Hello to you all again. Further to my previous threads on this, now the weather is normal, I decided to begin work my step. I Used SLC on the step but (maybe unsurprisingly) it iddn't level. I think the problem is I worked the compound too much trying to achieve a perfectly smooth finish. Obviously I'm no pro and dont exopect a pro's finish just a decent surface to tile to, any descrepancies a I can then make good with addy.

If I'm going to give it a secnd pour can you advise me on he following

1) Will i need to prime the surface first, ( i will probably do this anyway but will welcome any advice)

2) Once I have trowelled it to where I want it do i then leave it or do I need to work it to a perfectly flat and smooth finish, If so please advise if there are any partivular techniques.

3) The amount I need to make up is at the most5 - 7 mmwould I be able to forego the above and level it with a thicker mix of adhesive. ( Im only thinking this because I now know why people say it is tricky to work with SLC for the first time, but all part of the learning curve!)

I look forward to any advice you can give

Many thanks - Ernie

try and get your slc to level at about 3mm discrepency if you can,then you can make up the difference using a stiff mx of addy and a 10/12mm notched trowel,that should save you trying to hard in getting it level!

THanks Dave, I will do that. Out of Interest do I have to work it to get a perfect smooth and flat (not level) finish and is it best o pour a little, work it then add more?

cheers - Ernie

how thick is your slc? you shouldnt need to work it to much.

John

Which SLC did you use...?

I Used granfix thick bed levelling compound it can go to 50mm. I used about 10 - 12 mm thickness.

Ernie

Just asking ernie, coz not all levellers can be used outside..

Originally Posted by ern

Hello to you all again. Further to my previous threads on this, now the weather is normal, I decided to begin work my step. I Used SLC on the step but (maybe unsurprisingly) it iddn't level. I think the problem is I worked the compound too much trying to achieve a perfectly smooth finish. Obviously I'm no pro and dont exopect a pro's finish just a decent surface to tile to, any descrepancies a I can then make good with addy.

If I'm going to give it a secnd pour can you advise me on he following

1) Will i need to prime the surface first, ( i will probably do this anyway but will welcome any advice)

2) Once I have trowelled it to where I want it do i then leave it or do I need to work it to a perfectly flat and smooth finish, If so please advise if there are any partivular techniques.

3) The amount I need to make up is at the most5 - 7 mmwould I be able to forego the above and level it with a thicker mix of adhesive. ( Im only thinking this because I now know why people say it is tricky to work with SLC for the first time, but all part of the learning curve!)

I look forward to any advice you can give

Many thanks - Ernie

First off: Did you use exterior grade SLC, ie frost proof SLC? If you didn't, and it freezes, it can crack. Personally, I'd use something commonly called "repair mortar" (Ardex A46 for example) to fix up the step before tiling. Repair mortar is easier to use on steps than SLC, as it's stiffer, and it's harder and more resilient than adhesive once cured, so it's more suitable to tile onto. Use proper materials where proper materials are due

Second: Did you create a little slope, just a couple of mill or so, so that precipitation runs off? If you didn't, you'll have to do that when you fix the tiles. Excessively accumulated precipitation can cause waterlogging, which can weaken the substrate and the hold of the adhesive over time, especially if temperatures vary alot. It can also discolor grout.

Third: The need to prime really depends on what adhesive you use. Read on the bag, or the manufacturers website. Make sure to pick one which is frost proof.

My five cents.

Thanks SWe and Dave. I checked on the bag and also rang Granfix, both confirm it is suitable for exterior use.

I know this may be dumb but what do you exactly mean by precipitation. I didnt leave a fall because the step is covered and cannot get wet even during rainfall but I guess you mean something different.

Ernie

Thanks guys, the SLC can be used outside, the bag states it is ok for exterior use and I also could Granfix who confirmed this.

I know this may be dumb but what exactly do you mean by precipitation?


Ta Ernie

Swe means vapour / water residue.....

Hope the weather is OK or you may have to start again if SLC gets frost into it before curing