I'm trying to finish a room in the basement. The plan was to frame some studs, hang drywall, the usual procedure when building a room. The thing is, it might be out of budget to buy everything I need for that while keeping everything moisture free. The studs, the insulation, the vappr barriers, flooring, etc.

My question is: could I not just drylok the cement walls and floor? Insulation and heat loss isnt really a big problem for me. I could just drylok the walls so it looks painted and put a rug down for a simple room right?

I should also add that there haven't been any moisture problems in the past. I just don't want to create any new mold problems.

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    If your basement was built with a proper vapor barrier you might not even need Drylok. Just a simple primer/paint that sticks to masonry (but isn't designed to waterproof) might be sufficient. – Shimon Rura Jan 24 '18 at 16:56
  • Hard to say with out knowing what you already have - was the basement done right the first time .. however if you put the vapor barrier in - you will not hurt the installation, not doing it - or skimping you might have an issue and regret it, so if for the sake of the budget you need to do it in stages - do it. Look at craigs list , habitat for humanity restore or surplus sales to see if you can find some materials for a lot less. – Ken Jan 24 '18 at 17:41
  • There is no vapor barrier Because the basement is unfinished. I want to avoid putting up studs and insulation. I'm just asking if drylok on the cement walls and cement floor with no additional studs, drywall or ANYTHING else will be sufficient. – Kai Jan 24 '18 at 19:07
  • I wasn't clear, what I meant was vapor barrier or moisture barrier under your slab and on the outside of your basement walls. This is common practice in new construction nowadays and will make the basement easy to finish. – Shimon Rura Jan 24 '18 at 22:38

I would not install any vapor barrier in a basement. If you do paint the walls make you use a paint that will allow moisture to transpire through the wall.

Mother Nature has an unlimited supply of moisture so there is no way you can prevent it from entering the basement. You just want to make sure it is allowed to dry to the inside. If you trap it with a barrier it will cause mold, mildew and eventually fail.

Read the articles on this site regarding vapor barriers. Especially in basements. Like this article from fine homebuilding reprinted here. The number one mistake is "One: Vapor barriers on basement insulation will rot your walls".

I would just paint the walls with a flat latex and stain the floor. Or you could stain both and let the walls breathe even more.

Edit from tahwos' comment below: Should probably add the benefit of properly graded exterior slope, back-fill that can drain adequately, and working gutters, to round out this answer. A correctly installed and maintained basement, is a dry basement.

Good luck!

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  • Thanks I appreciate the advice! So am I mistaken in thinking that drylok is not a vapor barrier? Everyone keeps focusing on the vapor barrier so it seems like everyone is saying drylok IS a vapor barrier. In another thread, someone mentioned to not put things on the floor like laundry because it will risk mold. Thisbis if i drylok the basement. If I do like you said and paint later on the walls and stain the floor, should I still not put anything on the floor? – Kai Jan 25 '18 at 16:21
  • Drylok and other products like this market that you can seal out the moisture from the inside. They work for a time but Mother Nature has an almost infinite supply of moisture and eventually they all fail and begin to peal off the wall. If you proceed from the premise that you have to allow the wall and floor to dry to the inside then you can keep the area fairly dry and mold free. If you trap the moisture that is where the mold loves to grow. This is why I advise against carpet or vapor barriers in a basement. – ArchonOSX Jan 25 '18 at 16:55
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    Should probably add the benefit of properly graded exterior slope, back-fill that can drain adequately, and working gutters, to round out this answer. A correctly installed and maintained basement, is a dry basement. – tahwos Jan 26 '18 at 1:20
  • I don't use vapor barriers /wrap or on insulation in basements but do find epoxy sealing lasts and really reduces basement humidity, floor sweating the first one I did was over 20 years ago and it still looks like new no chipping or flaking I know this because my daughter lives in that house now – Ed Beal Jan 26 '18 at 23:22

Do not Drylok the floor using the original or extreme waterproofer - it will fail, it's not durable enough for floors. You can use Drylok Clear (might have been renamed Drylok Floor and Walls, or else that's just a similar product by Drylok that my store changed to recently) for the floors, or a penetrating concrete sealer such as RadonSeal.

Don't use Drylok on hollow block walls without drilling weep holes into the voids in the bottom course of blocks, or any water that makes its way into the block will exert hydrostatic pressure on the thinner walls of the block, potentially causing failure (it takes a lot less pressure to break 1" thick concrete than 8" thick concrete). Please note that the weep holes will admit water into the basement, if necessary, but this can reasonably be arranged to be below the parts of the wall susceptible to water damage. Drylok is fine on poured concrete walls.

If you have no history of moisture issues in the basement, you can forgo the Drylok - vapor barriers will be cheaper and easier than proper application of Drylok (which requires thorough cleaning, acid etching, and at least two coats with coverage of only around 100sqft per gallon (1/4 that of normal paint), according to its instructions). I'd recommend poly sheeting if you have humidity concerns, although it's probably better to just run a dehumidifier - even with sporadic moisture problems my dehumidifier keeps the humidity in the basement below 60% in the summer. If you just want a slightly finished look, you can absolutely just paint the wall.

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