SLC Top Tips Please

[Smudger]

Hi Top Tilers.

Tiling a floor tomorrow (brazilian slate) about 8 sq m. Floor too uneven to make good with addy as I go, but haven't used slc for a while (long while) and could do with a couple of top tips learnt from your combined years of experience and expertise!
It is a square utility room laid with concrete and has been painted some time previously (mostly worn now). Here is what I am intending.
Remove any loose/flaky paint with stiff brush, use laser level to identify/mark different levels, start in far corner and apply slc.
Why main questions are: What is best slc? WHat is the best consistency? Can I tile in same day? ARe there any special things to look out for/ be aware of.

 

[Diamond Pool Finishers]

use a spiked roller, to remove air-bubbles!!

 

[White Room]

Follow manufacturers instructions and mix as close as possible to where you will pouring

 

[Scott]

Make sure you have enough! Im not very good at SLC either and laid some over UFH on Friday night. Was bloomin awful when i went in yesterday and then had to add another bag as it hadnt covered enough and had left a high spot over the conduit for the probe. A second bag pours over the whole floor and pushed around did the trick.

 

[Diamond Pool Finishers]

i use Latexplan Trade from mapei, its a two-part self-levelling and smoothing compound!!, it for 1-10mm differences,
coverage is 6 m2 at 3mm thickness approx!! hope this helps smudger

 

[Alan.P]

I'm with Scottley, make more than enough so you have plenty, I tend to mark the dips using old off cuts stuck on top of each other to match up to the high spots, then you have a better idea of the level when pouring.

 

[kilty55]

i use fibreplan which to be honest is the closest slc that ive found that actually self levels,also tried webber rs slc recentyly and it was also very good

highlight your high points/dips and work to eliminate these witth a trowel,work as close to the room as possible and keep a bucket of water spare for cleaning your gear down as you go

baton any edges of rooms that have holes and also baton the door so it doesnt come into another room,Silicon the bottom of the batons to seal them in

 

[peckers]

I use ardex arditex na its a 2 part slc its not the cheapest but it does almost every thing! and its the best free flowing 2 part that i have found!
Make sure you have everything ready before you start.
fill any holes where it can escape.
across the doorway i always put down a piece of doorstop and seal with Silicon against the floor(this can be removed when slc is dry easily)
some manufacturers say to prime the floor others say to dampen with water(check on the bag) but if you prime with sbr then let it dry before you apply the slc dont put it down when its tacky as it seems to slow down the self levelling imo.
mix to a smooth lump free cosistency.
poor out the slc not all in one spot try to gauge it so as it flows and spreads itself over an area of about 3-4m2
Push it around with a steel float to the required thickness(I use a boat steel float)
then do your next mix and repat until fully covered.
make sure the edges of the place you just put the slc stays wet so as the next lot that goes down next to it can all run into each other nicely.(IE dont stop for a cuppa till your done)
some use a spiked roller i never have,

 

[DHTiling]

Mapei |NEW!!!! SLC Ultraplan renovation screeds... great stuff and flows like stella..🙂

Use a straight edge and try and figure your lowest points.. fill this and then work out at even depths.., IMO spiked rollers are for vinyl layers..🙂

 

[White Room]

Used spike rollers for 2 part resin paints on floors

 

[doug boardley]

if your slate is uncalibrated, I'd not bother with the slc Smudger.

 

[DHTiling]

if your slate is uncalibrated, I'd not bother with the slc Smudger.

Yep.. Uno back butteererrrrrrr

 

[Daz]

if your slate is uncalibrated, I'd not bother with the slc Smudger.

Just use a PTB adhesive like Mapei P4.

 

[peckers]

And if it is uncalibrated slate then allow for more addy!!

 

[Scott]

Push it around with a steel float to the required thickness(I use a boat steel float)
then do your next mix and repat until fully covered.
make sure the edges of the place you just put the slc stays wet so as the next lot that goes down next to it can all run into each other nicely.(IE dont stop for a cuppa till your done)
some use a spiked roller i never have,

How deep is your slc steve? 😱

 

[Smudger]

Yeah, Peckers. I wasn't planning on swimming in it (although by the time I've got it level I'll probably be able to touch the ceiling!):smilewinkgrin:

Great advice, thanks for all the input. Top site because its full of top people! Had a quick look at the slate when I went round and it all looks pretty uniform. The floor however, was covered in crap (looked like he had just been on "Cash in the Attic") so not sure how level, someone else had looked and suggested it would need slc, I'll see when the rooms empty and I can get a level on it. Once again, thanks to everyone for the very sound advice.

