2in concrete cap?

[Bretny]

Has anyone successfully poured a 2in concrete cap with out major cracking? There would bo no vehicle traffic and not exposed to weather.

Basicly im getting alot of moisture intrusion through my basement slab and looking to stop it. No standing water, just damp spots that stay there for months even with a dehumidifier running. Grading around the house and gutters helped alot but now its time to try something else.

I should note that the slab is about 4-6in thick with tar paper under it thats falling appart. Its poured in sections about 4x8. The house is from 1930.

I poured a dirt floor basement about 5 years ago and still have the left over vapor barrier from that. That basement was so damp the floor joists started to rot. Its now bone dry. I installed a permiter drain to a sump pump in that one.

 

[pauls340]

My suggestion is to track down the Vapor Lock rep in your area. www.spggogreen.com , a 2" cap of Vapor Lock Enhanced Concrete will stop all moisture vapor emission thru that "new" concrete. Note: Mother Nature wins 100% of the time so the new top surface is only as good as the substrate. Good luck.

 

[larry4406]

Only experience I had was where our concrete contractor had to cap a garage structural slab which was poured at the wrong elevation (inches too low). They cleaned the slab, applied a bonding agent, then did an over pour with a special mix concrete (sorry I don't recall details, 15+ years ago). Floor did not crack during the 3+ years I was still building in the community, I do not know the long term performance.

Good luck!

 

[Bretny]

That vapor lock is a prety attractive alternative if i didnt alreaty have the plastic heavy mil vapor barrier.
The floor now isnt cracked its just getting moisture from having no vapor barrier. If it does crack it really dosnt bother me. Im not rolling anything over this floor just walking on it. The cap would basicly be there to protect the vapor barrier from holes.

 

[850xpeps]

Do you have a drain and sump set up in this place? I would make sure you have proper water drainage if it means cutting a wheeping tile or drainage tile and then a sump, that’s what I would do. Then fill the trench in and cap with more cement. Then seal it. The tar paper, while not the best, should keep some moisture from slab. My basement slab was poured in 78 by whoever and has no paper or barrier under it. I get no moisture but I put a sump in with proper drainage.

 

[Bretny]

Yes i installed a sump pit. My plan is to not put the 2in cap about 2in from the wall. Leaving a 2in gap for the water to get around to the sump pit.
Tar paper is no good. To many seams and not water proof for very long. I have 10ft or 20ft wide proper vapor barrier made for the task with 3in wide sealing tape.

The only time i saw water in my sump put in 5yrs i drilled some holes in the concrete of the pit and got water out of them. I think that helped keep the slab a little dry not not enough.

Also in another basement on the property is the well casing. The water table gets so high i use to get water coming out of the casing. That basement has a drain tile around the permiter with a sump pump and is bone dry. The pump does run every few months.