How long to leave UFH screed to dry before tiling ?

E

ennisjim

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Hi,
Screed (concrete - 75mm) is in about 3 weeks now. I don't have UFH working yet so it's drying out at its own pace. I was hoping to do some tiling in next few weeks which will certainly be before the UFH is up and going (long waiting time for plumber). Does anyone know if it's OK to tile before UFH is working and if so how long would I need to leave the screed ?

This relates only to tiles. I will be using timber flooring also, but I'll be leaving that until UFH is working and storing flooring in house for X weeks to aclimatise.

Thanks
James
 
Hi James, we were told to wait a week/inch of slab in good weather (I believe this refers to air humidity!) before the floor dried out. Not sure how long to leave it in the current dampness!
 
ennisjim,
I'm sorry that I can't help you with your question, but I will watch with interest the replies you get as I will be in your position (hopefully) soon.

Are you putting the timber floor over the UFH? I want to do this also ( I am aware of the arguments against, but I'm going to do it anyway ). What type of wood are you going for?
Thanks.
 
what happens if when the ufh goes on that you have a leak?surely it would be easier to remedy this if you havent tiled the floor! i personally would wait for the plumber. has the line been pressure tested?
 
Hi Bluebells. Yes I am planning to use semi-solid timber flooring glued directly to floor. I have heard that since semi-solid is thinner than solid it is better with UFH and lets more heat through. Also since it is engineered (laminated in different directions) it is less prone to deforming with heat. At least that's what I'm hearing.
I have semi-solid maple in my existing house (not UFH) and it looks really good.
 
Hi seantheman. The UFH pipes are currently under 4bar pressure and have been for about a month so I would be very surprised if any leak problems arose when water is heated to the low temps that UFH use.

Would like to proceed with tiling because can't do a lot else while waiting for plumber. My current thinking (in the absence of any other advice) is to give the screed another couple of weeks and then start tiling. Timber will wait until UFH in action.
 
Safe than sorry and all that!! Timber moisture will have to be checked.
 
If there is lots of other work going on in the house, cover the tiles with cardboard once you have them in, as otherwise they can get badly scratched with workmens boots! (It also helps to keep the grout clean)
 
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I would say you should wait a bit longer to be honest. We had ours down about 3months before we lay the tiles.. Cracks, albeit small appeared when it was fully dry - about 2 months afterwards... and this was earlier in the year when we had drier weather. In fairness we put our screed in last october / november and only laid the first tiles tiles in late february.

We have tiles down in the kitchen and hall and all the bathrooms now with a couple of weeks and we only turned on the water this week (Mon) for the UFH.... One leak in the main ensuite - and nothing to report since thank god.. We too had to wait for the plumber..

With regards to floor boards we to are going for the semi solids - will do the moisture testing but they say that you should leave the heating on in the house for 2 weeks before you lay floors. AFAIK the same does not apply for tiles. (well at least I hope not). It is not advisable to use solids.

Agree 100% with the cardboard idea. Spent 5 days mopping, scrapping and cleaning on my knees my kitchen floor - even when I had cardboard and plastic down... Am getting a guy in to polish the hall floor once i have the carpentry done and then its no boots or shoes past the front door!!

I hope this helps and its great satisfaction getting to this stage.
 
ennisjim said:
Hi,
Screed (concrete - 75mm) is in about 3 weeks now. I don't have UFH working yet so it's drying out at its own pace. I was hoping to do some tiling in next few weeks which will certainly be before the UFH is up and going (long waiting time for plumber). Does anyone know if it's OK to tile before UFH is working and if so how long would I need to leave the screed ?

This relates only to tiles. I will be using timber flooring also, but I'll be leaving that until UFH is working and storing flooring in house for X weeks to aclimatise.

Thanks
James
Click to expand...

usually from 21 days to a month for the concrete to cure totally, and you could tile on b4 the heating is going. I should be safe now that it has been down so long
 
1 month per inch of screed. I've done this, and just checked my moisture in the screed with a proper meter before letting the tiler loose.........floor is bone dry -and it needs to be.

Have any expansion cracks (e.g. put in at doors, etc) appeared yet? If not, your floor is not ready.

Stuff is going to move once the system is up and running, believe me. I have screed over insulation over timber frame.
 
Hi polo1 and galwaytt, re. cracks there are some across the double door opening from living room to kitchen but apart from that nothing. From what you're saying it's likely there will be more so I think I'll leave it for another 3 or 4 weeks before tiling.
Guess I'll just have to find some other tasks to keep me gainfully employed. Internal plastering finishing tomorrow so looking forward to seeing it.
Thanks all for advice
 
ennisjm - iirc you looked at wet screed originally (so called "self levelling"), I gather you didn't do that....?

And, did you use that pump crowd I sent the name of, or barrow it in?
 
ennisjim said:
Hi polo1 and galwaytt, re. cracks there are some across the double door opening from living room to kitchen but apart from that nothing. From what you're saying it's likely there will be more so I think I'll leave it for another 3 or 4 weeks before tiling.
Guess I'll just have to find some other tasks to keep me gainfully employed. Internal plastering finishing tomorrow so looking forward to seeing it.
Thanks all for advice
Click to expand...

why don't you put some control cuts in your slab?
 
Hi galwaytt,

Went for standard concrete screed and not the self-levelling liquid screen. Reckon concrete was about €3K or €4K cheaper.

Also went with barrows and didn't bother with pump. Put down lots of OSB and other timber for barrows to run on. No pipe bursts or pressure loss thankfully.

Screeder cost €10/m.sq by the way for 210 m.sq bungalow. Pump would have added €80/hour.
 
Hi dble8. I have 2 control joints in long corridor walls so put same in floor at these points. Don't think I would be inclined to put control cuts at every door opening though. Also I guess cuts would only be able to go down a little over an inch for fear of cutting UFH pipe. The 2 cuts in the corridor are based on edge insulation embedded in screed.
 
hello, i am a carpenter and would not put tiles or flooring down until the floor is fully dried out. 1day per mm= 75 days. if you use a dehumidifier it will speed up the process. i wouldnt put down anything until ufh is up and running
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ennisjim said:
Hi dble8. I have 2 control joints in long corridor walls so put same in floor at these points. Don't think I would be inclined to put control cuts at every door opening though. Also I guess cuts would only be able to go down a little over an inch for fear of cutting UFH pipe. The 2 cuts in the corridor are based on edge insulation embedded in screed.
Click to expand...
concrete will tend to crack at every weak point ie where your direction changes or a break in the main line of your shuttering or if the area is over about 2 1/2-3meters in length.
of course you can't go too deep but if you put the cuts in then the concrete will move free in b'tween these and they only have to be about 10mm min to say15-18mm
but it will stop other cracks appearing. Hope that helps
 
You should put the heating on before tiling & turn it off so the tiler can work. There is less chance of the tiles cracking afterwards
 
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