Grouting Slate Floor

[Christian McArdle]

Well, I've collected by 60x40 Bamboo slates from Stonell. I've got my ArduFlex 7001 Timber System and ArduFlex FL grout. I've got a week off next week. Some questions for those who've already laid their slate floors.

1. My planned order is the following. Is this sensible?

a) Sort slates by height and randomize colours. b) Lay out on floor, cut to size and number reverse for relaying. c) Lithofin MN Power Clean d) Lithofin MN Colour Intensifier e) Lithofin MN StainStop f) Lay tiles on ArduFlex 7001 TS g) Grout with ArduFlex FL h) Clean grout i) 2x Lithofin MN StainStop j) Lithofin WEXA

1. Most grouting tips suggest making as little mess with the grout as possible as it is hard to remove. However, both the Stonell instructions and the grout instructions say to float the entire floor before sponging off. They say this provides a more even finish as just grouting the lines leads to patches of grout at the tile edges, but a spotless interior. Who is right, here?

1. To clean grount, do I just use water? Should I use WEXA, PowerClean or CementAway as well?

2. I have a electric diamond blade tile saw and a 115mm angle grinder with diamond disc. Which will be better for cutting the slate? Would the angle grinder need water or other lubricant/coolant to work effectively?

[Neil Jones]

instructions and

I laid a limestone floor, so not directly relevent.

However, the main difference was that I laid the floor before applying any cleaners or other products, then used WEXA to clean up. Also, I cut the tiles as I went along, but I couldn't say whether cutting them all in advance is better or not.

I used stainstop on the floor before grouting, as you say, but once grouted I didn't need to clean it before applying stainstop - do you think it will need it?

I found that the grout I used (which was Howdex I think) was easy to get off the tiles (thanks to the stainstop, I assume) with a sponge and clean water so I imagine this is why Stonell are saying to just float over the whole floor.

Finally, I haven't used the WEXA since the floor was laid, just the easy care, although I had a delivery yesterday of some grout cleaner and some more stain stop as after 2 1/2 years I think it could do with it.

Neil

[Christian McArdle]

I suppose the main reason I was thinking of doing the initial treatment outside was to keep the floor usable for longer. With all the drying time required between the treatments, it would end up with the kitchen unusable for too long. It would certainly be more convenient to do it in situ, though, if I can think of a way of getting rid of the family for a day.

How did you cut the tiles?

That sounds good. Just a sponge it is.

BTW, how long did the entire process take? How many square metres did you lay?

Christian.

[Neil Jones]

applying

treatment

Day trip to the zoo or something?

Electric diamond-blade tile saw.

I probably don't need to say (but will anyway) that you need to clean it up fairly quickly before it goes off. Otherwise you will need those other products...

It took me about a day to lay the floor, which is about 3m by 2.5m. After that the most time-consuming part was waiting for the next treatment to take effect so you can move on. I finished off over subsequent evenings.

I made 2 mistakes doing this job. Firstly, I didn't level the existing floor up, instead I relied on adhesive to make the levels - if I'd have been laying onto a level surface first it would have been much quicker. Secondly, the adhesive and grout were both supplied dry to be mixed with water - I mixed this by hand whereas I should have at least got a plaster-mixing-type drill attachment.

[Christian McArdle]

OK, I've already laid plywood over the whole floor, so it is reasonably level.

I wouldn't dream of mixing any cement/plaster/grout by hand!

Christian.

[Neil Jones]

I was young and naive, what more can I say? :-)

Neil

[Christian McArdle]

So was I, once, until I built a brick barbecue...

Christian.

[Andy Hall]

You'll need it :-)

Yes.

You can do that or cut as you go. The tiler that did mine cut the slates in batches as they were laid. It may not be practical to cut the lot.

Have a look through the slates for fossils. Fossils or imprints, especially of leaves are quite common. You might like to place those where they can be seen

Yes to those.

I don't know these products. The tiler that did mine used Howtex. This was on concrete though,.

At the right time.

That is better. Mine were done a room at a time because the area was large.

The tiler that did mine worked mainly along the lines but working sideways to some extent as well, then cleaned off. There was no problem of grout migration to where it wasn't wanted.

Mine just used water, but it wasn't the same type of grout.

I doubt if you will get much joy with the angle grinder.

