Extension flooring

[IE00]

Hi we have had the following specifications for our extension (kitchen and dining), picture attached.

We are put off by the drying time for the 63mm screed, which our builder said would take 100 days. We are having engineered wood flooring and no UFH. Could anyone advise please:

What's the quickest drying screed?
Or would you go with T&G chipboard? What would be the issue with T&G chipboard Vs screed?

Thanks in advance

 

[Deleted member 174758]

UK Screeds quote a drying rate of about 1mm/day for the first 40mm, then 0.5mm/day thereafter. By that calculation 63mm would take 40 + (23 x 2) days = 86 days. However, we are normally permitted to walk on them (light traffic) after about 48 hours and I've seen main contractors turn on the UF heating after a week or so of natural drying and bring in dehumidifiers (or just use dehumidifiers if there is no UFH) to get the drying time down to 4 to 5 weeks. With that process the moisture content is regularly monitored with a Tramex floor moisture meter

Two or three layers of P5 t&g chipboard with an SLC on top would be a lot faster, but it will cost a lot more. Maybe consider 22mm P5 chip onto 40mm planed battens instead?

 

[IE00]

Thanks yes we were thinking of battens then T&G. How does this compare to screed?

 

[dazlight]

Just wait 30 days and put a liquid Dpm down they a smoothing compound any lay the floor

 

[IE00]

Has anyone actually waited the full drying time for screed? What's the reality for laying engineered wood flooring on standard screed?

 

[Deleted member 174758]

For solid wood flooring we always insist on doing a moisture level check with something like a Tramex meter before installing the flooring. It saves having to rip it all out and replace it when it swells and lifts, which it can do if the screed is too damp. If you insist on trying to cut the drying time without installing a DPM layer you really do need to check the core moisture content of your floor before going ahead to ensure they are within the manufacturer's specification. Unfortunately this cannot be done with low cost DIY meters which are as likely to give you a false reading as a good one. If you lay it on a wet floor you will have no come back on the manufacturer in the event of problems

Only once have I laid wood flooring on a floor which I hadn't checked for moisture and where there was no DPM. 3 months after it was installed we needed to rip out and replace over 60 square metres of flooring, fortunately not at our expense (pub/restaurant). Since then I have refused point blank to install timber flooring unless some form of moisture check is done or control (DPM) is installed. That's the reality of playIng Russian roulette with screed moisture levels

 

[IE00]

Thank you @JobAndKnock . Does it need to be a liquid DPM on top? What DPM would you recommend to install before laying the flooring? If I install a DPM, how long do I need to wait to install the flooring / what should the moisture content be?

 

[Deleted member 174758]

What recommendations do the manufacturers of your flooring make?

As an indication, with the solid oak wood flooring I've done (in the commercial sector) the residual moisture content within the screed has to be between about 0.3% CM and 0.5% CM when measured with a Tramex. This is our manufacturer's specification - yours may well be different. That's pretty dry but we rarely see it. We generally have to resort to laying two or three coats of an epoxy resin DPM on top, but even that won't work if the screed is too wet to start with. It's also relatively expensive and each coat takes about 24 hours to cure