I have a concrete block wall in my basement that is chronically damp
inside. I had a contractor over to look at the situation - whether
the outside of the wall should be resurfaced, etc. - and he thought
parging the concrete block before finishing the wall, would be
enough. He said a layer about 1/8" thick. He said they use a
compound with fibers in it.
THe coat couldn't be thicker than 1/8" because there's a staircase
going down alongside the wall, so space is limited.
The parging would be for waterproofing, not for cosmetics. It can be
rough, because I'm building a wall over it.
Is this a reasonable job to do oneself? With what kinds of tools?
What kind of cement should one use for waterproofing?
There is no magic covering to do what you want, at least in the long
haul. It may look and feel great for a year or two or three but
eventually water will find a way in.
Poke some holes through the inner wall of the block where its wettest
near floor level, masonry bit and hammer drill are easiest. Concrete
blocks usually have two equally spaced cast ribs inside so the trick is
to drill into empty pockets where water can gather and eventually seep
through the wall. More than one hole will most likely be needed because
many times there is mortar in the pocket. If water runs out then you
will need to either dig and seal the outside of the block foundation
(possibly *very* expensive) or install an interior french drain running
to a sump pump; not cheap either but depending on how the foundation is
built, exposed or buried, possibly a less expensive alternative.
If you can't get any water run to run out then its likely the typical
humidity problem inherent to basements and a dehumidifier may very well
cure your problem.
By the way, the holes are easily fixed with hydraulic cement. Fill as
much of the pocket as you can (think pastry bag, they actually make them
for cement ;) ) and next day go over it and smooth the surface.
Even if you intend to build a wall over the problem area and finish the
basement the water and/or humidity must be dealt with or it will always
smell and feel just like what it is ... a damp basement.
The best, and only truly effective way to make a concrete block wall
dry is to keep the water away from the outside..
First thing is to address grading and gutters to keep the water from
settling at the foundation. If that's all good,you need to be sure the
perimeter drains are intact and open. That usually involves digging
around the foundation - at which time a good membrane and
drain-channel system should be installed as well as repairing the
perimeter drain - ised to be clay tile - now filtered perforated
plastic flexible drain is used..
An inside solution will be limited in effectiveness and temporary at
best - and usually cost as much as doing it right in the first place
unless you need to tear up the basement floor anyway.
On Jan 15, 3:57 pm, email@example.com wrote:
been there done all this.......
did the outdoor job, cost 8 grand plus my time as laborer. took all
had backhoe dig to footer, waterproof walls, installed exterior french
drain, 18 tons of gravel, new downspout drains, new steps and
sidewalks, had excess dirt hauled away, regrade entire yard, all new
lawn. gave home curb appeal.........
5 months later water came up thru basement floor.:(
for 3500 bucks had interior french drain installed with sump pump.
lifetime dry basement transerable warranty
this fixed the problem
On Sun, 15 Jan 2012 07:18:01 -0500 (EST), firstname.lastname@example.org (Graven Water)
This will get as much conversation going as a thread on the
lubrication properties of WD-40.
1. Run from that contractor on anything to do with basements.
2. Find out *why* that wall is damp.
3. Fix it from the outside. [gutters, drains, landscaping-- maybe one
thing, maybe all]
After you cure the wet wall- wait a couple of years to be sure it
really *is* dry-- then cover it up.
sure-- once you figure out what you need to do to keep the water away
from your wall.
Chances are you'll need shovels & gloves. But you don't know what
you need until you know what the job is.
First get the water away from the wall. If it was mine, and the
wall hasn't been parged *on the outside* - I'd dig down to the
footers, parge [and insulate in my part of the world] and then
waterproof *on the outside*. Then backfill with the proper
materials and drainage.
I couldn't post this for a long time because my account was
I have heard, many times, the opinion that one should correct
the basic cause of any water coming into one's basement, and do
it from outside if possible. I do have a sense of the truth
and limitations of that opinion.
I've had many experiences with people online telling me things,
with total assurance, and being totally wrong. Sometimes
hilariously so, sometimes disastrously (there's a very funny
story I've told about one experience, in alt.home.repair, along
those lines). So now I take such opinions, not only with a grain
of salt, but salty like bar-snacks! There is no substitute
for actually being there, which is why I wasn't asking
this newsgroup whether I should pay for some major waterproofing
project on the outside of my house.
I was just asking some questions about what the estimator
proposed to do.
The estimator said his parging compound - whatever it is - would
work better than something like Drylok, because it's thicker.
That, I'm skeptical about, because one thing he told me was
that the (very thin) paint that's on the concrete block now,
wouldn't have to be removed to apply the parging compound.
For Drylok, they want you to remove any existing paint, so
it can soak in and make a water-impermeable layer. So Drylok
may be actually doing more than this parging compound.
