Levelling floor before tiling

[silentC]

I'm just finishing off a job in the Granny flat - there was a balcony which we have closed in to make a spare room. The floor of the balcony is 12mm compressed cement sheet. We need to extend some floor tiles from the dining room through into this new room but there are a couple of problems.

The first problem is that the old balcony floor has a fall on it to provide run-off. The second is that it is about half an inch lower than the inside floor level. This is because the chipboard flooring is 19mm and there is a tile underlay on top of this.

We need to bring the balcony floor up to the same level as the tile underlay so that we can run the tiles right through. I have three ideas on this:

1. Use a self-levelling compound to bring it all the way up to height.

2. Use the self-levelling compound to bring it up to flooring height and then lay underlay over it.

3. Cement screed with the tiles straight on top.

Number 3 is going to be the hardest to get right. I'm no tiler.

Number 1 worries me as the self-levelling compound might be too thin at the top end and could crack, loosening some tiles. This is worsened by the fact that the thinest coverage is in the highest traffic area - the door way.

Number 2 - I'm not sure how successfully I can fix the underlay to the surface. It's usually laid over wood or chipboard and glued and nailed. Maybe I can screw it to the compressed sheet.

Any ideas, experiences?

[journeyman Mick]

Silent,
floor levelling compounds will work successfully down to a few mm thickness. I'd go with this option and if it comes down to say 2-3mm in the door way go back to where you've got enough depth to get a decent thickness, say 5mm and tack a strip of timber to the floor as a "dam" to stop the Ardit flowing too far. Then lay these tiles on a generous bed of glue. If neccesary get your levels right by using a straight edge off the tiles that are already down and a levelling pad of a tile on a few packers. Check with straight edge and tap tiles down with a rubber mallet till level

Mick

[bitingmidge]

Silent,

1) Don't even think about drilling and fixing into the CFC!!

2) What Mick Says

3) Not all self levelling goo is created equal, in fact it isn't all self levelling.

"Ardit" referred to by Mick is the industry standby, it is a bit like referring to a vacuum cleaner as a Hoover. It is a good product, or more correctly, range of products but make sure that you get the one to suit your purpose.

Another company that I have had some good dealings with in the past year is MBT. The link is just to their
TOPPING (http://www.mbtaus.com.au/cemflor/index.htm) range of products. I suggest you speak to a technical rep in Sydney about your specific requirement.

We had "occasion" to use their product (applied by an expert applicator) to fix our garage/workshop slab, 80m2 with depth varying from 4 to 30 mm so far so good.

If you can get the topping close or just below the tile level, you should be able to bed the tiles down to it as described by Mick. Don't forget to leave a 10 mm joint at the junction with the old work and caulk it with flexible caulk rather than solid grout, to allow for differential movement between all those materials.

Good luck,

P

[Bunyip]

Silent,

A few years ago I used an Ardit product to level an existing slab prior to tiling. The tiles did not reach all they way to the door frame (30 mm gap - it was not important ...); the point being that there is a layer of Ardit here about 2mm thick that received full people traffic going through a main door. The Ardit here is unsupported at one edge. I was going to put a capping over it, but it has never shown signs of weakening or cracking - so it is left as is. It is amazingly durable and strong.

[outback]

Just to go against the flow abit.
When we renovated our house we had a couple of areas similar to yours. The bloke that we hired and called himself a bulider assured me Ardit would be the go, even down to next to nothing thickness. In our kitchen (real high traffic area) the "Ardit" crumbled within months leaving a nice crack in the vinyl we laid.

Until now I didn't know there was specific products I thought Ardit was Ardit was Ardit, so If you choose this course Mick's idea of a dam sounds pretty clever, and be selective with the exact type of compound.

[journeyman Mick]

Outback,
"Ardit" is a brand name and they make a whole range of products, I think the levelling compound is Z8. Up here Hilti carries the stuff. The one that I have used is just amazing, you mix it up (with a drill powered stirrer) to the consistency of cream and pour it onto the floor. It then finds its own level and sets. Your "builder" may have overmixed/undermixed/used incorrect product, alternatively if there was movement in the two sections of floor under the ardit that would have caused cracking also.

Mick

[Theva]

Silent,

The stuff is Ardur K15 made by Ardex. Ardit Z8 is more suitable for filling up to 5mm, also made by the same company.

It is German, you better believe it is good ;) .

If you are applying either over compressed fibro, then there is another additive you are suppose to add to give it some flexibility.

Regards,

Theva

[outback]

Mick, I think you may have caught my drift when I used the word "builder" as I did. I really have no idea what he really used, may ahve been dirty water for all i know.

He was here for months, took all soughts of legal action to make him stick to the contract, then he stuffed things up as best he could.
On reflection I think I found the one thing he was really good at! :eek:

[dzcook]

is this self leveling stuff any good for a wooden floor i maen can i use it to level and fill ( perhaps ) the smaller gaps ( ie seal from under neath ) then use leveling compound to smooth out a wooden floor to lay vinyle over after to get a smooth finish my wooden floor has more bumps and lumps than u can imangine ?
just a thought
tks david

[journeyman Mick]

David,
best bet is to talk to a distributor/sales rep regrding your requirements. There is a huge range of products available designed for specific applications. I have seen vinyl floor layers trowel a product called "featheredge (at least I think that's what it was called) onto uneven timber flooring before laying vinyl.

Mick

[bitingmidge]

David,

The correct product (whatever that may be) can be used with caution(!) but you'll probably get away with something less if you use a hardboard underlay under your vinyl.

Most houses of the type I have gleaned from your other posts, were cobbled together (no offence) using lots of materials which would not come within cooee of meeting today's standards. You will probably find that your Bearers, Joists and Floor boards are all at about twice the span at which they are capable of supporting anything! That means you can expect a fair bit of deflection or "bounce" in your floor.

If you don't use the underlay, you'll almost certainly still see the joints in the floor below, particularly where the "ardit" cracks as the floor boards move relative to one another.

The underlay sheet will fix this and the topping will act as a continuous packer for it.

I have done this in a situation which was a bit extreme, the floor was old hardwood weatherboarding, originally packed under the lino with newspapers to disguise the bumps a little! I used masking tape over the top of the joint to stop the goo leaking out, and all worked well.

Good Luck,

P

[homerjs]

Hi there, I've been following this thread. Gaza, I want to put a thin coat of cement over my old concrete in my double garage as the current concrete is quite rough. I'd like to then paint it. I'm thinking only about 5 to 10 mm thick.

Question: Could I use self leveling compound to do this? I know I'd need heaps but surely this would be easier than mixing cement plaster and then having to spread it out and trowel it? Could I just make lots of buckets and pour it all over the garage floor? I understand I would have to use a special compound over the old concrete first (saw it in the hardware shop but forget what it's called) to help with sealing/bonding.

If not, does anyone know a cheap dyi method of making my garage floor all nice and new?
Thanks
Andrew

[Cliff Rogers]

Andrew, this thread is almost 3 years old now.

If your floor is already level & just rough, you can grind it smooth before painting it.

You can pay somebody to do it or see if you can hire a grinder to do it.
It makes heaps of dust but you will end up with a much stronger floor surface.