of plaster/insulation/concrete substance. This posting is the only thing I have found that begins to address that question, but it hasn't gotten any replies. Does anyone know whether these dry but crumbling stone basement walls can be cleaned well enough to be coated with a drylock or elastomeric type of substance?

Thanks

[GrammaSphinx]

All I can say is what we've done, to the field stone/cement basement walls of our son. We used the pointy end of a trowel to dig out all loose debris between the stones and applied/pushed in fiberglass cement. We were advised that the walls didn't have to be completely dry when we used this cement. We did wait for the walls to dry up some though. It was a tedious job and I just learned that there is a corner of the basement where the oil tank is located left to be done that no one returned to finish. Last week there was a near flood in our area. Our son lives part way up a hill. We did get some water into the basement, but it was only from the areas we didn't repair. ...and from dirt floor areas. Some of the floor has slabs of stone on it.

It sounds like someone did some parging of the basement walls in the original question above. We were thinking of doing something like that, but when I read the above note, we're cancelling those plans. What a mess!

Well, back to the basement to finish the job and inspect the wall for other areas to repair.
Hope this was helpful.

[jpoder]

Well,

I'm glad to see that my thread lives on... Given the lack of responses to my original post, I went it on my own using my common sense (oh no!).

I put a dehumidifier in the basement about 7 months ago and that REALLY helped. I chipped away all of loose/crumbling concrete and paint and used a very stiff wire brush on the entire wall (lots and lots of work, not to mention the mess!) using morter/concrete patch that was recommended for walls, I repaired the worst of the cracks and holes. Finally I used drylok (2 coats). putting this stuff on is quite a bear! it's a consistency somewhere between pancake batter and peanut butter. some places I was able to roll on with a 1" nap roller, but had to use a brush to get into the crevices and cracks. LOTS of work, and my coverage was on the low side (~100 sq feet per gallon). the walls dried very rough (think 60-80 grit sandpaper). Not really happy with that, but oh well...I may try to recoat with latex paint. Anyone have other suggestions? A recent trip to Home Depot I found that Behr has released a dry-lok competitor that they claim works better and dries smooth. I haven't used myself, but I will try it out (I still have half of my basement to go!). I ended up using a concrete primer and stain on the floor after cleaning it using muriatic acid (I think). After I got that done, a buddy offered me a whole bunch of 2 foot carpet squares that were left over from a job. that turned out awesome! my son now loves to play in the room of our basement that I finished!

Good luck with your basement! please keep us informed!

Jim

[mbales]

Thanks for describing your approaches/experiences - have there been any further updates on this sort of work? I am about to embark on the same project - stone foundation with crumbling parging all over that I want to seal up against leaks (none so far that I know of) before framing/finishing the basement.

[Magesse]

I just this afternoon finished painting my 1100 sq. ft basement walls with the Behr #875 Concrete & Masonry Waterproofing paint. It took about 6.5 gallonsfor a very thick coat. I had first primed it with 11 gallons of the BEHR Enamel primer/underlayer which is Latex based. (The Behr waterproofing is $107 per 5 gallon container as opposed to $96 for the the DryLok and it was very easy to use!)

These cinderblock walls were a mess - full of efflorescence (the white crumbly stuff), gouges, bug holes etc. but after wire-brushing, liberal patching with concrete, followed by the above treatments they look beautiful. The Concrete & Masonry paint went on like a dream with a 1" nap roller, but not nearly so well with the 3/8" one. We only needed the brush for cutting in.

I highly recommend both of these products for ease of application and quality of the final appearance. I'll find out tomorrow how it looks when completely cured but the results are promising at 12 hours in.

A WORD OF CAUTION: I was shocked and VERY dismayed to discover that wirebrushing the concrete by hand produced about 4 times the mess of jackhammering up the entire circumference of the basement. When I was at Home Depot later, they did have some products that were supposed to help with that problem. You might want to check them out. I'm gonna be vaccuuming up that super fine grit for days!:mad:

Hope this helps.

[GrammaSphinx]

All I can say is what we've done, to the field stone/cement basement walls of our son. We used the pointy end of a trowel to dig out all loose debris between the stones and applied/pushed in fiberglass cement. We were advised that the walls didn't have to be completely dry when we used this cement. We did wait for the walls to dry up some though. It was a tedious job and I just learned that there is a corner of the basement where the oil tank is located left to be done that no one returned to finish. Last week there was a near flood in our area. Our son lives part way up a hill. We did get some water into the basement, but it was only from the areas we didn't repair. ...and from dirt floor areas. Some of the floor has slabs of stone on it.

It sounds like someone did some parging of the basement walls in the original question above. We were thinking of doing something like that, but when I read the above note, we're cancelling those plans. What a mess!

Well, back to the basement to finish the job and inspect the wall for other areas to repair.
Hope this was helpful.
2008: We finally got the time to finish the basement. Here's what a professional, who is a friend, told us to do. Per 1 bag of fiberglass cement plus 1 bag of regular cement; mix the two together dry; then mix with water as usual. (A bag of fiberglass cement and regular cement are not of equal amount, so it's not a 1:1 mix) Apply with Trowel to sides of basement walls generously and allow to dry. If it needs to be redone, do it. The goal is to completely cover the sides with a smooth finish. Apply Dry-Lock on top of the sealed sides as directed.