Quick Drying Screed......sounds too good to be true....is it?

[alybalybee]

Does anyone have any experience of quick drying screed they'd like to share?

We are planning to lay 100m sq. of screed at some point in the next month. We had planned to lay a traditional screed which dries, I believe, at a rate of 1mm/day, ours will be 50 - 55mm deep and we don't really have 50-ish days to wait for it to dry. Which brings me to modified cement screed which appears to dry at a rate of 3mm/day, this we can cope with. I've had quotes for both and the difference in price is negligible which makes me wonder why everyone doesn't use the quick drying screed, or, am I missing something and it is too good to be true?

Any words of wisdom would be greatly appreciated.

Many thanks.

I don't know. Is it a pre-mixed screed delivered from a readimix truck? Ask the supplier to tell you the Standard number so you can look it up, or the name of any proprietary additive.

It is possible to use less water in the mix if various additives are used, or maybe it has a high air or foam particle content.

What are you going to cover the screed with? Damp screeds are often covered with a DPM, as well as the one underneath, if they are being covered with a moisture-sensitive floor such as timber.

Cement-based products are harder and stronger if they are kept damp for a couple of weeks.

and the wetter/softer they are the better they are at levelling...

We have conventional screed 65mm thick in a very well ventilated (minus lots of doors and windows!) extension which they say should be dry next week (3 weeks from screeding). It would have been quicker if the screed had been directly onto insulation, rather than the insulation being under the subfloor. But it has been good drying weather here. Builder says he has heard bad things (tiles lifting) re quick drying screeds but this is only hearsay. He says the 1 day per mm would be more suited to winter weather / poor ventilation. My floor is currently covered with inverted glasses to see if any moisture condenses tonight to see when tiler can come. HTH.

Great responses, thank you. I think more investigation is required!
Honu, good luck with your screed!