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Seeping through cracks
- Thread starter padre1964
- Start date
Angelfire
Well-known member
Looks like efflorescence being carried upward by moisture. Basically salts migrating (calcium, etc...). Remove the water under your slab and this will stop. One way you can verify this is to do a moisture test. Tape clear plastic down on the floor and check it over the next few days for any moisture being trapped. If you have moisture coming up, you need to fix that before putting any coating down otherwise the coating will just lift off at some point.
Shea
Well-known member
Angelfire is right on the money about testing. It most likely is moisture vapor from below the slab.
One question though; does your slab sweat? It's not uncommon to experience sweating slabs in your area of the country. If so, it's possible that the condensation that your slab experiences allows moisture to collect down in the cracks. When the weather changes and allows that moisture to evaporate out of the cracks, then it can leave the mineral deposits behind as was stated. The only real way to tell is to do a moisture test.
One question though; does your slab sweat? It's not uncommon to experience sweating slabs in your area of the country. If so, it's possible that the condensation that your slab experiences allows moisture to collect down in the cracks. When the weather changes and allows that moisture to evaporate out of the cracks, then it can leave the mineral deposits behind as was stated. The only real way to tell is to do a moisture test.
Angelfire
Well-known member
Just looking at the photos again and see how the concrete is dark around the cracks? My guess is that's moisture causing the discoloration.
With regards to fixing it, I'm not all that sure until you can identify the source. If you have good drainage around the building to keep rain water from getting underneath, then you may be in a situation where it is just moisture coming up from the ground underneath. Do you know if the slab was poured over a vapor/moisture barrier?
Cheers.
With regards to fixing it, I'm not all that sure until you can identify the source. If you have good drainage around the building to keep rain water from getting underneath, then you may be in a situation where it is just moisture coming up from the ground underneath. Do you know if the slab was poured over a vapor/moisture barrier?
Cheers.
Garage Flooring
ALLIANCE MEMBER
Angelfire is right on the money about testing. It most likely is moisture vapor from below the slab.
One question though; does your slab sweat? It's not uncommon to experience sweating slabs in your area of the country. If so, it's possible that the condensation that your slab experiences allows moisture to collect down in the cracks. When the weather changes and allows that moisture to evaporate out of the cracks, then it can leave the mineral deposits behind as was stated. The only real way to tell is to do a moisture test.
This ^
Not properly addressed your coating will fail. Could become a very big project very quickly.
Slowgsr
Well-known member
Do you have a sump pump ?
Not on a sump pump. I don't believe i get sweating on the slab but i will keep an eye on it. No idea on how the slab was poured since i am not the original owner. I will try the barrier process and see what that reveals. Looks like my alternative will be tiles. Question is, will the efflorescence eventually seep up through the tiles ?
Thanks for all the help
Thanks for all the help
I have the same issue, but it is not coming from underneath the slab. Every time I pull the car in after raining it causes surface efflorescence, and it is worse anywhere the water pools such as joints and cracks (like the above image).
From what I've read, it sounds like I can acid etch, grind, and epoxy to prevent it, correct???
From what I've read, it sounds like I can acid etch, grind, and epoxy to prevent it, correct???
Shea
Well-known member
Just do a moisture test first to verify. If you grind, there is no need for acid etching. Once your coating of choice is down you will be good.
Given that you are already witnessing evidence of moisture I would skip straight to the Anhydrous Calcium Chloride Test. Along with the test kit, you'll need a 1/10th gram scale which, for whatever reason, are available super cheap everywhere nowadays...
Anhydrous Calcium Chloride test
Anhydrous Calcium Chloride test