Hi all
We had an extension done recently. Underfloor heating went in. Screed appeared level. Builders went on to tile the floor a week or so later. The underfloor heating was gradually turned up, and then turned down as advised.
A few weeks in, a couple of tiles cracked with just footfall. These were replaced. Then the tile edges started lifting very slightly. Now the grout all over the floor are cracked and coming loose. Tiles were 120x60 cm porcelain tiles. Method used for tiling was adhesive under the whole tile, then fixed using the tile levelling wedges and plier system. Uncoupling mat was not used, although supplied. Builder gave some reason.
Any thoughts as to why these are happening please? And how to rectify?
Are there special grouts for underfloor heating?
Many thanks
Biju
Are you a tradesperson and able to answer this question?
It may be that the tiles were not given enough room to expand around the edges of the room. Building standards say there should be a 10 mm gap around the edges to allow for expansion.
Thanks Max
The screed needs to cure for a minimum 6weeks before any tiling can be laid.also turn up heating by 3degrees a day to reach maximum.as for a solution I would take it all up and start again,also leaving a 10mm expansion joint around perimeter to allow for expansion and contraction
Answered3 November 2022
1
Anonymous user
Should of gave the screed more time to fully cure before tilling any moisture left will push up and unstick the tile adhesive causing cracks and movement
Normally it takes a couple of weeks to gradually introduce heat [Under floor heating]. I normally advise my customers to turn it on for 30 mins a day and each day turn it up .5 of a degree until you eventually get to your desired setting [This could take 3 weeks].
Also, the screed/self leveller should of fully cured before tiling. A moisture/damp test would have confirmed that.
Hi , first off all if is a traditional screed needs 90 days to cure before putting any tiles on it , if is a fast dry screed you can tile after 7 days. The questions is ?did anyone measured the moisture from the screed before tiling . If the moisture in the screed is below 5% is ok for tiling and you don't have any problem if is more then 5% I wouldn't tile on that screed unless the client is happy to spend a little more money to apply a special primer as Norcros Pro Gyp-Base Fast Track Sealer to help the adhesive making a good grip to the screed and tile. Also using those self levelling clips you need to make sure there is a 100% full bed off adhesive under the tiles .
There are so many steps to do when comes to tiling , good preparation off the surface, back buttering the tiles etc .
