Is it a good idea to paint cement sealer all over a humid basement?
Or does that just trap the water in the cement and hasten it's
Our basement is very damp, with the humidity seeming to seep through
the cement. Our house was built in 1978, and they don't appear to have
done exterior sealing on the outside all the way around the outside of
We'd like to pull up the skanky carpet, seal it, and tile over it,
but I was wondering if the cement sealer on the inside might have
Waterproofing paint can slow influx of water, but is a very temporary
solution, as no coating can resist hydraulic pressure of the water.
First you should address the moisture problem, then consider your
decorating/sealing/tiling activity. Generally, moisture probs can only be
dealt with with correcting the drainage situation around the house, by
redirecting rainwater runoff, downspout drainage, french drains, and
re-waterproofing the exterior of the foundation, after excavating.
Thanks for responding. I'd like to address the moisture problem, but
I'm not entirely sure where to start. It's not strictly speaking a
drainage problem in that there are no obvious leaks that are exacerbated
by heavy rain. In fact, in big storms, the basement is remarkably dry
(with the exception of a corner in one garage door where water leaks in).
The larger problem is just a pervasive humidity down there. There
just always seems to be a fair amount of moisture wafting up through the
concrete. On really humid days, you can move larger objects in the
garage and find small pools that condense from the humidity. The carpet
currently in the basement is pretty moldy.
As I say, it doesn't appear to be a leakage problem but a pourous
problem. For some reason, moisture seems to filter pretty easily
through the walls and floor.
If it were a downspout problem, I could dig a couple of trenches, lay
some pvc, and run it out a ways. I just don't know enough to understand
the dynamics of the humidity getting through.
I have exactly the same problem in our "new" 140 year old
house. Basement was dry as a bone all fall, winter and spring despite
record snowfalls and one of the rainiest springs on record.
Soon as summer humidity came, basement started smelling musty, pipes
had small puddles of water under them from dripping condensation, and
parts of the basemen floor (not the walls or even near the walls)
appeared damp or even had a think film of water.
I too wonder whether adding drainage to this old house would even help
or whether I just need a better seal -- whether paint or new layer of
Best deal with the problem from outside as what another person has
already suggested. However, there is a limit of what we can do from
outside because we are not likely to dig out the house foundation to do
the full course work. This means after we have done all the simple
things that we can do to keep water away from outside, we may still
feel high humidity level in our basement. I am not sure why. I have a
feeling that the moisture is passing through from the soil around the
house through the porous concrete blocks of my house foundation.
Paint the basement wall and floor with sealer may help. But you cannot
paint over the area of the floors that you may need to finish with
floor tiles later (the floor tiles won't stick to a painted surface).
This means if you want to put floor tiles directly on the concrete
floor in a later day, you cannot paint that area. This also means that
moisture can get through from that area. And that is exactly what
happens to me. Finally, I need to use a dehuminifer to fix the problem.
Sounds like the problem is humidity, as opposed to visible water
leaking into the basement. I would make sure all external grading
slopes away from the foundation and leaders take water as far away as
practical. Check to see what's really going on outside during a
Then I'd consider using a Dry Lock type product and/or a dehumidifier.
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