25 sq/m external garage floor - no expansion joints

[stuey72]

Hello all,

Can any experts give me some advice please. I have a single brick detached garage which I'm going to tile out with porcelain floor tiles ( 200x200 casalgrande padana granitogres technic 11.3mm thick).

The garage floor was a complete mess as the previous owner decided a tamped finish was good enough. I've spent the best part of 8 hours and its now ground down with a maximum depression in the concrete of 4mm.

The plan is to give it a couple of coats of BAL APD primer then level it with Mapei Ultraplan renovation screed. The adhesive is Mapei Adesilex P9 which came as a job lot with the tiles. In hindsight it would have been far easier to use an adhesive that allowed a thicker bed but I didn't expect the floor to grind down as well and I was given the P9 adhesive for practically nothing.

My concern is that there are no horizontal expansion joints anywhere on the garage floor. The floor measures 7.0m x 3.5m.

We know for a fact that the floor has been down just over 30 years. There are some hairline cracks which have always been there and i've always thought that this must have occurred during settlement early on.
To give you an idea of size, the allen key in the picture is a 2mm one:

The only gap is along the length of the garage on both sides, where the floor meets the founds:

The garage itself is baltic in the winter however its fairly cool in there in the height of british summer ( hah!) so I can only assume it has a good amount of rebar underneath the concrete and is thermally quite stable.

Can anyone please advise on how to move on. Is it fair to say that some small hairline cracks in 30 years means I shouldn't worry about cutting in expansion joints now?

Should I be treating the join between the floor and the founds as an expansion joint both for the SLC and the tiling?

Finally, i've bought Mapei ultra colour plus grout for the garage. Have I made an error and should have went with an epoxy grout instead?

Any help would be greatly appreciated.

Stu

 

[LM]

Hello Stu, for a few reasons I would advise levelling the floor and fitting Schluter Ditra 25 then tile. Your within the limits so need for an expansion joint in the tile bay. The Ditra will really help with the contraction and exspansion that will occur with this floor. I wouldn't be too concerned about the joints in the substrate that I can see from the pictures if you use Ditra. As it's a garage are you really concerned about the joints staining if not UCP grout would be fine.

 

[Italy]

personally, I have no problem to lay directly onto the substrate.
to the max, as collateral, put anti-fracture coating.
but lee, who know more than me.

I can see the color of the tiles?

 

[stuey72]

Hello Stu, for a few reasons I would advise levelling the floor and fitting Schluter Ditra 25 then tile. Your within the limits so need for an expansion joint in the tile bay. The Ditra will really help with the contraction and exspansion that will occur with this floor. I wouldn't be too concerned about the joints in the substrate that I can see from the pictures if you use Ditra. As it's a garage are you really concerned about the joints staining if not UCP grout would be fine.

Hi Lee,

Thanks for taking the time to reply.

Nearly fell on my ar$e when I seen the cost of the Ditra. I'm assuming that this is to act as a decoupler? Just read the datasheet and came across the following:

Note: If Schlüter®-DITRA 25 is only installed as an uncoupling membrane, side edges and ends of individual courses do not need to be sealed with Schlüter®-KERDI-KEBA. Please refer to the instructions for waterproofing if the membrane is to serve as a waterproofing layer.

So Lee, wondering if the edges need to be sealed or not?

Thanks

Stu

 

[stuey72]

personally, I have no problem to lay directly onto the substrate.
to the max, as collateral, put anti-fracture coating.
but lee, who know more than me.

I can see the color of the tiles?

Sure!

Colour is Dakota:

And non slip version:

 

[Concrete guy]

I'd just tile it with flexible frost proof adhesives, I wouldn't bother uncoupling. It's a garage not a Bentley showroom.

As it is a garage and won't exactly get toasty, allow longer for everything to dry than it says on the bag. Particularly the leveller.

 

[Italy]

Sure!

Colour is Dakota:

And non slip version:

ok, my concern in the garage, it is the color of the tile, light colors, porcelain unglazed, showing signs of the tires.
thanks

 

[LM]

With no cavity in the walls and probably no DPM in the floor there's gonna be a lot of moisture at play and the substrate isn't ideal so I'd advise to go belt and braces for all it's gonna cost in the grand scheme of things, but each to their own

 

[peteablard]

I'd be happy to tile it as it is. I use Weber which is suitable down to - 10

 

[Qwerty]

ok, my concern in the garage, it is the color of the tile, light colors, porcelain unglazed, showing signs of the tires.
thanks

In the UK we store rubbish, old bits of wood, broken lawnmowers, bikes. Very few people store cars in garages here......we like to protect our junk than our cars!!

 

[Time's Ran Out]

Done a few garage floors in very similar tile, usually direct fix or over panel of UFH to keep the Ferrari warm in winter. Extension joint around the edge.