Hi all,

I have a 95 yo basement with a decaying floor that wicks moisture into
anything you rest on it. I installed a sump pump which helped, but
didn't solve it. There may be an issue with a high water table or a
natural spring. The cement is aged and cracked, but basically sound.
A few spots heaved up for some reason (Continental drift contributing
to mountain building forces perhaps? g), and the entire floor has a
(coal?) cinder base under it. If I put a piece of plastic down in any
spot for more than a day, it gets quite moist underneath. Since my
workshop is there, the dampness is causing all my tools to rust.

The proper solution here is to hammer up the floor, remove the cinder
base, level the dirt, lay a smooth gravel bed, and have a truck back up
to the vent window while a 4-man crew spreads a new slab. The proper
solution is also a lot more expensive and time consuming than I can
currently manage. I would have to remove the old floor to maintain my
head clearance which is already a little tight, and the basement has no
direct access to my back yard.

The improper solution I came up with is to remove and patch the heaves,
and then use latex fortified thinset with cement fiber backer board
over the whole floor. I would close the seems it with fiber tape and
thinset, and pour a leveling compound over the entire mess. After the
proper curing time, a quick coat of epoxy paint to finish it off.
Instead of a 3" or 4" floor raise, I would be looking at a 1/2"
to 3/4" one. It also seams like this solution would be strong,
watertight, and look attractive.

Any reason why I shouldn't pursue it? IOW, Could someone please talk
me out of this? Also, does anyone have an alternative to the two
approaches mentioned above?

Many thanks in advance.

Check out these water control tiling systems

http://www.schluter.com/english/prod...section-f.html

Familiar to some is the Kerdi system but the Ditra system looks like it
might fit your needs. Call them to discuss which is best for your
situation.

Yours sounds like an appropriate application for these more advanced tile
substrates.


wrote in message
oups.com...
Hi all,

I have a 95 yo basement with a decaying floor that wicks moisture into
anything you rest on it. I installed a sump pump which helped, but
didn't solve it. There may be an issue with a high water table or a
natural spring. The cement is aged and cracked, but basically sound.
A few spots heaved up for some reason (Continental drift contributing
to mountain building forces perhaps? g), and the entire floor has a
(coal?) cinder base under it. If I put a piece of plastic down in any
spot for more than a day, it gets quite moist underneath. Since my
workshop is there, the dampness is causing all my tools to rust.

The proper solution here is to hammer up the floor, remove the cinder
base, level the dirt, lay a smooth gravel bed, and have a truck back up
to the vent window while a 4-man crew spreads a new slab. The proper
solution is also a lot more expensive and time consuming than I can
currently manage. I would have to remove the old floor to maintain my
head clearance which is already a little tight, and the basement has no
direct access to my back yard.

The improper solution I came up with is to remove and patch the heaves,
and then use latex fortified thinset with cement fiber backer board
over the whole floor. I would close the seems it with fiber tape and
thinset, and pour a leveling compound over the entire mess. After the
proper curing time, a quick coat of epoxy paint to finish it off.
Instead of a 3" or 4" floor raise, I would be looking at a 1/2"
to 3/4" one. It also seams like this solution would be strong,
watertight, and look attractive.

Any reason why I shouldn't pursue it? IOW, Could someone please talk
me out of this? Also, does anyone have an alternative to the two
approaches mentioned above?

Many thanks in advance.

Interesting, PipeDown, but that stuff looks a little advanced for me.
Also looks a little pricy. The nice thing about the backer board fix
is that they sell everything I need at the Home Depot.

On 21 Apr 2006 10:59:42 -0700, wrote:

Hi all,

I have a 95 yo basement with a decaying floor that wicks moisture into
anything you rest on it. I installed a sump pump which helped, but
didn't solve it. There may be an issue with a high water table or a
natural spring. The cement is aged and cracked, but basically sound.
A few spots heaved up for some reason (Continental drift contributing
to mountain building forces perhaps? g), and the entire floor has a
(coal?) cinder base under it. If I put a piece of plastic down in any
spot for more than a day, it gets quite moist underneath. Since my
workshop is there, the dampness is causing all my tools to rust.

The proper solution here is to hammer up the floor, remove the cinder
base, level the dirt, lay a smooth gravel bed, and have a truck back up
to the vent window while a 4-man crew spreads a new slab. The proper
solution is also a lot more expensive and time consuming than I can
currently manage. I would have to remove the old floor to maintain my
head clearance which is already a little tight, and the basement has no
direct access to my back yard.