A tile saw works well but you need to go slowly. If you have one of the normal domestic sized tile saws, it may not be man enough for this size of tile - they are quite heavy - right? You might need to think about hiring a big one and that could well save time.

.andy

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[Neil Jones]

At least I had big biceps for the rest of the summer :-)

[Andy Hall]

Don't be too optimistic on how long this is going to take, Christian.

I don't know how big an area you are talking about, but this is a time consuming job if you want to do it properly.

I would think about having the kitchen out of commission for more than a day and come up with some alternative arrangements for cooking etc.

Also, there is the issue of letting the adhesive go off for plenty of time before grouting - especially with flexible adhesive.

It would be tragic if you rush it and end up with cracks in the grout

Professional tilers took about 7 man days to lay 50m^2

.andy

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[Christian McArdle]

That's why I wanted to get the time consuming chemical applications done separately. Once they're ready, that leaves just sticking then down, grouting and sealing to be done with the kitchen out of commission.

The adhesive accepts light foot traffic and grouting after two hours. It is specifically designed for flexible timber floors. I suspect there would be an overnight gap between them anyway.

I have 4 days total, although would prefer to spend less, as I have loads of other work to do, and would certainly prefer the kitchen usable for much of this time. I have 12 square metres to lay.

Christian.

[The Natural Philosopher]

Took me 6 weeks on and off to lay that much. Saw a lot of test matches tho :-)

[The Natural Philosopher]

Take your time then.

Be VERY careful of slow setting flexible adhesive, and mix it as stiff as you can. It tends to slump badly. I reverted to fast set non flexible, which is stable after a couple of hours.

I was laying very thick beds tho - up to an inch in places where the floor was uneven.

Don't be tempted to dab and dot. The slates WILL come loose.

Each row, clean up absolutely with sponge and wter, and then seal it immediately. Leave overbnight and you can use it temporalily

seal throughly before grouting. Only grout a little area at a time then CLEAN UP THE GROUT before proceeding.

I would allow 4 weeks of careful patient 4 hours a day sort of work.

[Toby]

I picked up a radial tile cutter rather like the Ferm item 35263 at SFX, from B&Q. Before you all shout, I know it's only one of their own brand jobs, but for £80 (& -20% offer) was the same price as an entry level Rubi hand slide cutter. It's a heavy 30kg thing, with a rubber mat on the bed, with a fairly good

180mm diamond wheel and 600w motor on an overhead slide bar. It all sits in a water tray with a small pump to wet the blade. The mitre gauge can stay in the box. Images> just wish I had a 600x400 slates to put through it. I would recommend it for this job, in fact it is the only BnQ product I would recommend for any job. (I've told the Mak & DW tools to stop sulking, this is the only interloper)

[Christian McArdle]

It is rapid set adhesive (Arduflex 7001 Timber System), which claims to be stable after 2 hours. I'm going for a 3-4mm bed, as recommended by the adhesive manufacturer. The 3mm bed costs about 100 quid in adhesive. An inch would be getting on for a grand!

Yes, I always ensure full bedding of tiles, even wall tiles. I usually use the best adhesives I can find (i.e. bathroom tiles get put on with adhesive recommended for commercial swimming pools).

That is simply not possible. I'm a fast worker, though. I have to be, the amount of renovation this place needs. It can't take more than an hour to apply a coat of chemicals to 12m2. I have 7 layers of chemicals to apply (1 x Primer (to timber), 1 x Power Clean, 1 x Colour Enhancer, 3 x StainStop, 1 x WEXA). Once pre-cut, laying the tiles will only take an hour or so, surely? The sorting, laying out and cutting should be the most labour intensive part.

Christian.

[Andy Hall]

That might be a bit optimistic, depending on the extent that you can sort the tiles. It might be worth getting extra on a sale or return basis so that you don't have to stop.

I'm not sure where you got the adhesive, but last time I did some tiling, Just Tiles in Woodley would accept returns.

I think you are being optimistic. It is really important to achieve levelling as best as you can locally from tile to tile and then over an area. A long level is helpful for this, but it is time consuming to get right.

Precutting the tiles may be risky because you may not be able to achieve precise spacings between tiles. It isn't like using the little plastic spacers on wall tiles......

I think you are going to be surprised at how time consuming and tiring this is. You are going to be holding an manipulating quite large weight at arms length........

