Timber Floor over slab?

[VinoTinto]

has anyone had probs with adequate circulation with timber floor/batten/concrete slab configuration? My builder is raising concerns re timber stability for my 6 sq slab addition. Obviously lots of moisture in the slab and minimal airflow under boards.
Comments?
Thanks in advance
Vino

[arms]

there should be no problems as long a a layer of viscreen of similar moisture barrier is layed to manufacturers spec over the slab and between the boards

kind regards
tom armstrong
www.armstrongcabinets.com.au

[Gaza]

A membrane is only required when the slab is a slab on ground or the moisture content of the concrete is above 5.5%, as a general rule we always used plastic (200um) it only costs $50.00 per roll, make sure that you tape and over lap the joints.

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There is heaps of info on the TDA (timber development association) web page. At www.TDA.com.au

[glock40sw]

G'day.
If it were my T&G flooring production, I would say... Don't lay it!!!!
Find out why the slab is wet. Fix this!!!! then lay the timber.
If It was my flooring and I got called to inspect a problem with the flooring once it was laid. I'd be after the installer's blood for laying it over a wet slab.
It doesn't matter if a membrane was installed or not.
YOU DO NOT LAY TIMBER OVER A WET SLAB....FULLSTOP.

Hooroo.
Regards, Trevor
Grafton

[Peter36]

Timber floors are being laid on new slabs all the time and as Arms says ,if you properly install a moisture barrier - no problemos . I would suggest laying parquetry as this can be competitive with strip floor , particularly on a slab and saves having to batten .

Peter

[glock40sw]

Parquetry will still suffer from a wet slab.
I have seen Ultraset and Regubond adhesives fail due to too high moisture in a slab causing the blocks to expand.
As a rules of thumb....If the slab is wet...DON'T.

Hooroo.
Regards, Trevor
Grafton

[Peter36]

G'day Trevor , Iv'e always used epoxy when fixing parquetry to a slab as this provides the barrier as well as the adhesive . The only problems I have had have been when water has been left to sit on the floor - read the plumber had a leak - but even then the blocks stayed intact and did not lift even though the pressure between blocks raised a ridge between them . Clients just wo'nt wait long enough for a slab to dry out .


Peter

[alexeib]

Having just installed parquetry on a slab in my house -- you still apply moisture barier. Both of major floor glue manufacturers (Bostik and Sika) have glue and moisture barier epoxy that are meant to compliment each other. Both offer 10 year warranty if it is used to their spec. (Who is going to certify that?)
Bostik, in their spec for the Moisture Seal, say that it can be applied to the green slab.

Glue itself usually does not serve as a moisture barier. I know there are some new glues that claim to do so, but as you use notched throwler to apply it you are inevitably left with some gaps, so the completness of such a barier is questionable.

Still it would be unwise to install floor covering on a slab that has, say, leaking pipe in it, so if your slab is wet due to other reasons, becides been new, it should be corrected first.

Just what I learned in prep for my install.

Regards,
Alexei

[Gaza]

Timber floors & Moisture don't mix, if the slab is always wet then the floor will cup up and bow.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>

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The Timber flooring that is supplied by good manufactures is dried out to MC of between 10-15%.<o></o>

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When the timber is exposed to any moisture for a period of time it will "suck" in the moisture and the boards will expand thus cupping. (That is why expansion gaps are need under skirting and at junctions with vertical surfaces.<o></o>

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The moisture seal products made by the glue manufactures (skia, bostic etc) are the slimar to the ones used in bathrooms to stop the moisture getting out this case they are used to stop it getting in. (NB use same manufactures products or good bye warranty) Even these have a limit to there effectiveness.<o></o>

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Parquetry requires even perfect conditions for installation ie, levelness of slab, moisture content, acclimatization and effect of the floor finish applied.<o></o>

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I hope that I have supplied some information that can be used to assist in your practical project, I am just speaking from the expensive I have in installing timber floors but it is hard not being able to see the job.