Warmup Insulation Board over Hardiebacker???

[jond500]

Hi All,

The bathroom is still coming along and despite loads of life issues slowing it down it's going well.

I discovered that installing 10mm Warmup insulations board would make my life easier in terms of installing the probe as opposed to digging through the already installed 6mm Hardi that was installed as per the advice here previously.

The Hardi is completely flat and no deflection.

I tried asking Warmup what notch size they would recommend but they wouldn't commit 🙁 Bearing in mind the floor is already solid, straight and level would 8mm be OK?

I will be using rapid set flexible addy and will be using the same to tile the floor once the UFH is in and the SLC applied.

Does the above sound OK?

Cheers,

Jon.

 

[Qwerty]

6mm usually suffices jon. Why is hardiebacker down and then insulation boards?

 

[jond500]

Hi,

The Hardi was already down as originally I was just going to tile the floor but then decided to go for UFH. It's only 1.5m SQ so it wasn't an issue cost wise to add the insulation board. In fact the main reason for using it is it will make sinking the thermometer probe much easier rather than trying to cut a channel into the Hardi.

Cheers,

Jon.

 

[Rookery]

You need to choose a trowel relative to the tile size and flatness of the floor. Generally I'd be looking at a 10mm notch and back skimming the tile too. Assuming the tiles arent mosaics!

 

[Qwerty]

You need to choose a trowel relative to the tile size and flatness of the floor. Generally I'd be looking at a 10mm notch and back skimming the tile too. Assuming the tiles arent mosaics!

10mm is a hell of a lot of adhesive for fixing down insulation boards! Perfect for the tiles agreed, but I read the question as asking what trowel for fixing the boards down.

 

[jond500]

Thanks Geoff, you read the question correctly.

Rookery, I will be using a 10mm notch for the tiles themselves and be back buttering.

I only have a 3mm for the wall mosaics and an 8mm for the wall tiles. I don't have any others but if I need a 6mm for the Insulation board i'll get one, albeit a cheap one as I don't forsee doing any more tiling for a good while until the next DIY project.

Cheers,

Jon.