DIY- Self-levelling compound

[nownek]

Evening all.

I need to level the floor in my kitchen prior to installing some new units. The floor in one corner has a noticeable slope from the current corner of the room to where the (block) wall for a now-demolished cupboard was (in the front corner only- i.e. the slope is from corner to corner). It is probably an area of about 2ft2 with a slope of about an inch across it.

It is a concrete floor.

Does anyone have any experience of using self-levelling concrete and, if so, any hints and tips such that an idiot (me) could understand?

[MrV]

Latex Self Levelling compound comes in two types, first the powder and latex mix type where you buy the powder cement product and a bottle/barrel of latex liquid to mix with it, or the second which is an all in one powder product which can be mixed with water.

I used the second type, the all in one, mix with water type.

I talked to several local tiling shops and 2 local tilers, they all said that the name on the bag does not make a lot of difference, the mix and the prep is the important bit.

To prepare a floor, first know the limitation of the product. I was levelling an uneven concrete floor in a 20 year old house. The floor was stable, and extremely dry. I hoovered the floor, then rubbed off any high points, or very noticable lumps in the existing concrete with an angle grinder. Then hoovered again. I then painted a mix of 1 part PVA glue to 2 parts water on to the floor as the glue directed for sealing dusty or porous surfaces.

Next I took a long level and found the highest point in the room. I then marked the floor with a felt tip pen to remind my self where the deepest of the depressions were.

I then mixed my self levelling compound as per the instructions, thought it was a bit too stiff and added a bit more water until I got to a syrupy, runny texture. I then spread a little self levelling compound on the floor with a 12" plasterers trowel anywhere the compound would be going. This would release surface tension on the floor when I made up the level.

Next I poured the self levelling compound onto the floor heaviest on the deepest points. I used a level as a long scraper working across the floor, the self levelling compound began to dry rapidly, so I worked as fast as I could. I filled the main voids and got the minor depressions level with cost number one.

I then left it 24 hours to harden. Next day, repeated the same procedure as before, again, using a level to form the self levelling compound, focusing on the slight depressions, smoothing a lot with my plasterers trowel.

I left the compound for about 30 minutes, and went to check it. In one or two places, I had over filled and created a ridge or a lump, so I used the edge of my plasterers trowel to gently scrap off the excess compound.

I then left it to harden. On checking the level is pretty much spot on, they are still very slight undulations, of no more than half a mm across a 1.5 metre level. The floor has hardened nicely.

A couple of quick points -

1. Self levelling compound does not self level, it MUST be guided into place using a trowel.

2. The brand is not a great deal breaker if you are a DIY at home person.

3. The instructions on the packet are not necessarily perfect, go by feel for the correct consistency, the description I found accurate was cold, runny porridge, or as my mate said, grey runny snot!

4. This is an amateur set of instructions based on my personal experience of using Wickes own brand latex self levelling compound, I found it okay to use, mainly as I couldn't find anywhere else that sold this stuff!

[Trevelyan]

I did my kitchen floor with it recently and found it fairly easy to use. If you get the proper latex based self levelling compound then as long as you shove it into roughly the right place it'll flow and level itself out. My floor was all over the place before I started, so to give myself a guide to work to I drilled the floor on a 1m x 1m grid and stuck in wallplugs and screws. I then went around with a spirit level placed across two screws at a time and wound the screws up or down until I got the heads of the screws all at the same level. When it came to pouring the compound then I just had to shove it about until it came up to the heads of the screws and leave it to settle out. Other people would probably say that this was overkill, but it allowed me to keep the paddling around in wet compound to a minimum.

One other thing to bear in mind it that it isn't cheap stuff to buy and a bag of it doesn't go very far. If you've got a fair bit of building up to do then someone told me that you can mix it with gravel or shingle to bulk it up and make it go further. You could get the levels somewhere near close like this, then finish of with the normal mix to get a good finish if you wanted.

[nownek]

Wow. Great replies- thank you very much.

One more question- how long until it has gone off? The various bits and pieces I picked up searching on google give wildly varying time periods before setting things on top.

Or is it just a suck it and see approach? (not literally, of course....)

Edited by nownek on Monday 8th September 21:26

[TheEnd]

i think an inch is a little much for self leveler. i'd mix up a little sand + cement and get it closer to the height, then you can latex it.

[shirt]

for a 2ft x 2ft piece with an inch drop i wouldn't bother with self levelling compound, especially as you're only supposed to use it for upto 4-5mm.

simpy use a sand/cement mix. get rid of any loose debris and brush on some 5:1 pva:water and allow to dry.

then mix your sand/cement up and trowel roughly level, then take a long [6ftish] piece of wood, lay it flat on the floor and use it to scrape the patched area level.

if youre putting another cupboard back then this should suffice.

[MrV]

I ment to ask are you just fitting a new base unit over the low area ? if so it will have adjustable legs so it will get over any leveling imperfections plus if you are going for a tiled floor you could just use a thicker adhesive bed to get over what ever is left that is uneven.

If you do go the sand cement route(it will be cheaper ) use sharp sand instead of soft

[nownek]

It’s an exaggeration to say there’s a 1 inch fall I’ve just measured it and it’s more like 5-6mm (everything is 1 inch in my mind until I measure it...).

We’re laying down lino (for various reasons) so no chance to level it out using adhesive and the units have a strip that runs along the front so any changes in the level of the floor will stand out unfortunately.

Thanks for all of the replies- this is my first kitchen so I’m learning a lot (I'll be stealing the idea to use screws to find a level, for example).

Edited by nownek on Monday 8th September 22:15

[SS HSV]

nownek said:

everything is 1 inch in my mind until I measure it...).

I used it about 12 years ago when extending my kitchen. Unlike Mr. V I put it on way too wet. It literally ran across the floor like a small lake and I thought "Oh God, I've screwed this up it will never go off". I laid it on Friday night and left it all bank holiday weekend and on the Tuesday it only looked 'wet' around the edges. On wednesday I plucked up enough courage to walk on it as it looked all the same and lo and behold it was as solid as concrete. I tiled over this with large slab-like quarry tiles amd to date it has been fine. I used 6 bags but calculated after that I shoulld have used 8.. that accounts for the runny nose consistency instead of the bogey nose that the instructions called for

[ozzerr]

Latex self levelling will never make up an inch,sand and cement as above or why not plywood packed up sufficely no wet trade needed at all then.