The improper solution I came up with is to remove and patch the heaves,
and then use latex fortified thinset with cement fiber backer board
over the whole floor. I would close the seems it with fiber tape and
thinset, and pour a leveling compound over the entire mess. After the
proper curing time, a quick coat of epoxy paint to finish it off.
Instead of a 3" or 4" floor raise, I would be looking at a 1/2"
to 3/4" one. It also seams like this solution would be strong,
watertight, and look attractive.

Any reason why I shouldn't pursue it? IOW, Could someone please talk
me out of this? Also, does anyone have an alternative to the two
approaches mentioned above?

Many thanks in advance.

Depends how long you want the fix to last. If you've got
water working up through the floor, then either the
coating you put on the concrete will fail, or the
concrete itself will fail. It will probably work
for a while, though. If you're even considering
eventually doing a real fix, then I'd say just
run a pair of dehumidifiers down there constantly,

I believe because of the continued moisture problem,
the thinset would eventually release the cementboard
and you'd end up with a "floating floor". All the parts
of your solution are also sensitive to ground movement,
which would also make the cementboard shear, and
the leveling compound will release. Leveling compound
is meant for a completely stable floor, and in the tile
trade it is meant to be covered right away- not as a
finish coat.

As others have said, you need to deal with the moisture.
Containing the moisture, as you propose, is very risky
and opens up other problems such as effloresence (sp?)
where moisture under thinset, cementcoat or grout causes
salts to leach out of the cement. I've seen this happen many
times, _always_ in the presence of continued moisture such
as you have.

The simplest solution I can think of is to skim coat it with
a mix of 50% flexible thinset (the expensive stuff), and
50% clean sand. Your floor should be super clean before
doing it, and consider painting a latex "link" on your slab
before doing it. As you skim coat it, scratch the coating
real hard into your floor to get a good bond. When I skim
coat, I use a notched trowel to scratch the coating into the
floor, then a flat trowel to level it. It's like if you drop a
booger onto your pant leg, you can lift it off, but if you
smear it in........it sticks pretty good......

Oh and as has been mentioned, de-umidifiers work great.
We live in Florida and used one in a non-air conditioned
storage room we had, and it kept the room dry.

Have fun,

thetiler

Hi Tilier. Thanks for the thourough analysis.

Having a floating floor was my fear. The weakest part of it would be
the seams. After reading everyone's feedback, I'm guessing I would
have a beautiful finished floor for a year, and then a gridwork of
cracks running through them leaking moisture. Each year it would look
worse until it completely fell to pieces. I guess I'll back off.
Thanks for talking me out of it.

The sand / thinset solution is intriguing. Great analogy with the
booger. I swear I've never done that before, yet I know exactly what
you mean. Half of my intention is to solve the moisture problem, the
other half is to make it look nice and tidy. I'm pretty sure I could
strike a smooth clean surface with my pool trowel. Also, for the latex
"link", someone once told me that the throw-away latex paint that
sells for $2.00 / gallon works great for this as opposed to the $30 /
oz. sold by the good folks at Quickcrete. Any thoughts on this?

Thanks again,
Tom

Paint is a terribly hard thing to stick to with cement products. In my
experience
of tens of thousands of tiles removed with chisel hammers, paint will
release
thinset faster than anything, so in my experience, it acts the opposite
of a "link".

Real "link" is that blue gooey stuff that is made specifically to link
new cement
to an old cement floor. I don't think it's expensive, and you simply
brush a
coating on and let it get tacky before applying the new cement mix.

Another option would be to make your own polymer thinset by combining
latex additive (made to be added to thinset) with plain thinset. Use
this
same latex liquid as a link by brushing it on straight, then letting it
dry
before you skimcoat with the latex/thinset mix.

You need to be careful to never mix latex additive to thinset that is
already
latex modified in it's dry form. If you use liquid additive, use
plain
thinset (the cheap stuff).

thetiler

I put some leveling compound to fill a hole around a spot where a
shower drain pipe comes thru basement floor. I been used twice and is
currently unused and capped off.

its a moist area and i checked the leveling compound is detoriating.

doesnt matter to me when theres money its new sewer time and that area
is a goner

If you can't afford to do it right then you surely can't afford to do
it wrong and then do it over.