I do know why the dampness is appearing. There used to be a
gutter in that damp area, that leaked a lot. The rest of the
wall doesn't have any visible dampness. I got the gutter fixed
about 10 years ago. According to the estimator who looked
at the situation, the wall would probably have had tar applied
on the outside. Probably the tar waterproofing was damaged
by the leaking gutter.
HOWEVER, I'm very dubious that even if I do something only on
the inside and it failed, that it would cause any real harm.
I'm planning to rebuild the wall inside with materials that
can't rot or feed mold. Any mildew that happened inside the
wall would be minor without significant organic material
there to feed it - judging by what I encountered when I took
the old wall off. Even if I did nothing at all to keep out
On Sun, 22 Jan 2012 15:54:25 -0500 (EST), email@example.com (Graven Water)
A crack can be fixed - even from inside - but water coming in through
a porous cement block wall will come into the block wall - even if it
doesn't get into the living area - and cause more damage. If the block
is saturated and freezes, severe damage will occur.
Adding an insulated wall inside, preventing the heat from inside from
reaching the block wall increases the chances of it freezing if you
are in an area where freezing is a possibility - and a freeze-damaged
block wall is not a pretty sight - OR cheap or simple to repair. You
really need to address the leak from the outside. Best way is to dig
down beside the foundation and waterproof it from outside - but at the
very minimum, make sure the ground is graded to keep the water from
pooling at the foundation. Even removing topsoil to about 2 feet
depth, packing clay as a run-off, laying a layer of heavy poly lapped
up against the wall, then laying a layer of crushed stone, topped by
landscape cloth and a layer of topsoil - the whole idea to divert
surface water and slow down penetration near the foundation, can be a
simple and very effective remedy. You want about 1 to 2" per foot
minimum slope, for about 3 or 4 feet out from the foundation on the
clay base, and at least 1" per foot slope away from the house at final
grade - and make sure the gutters work.
On Jan 22, 8:36 pm, firstname.lastname@example.org wrote:
one thing you DONT DO is finish the wall and worry about it later.
ideally its fixed from outside, but interior french drain will do.
they have a plastic membrame that will cover the wall and direct any
water into the french drain.
its impossible to seal water out of a basement, all you can do is
The OP appears to be planning on finishing the wall and worry about it
thats a bad idea mold can grow behind your new wall, a nice sealed
space, but the mold spores can still make you ill.......
first fix the wet wall properly, then parge it if you want.
best to wait awhile after fixing it to make certain your fix worked
before putting up a wall.
thats like remodeling the interior of a home that has a leaky roof
that needs replaced. a grand waste of effort
Sorry - I need to dissagree.
It is NOT impossible to seal water out of a basement. In areas where
frost is a problem, water IN the block wall can cause damage - and
sealing the inside, or using an inside drain, does NOT keep the water
out of the concrete block wall, and does not prevent the frost damage
On Jan 23, 1:34 pm, email@example.com wrote:
interior french drains at least around here have a hole at the very
bottom of each block cavaity to drain any water that collects to the
sump pump underground collector. thru some corrugated plastic
this makes it impossible for water to collect inside blocks and thus
the blocks cant burst from freezing.
outside drains arent necessarily successful, and difficult.
mature trees, patios, steps, AC units, sidewalks and all the rest may
be in the way.
and unless your outside drain is below the footer level water can
still come up thru the floor....
If you build in a swamp or other area with high water table and poor
drainage, yes. Perimeter drains HAVE to be below the footing to be
effective. Personally I won't buy a house that needs a sump pump.
And just because you drain the bottom of the hollow block wall does
NOT mean moisture in the porous outer section of the block wall can't
/ won't freeze - damaging the foundation. Only keeping water OUT of
the wall can do that.
Good drainage is paramount. Water sealing is secondary.But outside is
ALWAYS better than inside if it is possible.
Well after spending 8 grand and being the laborer on my moms house and
failing to fix the water problem the outdoor way, then spening 3500
bucks watching others work for less than a day to totally end the
water problem by opinions are well grounded in reality.
around pittsburgh many communities code requires a interior french
drain and sump pump system to prevent future wet basement complaint
when the home is built
in any case parging, drylock paint etc may look nice but cant really
keep a wet basement dry.
I believe the OP wouldnt or will refuse to believe this and waste his
time building a wall that will be ruined........
but its his back and his money........
I have personally seen properly applied dylock paint bubble. that is
develop water filled bubbles over a foot in diameter, when touched
On Jan 22, 3:54 pm, firstname.lastname@example.org (Graven Water) wrote:
So, after all this time, we finally have the reason why you've been
asking about metal and or vinyl stud material.
In your other thread "screwing into aluminum channel" you were asked
nurmerous times why you didn't want to use wood and, while many of us
suspected that water was the reason, you continuously ignored our
requests for a reason.
I still wonder why that was...
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