Still Too Much Moisture in Concrete Floor Poured in mid-April 2014

riaganach

Hi,

I recently renovated an old terraced house (built c1900). I used a builder
as I didn't have time nor the expertise to do it myself.

We took the floor up because there was no existing damp-proof layer
in the existing concrete floor.

The new floor was poured in mid-April and, according to our floor guy,
is still not dry enough to put down self-leveling compound.

We want to put down rubber backed floor tiles which need self-leveling compound.

The floor guy tested the moisture in early July and suggested giving it another couple of weeks. He said floors are usually OK after approximately 10 weeks.
He tested it again last Friday and there's still too much moisture to lay a new floor.

He suggested that there's a new (slightly more expensive) self-leveling compound on the market that is good for "damper" floors. He tells me that it seals them, allowing the flooring to be put down.

My inclination is to leave it dry out more - until the New Year.

So, I have two questions:

1. Is there anything I can do to accelerate the moisture reduction? (e.g. heating or dehumidifiers?)

2. Should I leave the floor guy use the new product or should I wait and see how it is after Christmas.

Any advice appreciated.

Thanks

Drift

I don't know anything about the rubber backed tiles you mention but it sounds similar to issues that occur when trying to lay marmoleum or equivalent linoleum style finishes on newly poured floors.

On a few fast track projects we've previously done the contractor has had to use a sealing compound on the floor because the moisture levels were too high for the standard laying process / levelling compound. As far as I know there have been no issues with these floors in the few years since they were installed.

Having said that my gut feeling would always be to allow the floor to reach an equilibrium moisture content prior to installation of the floors. Have you the heat on?

riaganach

Hi Drift,

Thanks a lot for the input.

You're right - the rubber backed tiles are kind of like a very heavy lino tile, to my untrained eye.
The heat hasn't been on as yet.

I agree with your "gut feeling would always be to allow the floor to reach an equilibrium moisture content prior to installation of the floors".

The moisture meter that I saw the floor guy use in July had a line of leds, with three colours - red, yellow and green.
The moisture reported was constantly in the "lower red" region. The floor guy said that there's no point using compound
or laying floors with such high levels of moisture. He would only consider laying floors when the moisture was in the "yellow" zone.

Thanks again for the advice.

Drift

I'm afraid it's beyond my area of expertise when it comes to what is allowed at what moisture contents. And even if it was something I knew about I would follow the manufacturer's guidance to the letter (or number) because that's the only way your product will be guaranteed!

Careful introduction of heat combined with good ventilation will help the drying out process for the whole house but it needs to be done very slow and judged carefully especially in such an old house.