 

[SandyFloor]

Clean your tools thoroughly asap especially a spiked roller. If you're mixing outside, get a tarpaulin for underneath to protect slabs or monoblock etc. When you carry a flexitub of mixed screed carry it as low as possible so if a handle breaks it doesn't spill over.

All things I have learnt to my cost :lol:

 

[Scott]

Sandy what SLC do you use for Karndean? Im really keen on the whole karndean/amtico stuff but not the slc!

 

[Smudger]

Got all the units out today and marked levels the depth goes to 20-25mm. Spoke to Mapei tech and they recommend Ultraplan Maxi so I think I'll go with that. Thanks again for all the support.

 

[SandyFloor]

Sandy what SLC do you use for Karndean? Im really keen on the whole karndean/amtico stuff but not the slc!

F.Ball Stopgap 300 for over concrete and 700 flexible. The difference is in the finish in that it's extremely smooth. Anything you want know just ask me.

F Ball - The First Choice for Flooring Professionals - Smoothing Underlayments

 

[Peter]

Spiked roller is a waste of money imo, more for resin paints, doesn't make it any flatter.

Used to find levelling quite difficult until I bought myself a feather edge. Been doing quite a bit of SLC work since I bought it and it's paid for itself within the first square metre. Spread out in the general working area with a flooring trowel then run the feather edge over it. Where I was usually using 5 bags, the feather ege spreads it far enough to cover in 3. You're basically running off the highest part of the floor as your level rather than setting levels above and beyond what's needed.

Some of my previous SLC attempts were like motocross tracks.

 

[chrisroe]

Spikey rollers do not level slc you need a comb 5mm teeth and 500mm wide it gives a good even bed of slc and then run through it witht the spikey roller to remove bubbles any deeper then you can use a pin leveller to get the rough levels correct and a thin slc coat to give the neat finish

tilers in theory dont need to to slc a floor to a smooth standard needed for Karndean / Amtico but if you do then your customers will see the quality of your initial work then any doubts they have will disappear as quick as the bubbles in the slc

F Ball stopgap is v good but i struggle to get it so i enjoy the Bal one which i cant think of the name of it
Utzin is the best i have used but v pricey

 

[SandyFloor]

I frequently slc for larger tile jobs even if the if floor isn't too bad. I find it much easier and quicker to level the tiles when fixing plus less addy is required later which compensates for the cost of the slc. Best to us a screed rake or pin leveller as mentioned above but they need a lttle practice to get a level floor.

 

[Diamond Pool Finishers]

i have never tried the straight edge, but will give it a go!! my screeding don't need SLC anyway ,but for renovation work its a godsend!!

 

[Smudger]

I'll add this on here but not sure anyone will see it. As the floor is so deep in places I'm umming & ahhing about how best to approach it. Should I section it of, perhaps into 4 sections and do each separately? I'm worried about the slc spreading out too thin and getting in a mess with it. The other option is that there is a ridge running across the centre of the room which is causing the deep areas. Would I perhaps be better to try to shave this area down with a grinder before levelling the room as this would save slc and make the job easier (the ridge is quite large though).:mad2:

 

[DHTiling]

If you think you can remove the ridge then do, this will save slc ... if not then you can slc the deeps parts first and follow up with a full floor covering to flatten off.

 

[Spud]

most tilers do the slc the night before the tiling job pour out the compound and have the tools washed up and packed away and drive home while the slc is still wet , come in the next morning and find ridges and trowel marks,there is a time window as the slc goes off where it is hard enough to take your weight to walk on and soft enough to scrape any high points or ridges off with a steel float, its usually about an 1 and 40 minutes to 2hrs from when its mixed i recommend that when levelling you give it enough time that you can get on it while its green and check it with your 2m straight edge and shave off any high points that may or maybe not there

 

[Smudger]

Thanks again for all the great advice. It really helped my confidence. Poured the slc today and it came out lovely, customer is really happy which is what I'm after, so happy days. Thanks for the support you guys!