Idiot’s guide to self leveling compound

I’ve got a small (1.4m2) room to level before tiling. I’ve gone with manufacturers recommendations and it’s had 2 coats of Blackjack followed by one dilute SBR. But there are various dips and a slope, I think the largest drop is 35mm ISH.

Next step is a coat of neat SBR then deep fill self level. Have watched a load of vid so pretty sure I’ve got everything set up and a trowel to push to the edges. However, I’m aware that self leveling doesn’t actually totally self level, so what’s the best way to ensure it does? Packers at say, 4 points in the room to height measured with a level, then removed after the compound is down? Or a bit of timber at the far edge (it’s a rectangle, boxed in toilet at one end and doorway at the other) and then use a straight edge to level with that?

Or am I doing it all wrong?! The compound I’ll be using is Sika 245. All the chemicals and processes were given to me by Sika support.

Thanks!

Do you really need it to be properly level or just flat? If the latter I wouldn’t be too bothered about setting up packers to mark depth I’d just get pouring. On such a small area you may not struggle that much anyway.

If possible do get an extra pair of hands round to help though. When I was doing the floor in our much larger kitchen it was very helpful having one person to pour and prod and a second mixing up the next batch to keep things flowing before the poured mix had a chance to go off.

If you need to move about on the floor while pouring a pair of garden aerating spikes to pop on your shoes can be quite handy.

With that size floor it’ll easily self level and as mentioned above if you’re tiling it, it doesn’t have to be billiard table flat. If you’re a bit nervous about it get a mate to mix up and you’re leveling. I love doing it…it looks great when it’s done. Shame it gets covered up really?.

Ace, that saves me a fair bit of bother then!

Flat is fine, I’m tiling over it, so I’ll just truck on and pour! It’s only 2 bags so I’ll try and drag a mate in. Ta!

2 bags?!  How deep do you need it?  A bag/bottle of Smoothing compound (better name than ‘self’ levelling) covers about 5m2 at 3mm thick usually.

It’s as much as 35mm out at one end, and the deep fill stuff only goes down to 3mm, not feather edge.

So I averaged that out at 20mm all over.

1 bag does 3.1m2 at 5mm., so 10mm on 1.5m2

Hence 2 bags. Have I done that all wrong?!

A few screws in the floor with the heads at the height you want it to be at is a cool little trick an old boy on a job showed me. Can whip the screws out after, incase you’re worried about rust spots.

We use a trowel and a spiked roller when we do it to any decent depth. The roller helps get the air out.

Make sure you tape/shutter/block up anything that the leveller could go through too. It’s amazing how small a gap it can sneak under.

It’s really pretty easy. Just make sure you’re good to go before you start mixing, to give yourself maximum time you can.

My top tip for self levelling – don’t start with a bucket with a hole in it.  Queue lots of running around for gaffa tape, clearing the patio afterwards etc…

Have you got a mixer paddle to go in a cordless drill. Measured amount a water in your bucket, pour bag in Mixing at same time. Mixing a bag then takes about a minute. Pour, then onto the next bag.

Oh, I think the coverage numbers are a bit optimistic, if I where you I’d have another bag to hand.

It’s as much as 35mm out at one end, and the deep fill stuff only goes down to 3mm, not feather edge.

So I averaged that out at 20mm all over.

1 bag does 3.1m2 at 5mm., so 10mm on 1.5m2

Hence 2 bags. Have I done that all wrong?!

ah right, didn’t realise you needed it so thick.  Sums sound about right.

Thanks all! All tips taken on board. Mixed 2 batches in builder’s trugs at the same time, poured a bit in, trowelled to edges, depth marker as shallowest point 3mm above floor. Now hardened a bit, popped a level on, and it’s bob on. Awesome.

Wish I’d remembered to take the depth marker that I’d screwed to the door frame out while it was wet, but it’s just a small hole I can fill easily! 😀

Glad it went ok. It really is simple if you plan it right!

no experience with concrete, whatsoever.

but, if water naturally levels out, maybe this process can be assisted if there was some kind of perforated mat that could be laid out prior to the application of concrete.

connected by a hose, compressed air could be blown in. The bubbles would agitate the concrete, smoothing out any lumps and keeping the mixture fluid enough until it sets.

Or would it just end up packed full of voids?

Make sure you tape/shutter/block up anything that the leveller could go through too. It’s amazing how small a gap it can sneak under.

And then make sure there isn’t a new Bentley parked under anything that the leveller could go through.

Mrs kilos’ boss had their car bonnet and windscreen levelled out for them by inattentive builders a few years back.

I like the screw idea. Or could you rig up some string/chord like I’ve seen for brick work to give you something to judge against. Or a Laser spirit level?

You vibrate concrete to get it level and remove air of I remember correctly.