2nd opinions on UFH tiling method please?

[SpunkyTheMonkey]

i'm after some 2nd opinions on what i've been told today.

we have a small flat in a building we're putting up which has (water) UFH, the biggest room is the living room, the screed is broken into 2 sections of ~2.5x2.5m with an expansion joint down the middle, plus expansion joints at all the doorways, the bedrooms are ~3x3m (1 section of screed). the expansion joints and edges all have 1cm foam underlay type stuff in them.

now, please bear in mind that builders/tilers here are a bit stuck in their ways and i *do not know* if anyone sells polymer addy or flexible grout etc, simply because none of the tilers here seem to use it.

our civil engineer says:

• 3mm spacers (yes three, he reckons it's fine for such small sections of screed)
• normal glue
• where a tile overlaps an expansion joint, say 2/3 on one side and 1/3 on the other, it should have addy on the 2/3 side, nothing directly over the joint, and Silicon (underneath the tile instead of addy) on the 1/3 side
• Silicon instead of grout over/around the expansion joints (obviously)

our tiler does very nice work but is a bit inexperienced and really doesn't know anything about how this should be done.

i'm going to try and source some polymer addy and grout but if nobody has it i'm just going to have to go with bog standard addy.

thoughts?

 

[DHTiling]

You might be able to get an additive for the adhesive and grout..

As for the method over the expansion joints... that is wrong.. you need a break in the tiling exactly over the expansion in the screed floor.

 

[SpunkyTheMonkey]

thanks, that's what i thought...i'm assuming that includes all the doorways too?

oh, one last question, if i'm getting him to use 3mm spacers for the tiles, the expansion joints should be 3mm too right? and 6-8mm around the edges??

 

[DHTiling]

Doorways too yes..

The expansion joints can be pre-formed or a cold( Silicon) joint.. and yes the cold joint is normally the same as the grout joint but in my opinion it should be 5mm minimum.. this extra 2mm will not really be that much noticeable.

 

[SpunkyTheMonkey]

awesome. thank you.

 

[merlecollins]

where a tile overlaps an expansion joint, say 2/3 on one side and 1/3 on the other, it should have addy on the 2/3 side, nothing directly over the joint, and Silicon (underneath the tile instead of addy) on the 1/3 side

:yikes::yikes:

You checked this fellas credentials?

As mentioned already, a movement joint is needed over the structural joint. Why not ty and set out youur floor tiling from the structural joint - that way the expansion will work on a full tile on at least one of them

 

[peckers]

IMO, you need to use a single part flexible adhesive for a screeded floor with wet underfloor heating and a flexible grout too! If you cant get it where you are(dont know why) then you can buy an additive to add to the adhesive and grout to make it flexible. You also defo nead to install expansion joints above the expansion joints already created in the floor edges and doorways! either as mentioned before by means of a pre fabricated one or by way of a cold Silicon joint. And the tiles need to be stuck down either side of the expansion joint with adhesive and not just left to float over the expansion joint in the screed!(This is wroung)

 

[SpunkyTheMonkey]

:yikes::yikes:

You checked this fellas credentials?

he's a civil engineer, not a tiler. for some reason my plumber thought this guy knew a bit about how to do the tiles for ufh. clearly he doesn't... :lol:

i can start from the biggest and most obvious joint, that's no problem, there are a couple of places where doing things in the most correct way might start to ugly things up a bit (long story) but we're going to explain to the lady who bought this flat how it *should* be and let her decide what corners to cut if any (on her own head of course).

 

[peckers]

Imo if you are offering the job to tile the floor either doing it yourself or by supplying a sub-contractor then it should be done right or not at all!! if you cut corners it will bite you in the rear end!
explain to the customer the right way of doing it and im sure she will know what you are suggesting is right and she will want a proper job done.

 

[SpunkyTheMonkey]

agree 100% but i'm mopping up the mess from when my father in law was *supposed* to be looking after this building site at the beginning. in this case that includes stupid **** like expansion joints where bookcases and sofas are going to go in order to save a few euros for the customer by not laying pipes where she doesn't need them...fine for now, fugly if/when she decides to rearrange the furniture.

i'm just going to tell her how it should be done. if she starts spitting her dummy because she doesn't like how it's going to look, only then will i possibly start entertaining the idea of her deciding to cut any corners.

now i know a bit more about this, and my dear father in law will not be allowed anywhere near any more of my building sites, it'll be planned much better in future... :incazzato:

 

[Ajax123]

It seems that everything that needed saying has been said apart from perhaps you should consider getting a civil engineer who knows what he is talking about.

That said it seems a pleasant change to hear that the screed has been installed exactly as it should have been.

Probably the only thinig I would have done differently is that instead of 10mm joints I would have formed 5mm for bays this small.

 

[SpunkyTheMonkey]

yeah, already got a new engineer for the next building who's actually really good

i'm taking over a construction company from my father in law who's been lurching from one knee-jerk reaction and disaster to another for about 30 years now, and still doesn't seem to have the slightest clue who's good at what or how anything should be done.

i'm getting there now, finding people who are good at their jobs...i have a couple more no-hopers to replace for the next building and my life should be a bit easier.