drying out fresh screed... - TilersForums.co.uk | Tile Forums

Grace'sDad · 14-05-2008

My customer is having piped UFH installed in a couple of weeks into a new conservatory (20sqm). Assuming that it's going to be approx 60mm screed, am I right to say 1 day per mm for drying???

She is impatient and doesn't want to wait so what can be done to speed up the drying? Dehumidifier with heater???

Does anyone have reference to the "official" best practise where this is concerned?

The floor will be 600x400 travertine (with Ditra). Roof is already on.

Thanks in advance!

**wetdec** · 14-05-2008

Hi dad

leave it dry a while, soon as your adhesive can be used overlay it with Durabase CI HERE (same as Ditra).

25m2 roll of Durabase CI from us is £ 185.00 delivered with your discount

tiler

..

**grumpygrouter** · 14-05-2008

Hi 'Dad, not sure about Wetdecs Durabase but with Ditra, you can lay it and tile as soon as the screed is hard enough to walk on!

Grace'sDad · 14-05-2008

'You sure about that Grumps?

I thought there had to be less than 5% water content for Ditra.
Where does the moisture go if you seal the top with Ditra???

**grumpygrouter** · 14-05-2008

Quote:

Originally Posted by Grace'sDad

'You sure about that Grumps?

I thought there had to be less than 5% water content for Ditra.
Where does the moisture go if you seal the top with Ditra???

Positive 'Dad, have a look at this pdf attached in a different post -

Expansion Joints

**wetdec** · 14-05-2008

You are both missing the point here arnt you ?

As I said "as soon as your adhesive can be used "It has little to do with the mat you use its about the adhesive you use.

Both Ditra and Durabase are fixed with adhesive and can go down exactly the same time

tiler

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**grumpygrouter** · 14-05-2008

Quote:

Originally Posted by wetdec

You are both missing the point here arnt you ?

As I said "as soon as your adhesive can be used "It has little to do with the mat you use its about the adhesive you use.

Both Ditra and Durabase are fixed with adhesive and can go down exactly the same time

tiler

..

Not really sure what you are trying to get at here Tiler, are you talking about the adhesive not sticking because of the moisture or shrinkage of the slab?

**wetdec** · 14-05-2008

Quote:

Originally Posted by grumpygrouter

Not really sure what you are trying to get at here Tiler, are you talking about the adhesive not sticking because of the moisture or shrinkage of the slab?

I am saying the mat can be laid whenever you will be governed by what the adhesive manufacturer says about how soon the adhesive can be used on the green screed

You get me ??

tiler

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**grumpygrouter** · 14-05-2008

I know what you are saying regarding manufacturers guidlines, I was just wondering if they say leave new screed for 6 weeks to give time for the slab to shrink or if it is because the moisture content would upset the adhesive curing.

I suspect that it has more to do with slab shrinkage than anything else and that is the reason Ditra, and I assume Durabase, say to use their mats, to isolate the tiling from the slab shrinkage. As most adhesives are water based anyway I don't think it has much to do with it effecting adhesion.

**guy1976** · 14-05-2008

i would use the ditra and bal green screed ady

**wetdec** · 15-05-2008

There you go then either Durabase Ci or Schluter Ditra matting with Bal green adhesive.

The Bal green screed data sheet is here for you to check out m8

http://www.wetdecs.co.uk/images/deta...d_Adhesive.pdf

tiler

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**Dave** · 15-05-2008

You can use any type of rapid-set or flexible depending on what the room is and type of concrete substrate.... i.e. wet heating / conservatory etc........the matting will bond no probs and any moisture will just evaporate in the Ditra channels......
A new screed will need about 5 days so you can walk on it and leave no footprints etc , then you can overlay with Ditra and tile.....