Hardiebacker under Insulation boards?

[Old Mod]

Yeah all fair enough.
One thing to know about SLC it’s NOT self levelling.
Not completely anyway, it does need some help.
Buy a reputable brand, ie Isomat, Mapei, Tilemaster.
Follow instructions carefully.
It’s not a cheap product, so don’t buy Cheap.
Put a few markers down that show you the low points and work to a level set by your markers.
You can use screws in to floor or silicone joiners packers down to mark your levels.
That’s a very basic outline of how to get a reasonable result.

 

[Steve_Bcs]

thanks 3_fall.

 

[Dumbo]

To get a good finish a spiked roller is really usefull

 

[Steve_Bcs]

spiked roller to remove air I presume? would that still be ok to use over an electric under floor heating mat though?

 

[Dumbo]

I use a plastic spiked roller over underfloor heating and have never had a problem . Not only does it remove air it helps the slc run so helps remove trowel lines and also where you pour slc next to slc you've just laid . Don't get one with 10mm spikes they are not worth bothering with . As much as it pains me to say topps tiles don't do a bad one .

 

[Steve_Bcs]

Thanks. I think I am on the right track now

 

[Steve_Bcs]

Just completed my first ever ufh install & slc placement. I got the spiked roller from Topps too. I did forget to secure the joiners’ packers as my levelling guide - discovered they float! Anyway the floor was fairly level to start with and the Slc just covers the ufh wiring.

I’ll check the level again in the morning. If, it turns out its not quite level what would be the best remedy? Also, do I need to apply any primer before tiling onto slc?

 

[Qwerty]

Just use a small amount of slc to make good. Scraping or sanding high spots can be risky!

Yes, prime the slc before tiling.

 

[GoneGuy]

As @Plan Tec Tiling said, and prime with a sbr

 

[Steve_Bcs]

Thanks guys.
SBR? Is that a particular brand of primer? Can i use the same before tiling?