.andy

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[Christian McArdle]

Well, I've got 66kg, which should be enough for 4mm. The plywood is obviously pretty flat to start with.

So you don't think presorting by height and maintaining an approximately constant 3mm adhesive bed thickness will be sufficient? The bed should provide 1mm of adjustment or so to each tile. I do have a good quality long level to help, though.

Using such large tiles, though, means that there is a lot less leveling to do. Levelling 15cm smooth ceramic tiles, where any uneveness will show immediately would be much more difficult, I would have thought. There's only around 45 tiles to lay (with 6 spares). Even 2 minutes on each tile with a hammer and level would only take an hour and a half.

I see what you mean. I had intended to draw lines as to where the tiles were supposed to go (using 5mm plastic spacers), so I didn't have any cumulative positioning errors when it gets close to obstructions further down. Do you think this plan will not work?

Yes, there's around half a tonne of the stuff to fit. The amount the floor pan dropped when the forklift dropped it in was quite astonishing. No wonder the thing came with adjustable headlight aim.

Christian.

[Stephen Fasham]

I laid a kitchen floor in Slate a couple of years ago, 13' by 8'. I didn't prepare the tiles before laying and methodology was roughly:

1. Select tiles and lay as you suggest (although I laid out a grid between the skirting in string before starting as I found the tile sizes were not terribly accurate and I was worried about starting in the middle and finding the lines curved at the end). I did a full dry lay including all cutting (angle grinder with stone wheel, worked greater even complex corners).
2. cement them down, which I did individually just with the adjacent tiles lifted off the dry grid. I basically buttered the back of each tile (like bricklaying) rather than spreading adhesive on an area of floor as this made it easier to try and match the edges up for height. This also avoids the problems of lifting and breakage with the dab and dot method (no breakages despite heavy and at times inappropriate use!). Any adhesive that got onto the tiles was removed immediately with the favoured wet sponge.
3. Two coats of stain preventer stuff
4. Grouting - just the lines, not sure about yours but given the riven nature of my slates (Wickes) the idea of floating the floor would have been a disaster. Most of the cleanup was done with the wet-sponge.
5. Follow grouting with use of cement grout remover (Wickes again) to ensure any film of grout was taken off.
6. Finish off with 2 coats of polish.

All tile cutting was done with an angle grinder with a standard stone wheel, which I've also used on roofing slates. No lubricant/cooling and I was able to cut corners out for round the door (carefully) - I think I broke two tiles, 1 corner and one that I dropped (now under the cooker).

It did seem to take an inordinately long time (mostly waiting) but the final effect was great, and follow up care was just washing (probably more occasional than it shoul have been!) and the floor still looked great when I sold the house earlier this year. - Now I've got to do it all again in the larder of my new house as soon as it's no longer a shop storeroom.

If I was doing it again, I can't think of much I'd do different. Except of course that I mixed the adhesive and grout by hand!

This was a concrete floor but I've used the same method on a wooden bathroom floor, plus the relevant primers etc.

Happy to help if I can,

Stephen

[Neil Jones]

That was my original plan but I found that my adhesive obscured the lines I had drawn :-)

In fact I did use tile spacers when I laid my floor but the tiles were very square with uniform thickness - I doubt your slates are the same.

[Andy Hall]

I think that you'll have difficulty in sorting them to that kind of tolerance and you may need a thicker bed to allow for more vertical adjustment.

It's more thickness compensation. You may find that you don't have the leeway for as much sorting as you think.

It would be worth doing a sort and finding the thickest and thinnest.

I think it will likely be longer because you have to level and adjust the height. It isn't as easy as it sounds unless you have been lucky with the thicknesses that have come in the batch.

One problem is covering the lines with adhesive. The other is that the slates are not cut to the same fine tolerances as machine cut ceramics. You will probably find a variation from tile to tile. It may only be a mm or even a bit less, but I would be surprised if you could end up with perfectly equal grout lines. In the context of the cleaved surface and the overall effect, this doesn't matter as long as it's only a mm or two here and there. It's a natural material and so looks OK.

What colour grout are you using? Generally a grey is a good idea because it tends to not stand out against the slate. Maybe a lightish grey with the Bamboo slate?

That's another reason for suggesting taking your time to avoid doing your back in.

You might also consider some kneepads if you don't have them. I've tried several different kinds and found the gel ones the best....

.andy

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