Monday, March 10, 2014

Interior Basement Walls (Concrete Block) And Using Drylock



Do I need to remove ALL the paint from my basement walls before I paint them with DryLock? Or do I just remove the loose paint, mortar, dirt, etc. and clean them really well with TSP before I paint them?
When I bought the house in '99, before moving in we used a cheap waterproofing paint on the basement walls and floor. BIG MISTAKE!! A year or 2 later I started to notice large sections of the walls starting to bubble up. . .the paint on the floor did not stick for s@$t and gets all wrinkly looking if you spill water no it! All this caused the dreaded mildewy musty smell in the basement. Over the years I've improved the drainage around the house, I run a dehumidifier in the basement during the summer, and I've scraped all the bubbled up paint off the interior basement walls and some of the loose paint off the floor.
I'm not sure where to go from here to get rid of the musty smell for good.
I'm afraid if I re-paint the basement walls with a waterproofing paint that I will get the same bubbling. . . but I really need to get the musty smell under control. . .any suggestions would be appreciated.

Welcome to the forums!
A dehumidifier might help to get rid of the musty smell - maybe you need to run it more often
Have you pretty much stopped all the moisture infiltration? Are the walls damp?
Drylok works best if it's applied to bare masonary. It should be applied liberally - so all the pores are filled. TSP is a good cleaner but must be rinsed well - I only use it on the exterior.
I don't know if I'd go thru the the trouble of removing all the paint but the loose must be removed. If you currently have painted areas that moisture is passing thru, I'd try hard to remove the paint from those areas. Any missing or loose mortar needs to be replaced or at least caulked.

I'd also recommend scrubbing the walls down to remove any loose material.
Take a stiff plastic or steel bristle brush, wear a mask and goggles and scrub it all down, ceiling to slab.
Then sweep and shop-vac.

Musty smell is from mold! Make sure you are running a good dehumidifier tell RH gets under 55%.

Also, once humidity is finally down, you may want to spray the walls with bleach to kill any spores in the nooks and crannys.

Over the past week I did a couple things:
1) I did the tin foil test on the wall I think is giving me the most problems. After leaving the foil on the wall for 2 days, I was surprised to find that neither the outside nor the inside of the foil was damp. The wall was not damp either. I assume this is a good thing.
2) I'd say I've got 95% of the loose paint off the walls, but I have yet to wash them done with a bleach solution
3) I determined that my musty smell is not coming from the walls as much as it is coming from the cement floor.
4) the humidity level in the basement does not seem all that high, but I'll check if its in the 45% area
What we did way back in '99, before fixing any of the exterior drainage issues, was paint the walls and floor with a waterproofing paint. The paint stuck to the floor for about a year, and ever since then all it's been doing is trapping the moisture, seeping up from the floor, between the concrete and the layer of paint.
This past weekend I went to town and scraped a lot of the paint off the floor. The musty/mildewy small has gone down quite a bit already without even cleaning the floor.
Once I clean the floor, I should be in pretty good shape, regarding the smell.
The floor has a dozen or so hair-line cracks and one 1/8 inch crack in it. the seeping seems to be coming from just these cracks, but I've never had enough seepage that it caused standing water.
I don't think I can stop the floor from seeping without forking over a lot of money to a professional to fix the problem. Does anyone have a suggestion as to what to do with the floor, if anything? Should I just remove as much paint as possible, leave it unpainted, and give it an annual cleaning with a bleach solution?

Not painting the floor would probably be best. That way the humidifier can work at keeping the moisture level down and no moisture will be trapped under the floor coating.
Drylok makes a floor sealer [different than the wall coating] but I've never used it and don't know how well it would work.

Yeah I think you are right, I am going to just leave the floor unpainted.
I bought a new dehumidifier last night, the one I had was pretty old. The old one can not even compare to how well the new one works, I am glad I made the switch.

As far as the remaining paint on the wall is concerned, I have a short wall in my basement that was painted. Not sure if its drylok or just white piant. Was done by previous owner.
When looking at it the first time after I decided to drylok my basement, I couldn't see how I would get it all off. I called UGL and spoke to a technical inquiry rep. He said to definitely get all the loose paint off it and give it a good cleaning, but what I didn't get off wouldn't be a problem. He also said the UGL warranty does call for a clean of paint surface when applying the drylok, but it would be hard to tell after apply two coates of drylok. Not sure how good the UGL warranty is...it might be just repayment of the purchase price for the drylok.
Anyway, that's what I was told by UGL. My basement is mostly dry though. Google UGL and give them a call. They were VERY friendly and returned my message same day.

I've never contacted UGL about their warranty but rarely does a coating warranty cover more than the cost of the product. IMO a warranty is not much more than a sales guide to help you determine the quality of the product.
Any failures I've ever encounterd with drylok where either related to improper application [usually too thin] or the moisture problem was too great for an interior coating to stop. It is always best to stop the water on the exterior! although it isn't always practical

Originally Posted by notlohdahc
Over the past week I did a couple things:
1) I did the tin foil test on the wall I think is giving me the most problems. After leaving the foil on the wall for 2 days, I was surprised to find that neither the outside nor the inside of the foil was damp. The wall was not damp either. I assume this is a good thing.
What is the tin foil test???

I'm not familiar with the 'tin foil test' but I assume it's similiar to taping a section of plastic to the floor to check on moisture. Moisture can't evaporate into the air when covered by plastic - if the plastic stays dry, then there is no moisture problem.

Tape a piece of plastic to the floor?? What kind of plastic? Saran wrap? Trash bag? Something like that? I'm guessing you tape all 4 sides to make a close to air tight seal right??

Tape a lawn and leaf bag, cut it down the side and bottom to open it up, tape it entirely down, leave no openings.
Leave it for a day or two and then lift it up. If it's wet, you've got moisture coming up from the bottom.

After spending a couple weekends in my basement scraping the paint off the floor, I've got it pretty much done. I figure, any paint left on the floor can stay there because it must have a pretty good bond with the concrete.
My musty smell, is all but gone, EXCEPT when it rains. I don't get any standing water or any obvious moisture spots on the floor or walls, but the musty smell is present(just not as strong as it was before).
I did not want to re-paint/seal the floor, but it looks/smells like I have to, if I want the smell to go away completely.
What are the proper steps to take to paint/seal a basement floor properly?
If you read my original post, that started this thread, you'll see I obviously did a rush job the first time which got me into this mess in the first place.
I want to do it right this time so I don't end up right back where I started.

Have you already applied drylok to the walls?
IMO it's best not to paint the floors but if you must - I'd see about getting more info about drylok's floor sealer.

Does Drylok work only on cement, or would it work on fieldstone and granite foundations? I think most of the water that gets through fieldstone foundations comes from the spaces between stones, so I'm thinking I need to use waterproof cement rather than drylok. Any advice?






Tags: interior, basement, walls, concrete, drylock, coming from, foil test, loose paint, musty smell, paint floor, basement walls, musty smell, waterproofing paint, with bleach