16x10" wall tiles 8 or 10mm notched?

[DarrenThomas]

In a week or so I'll be doing our bathroom and wifey wanted 16x10" tiles with 24x3" border. Just checking which notch depth I should be going for.

Some walls are skimmed others are just render.

The border tile is a couple of mm thicker than the main tile. Since its smaller am I going to be ok with a smaller depth to even it out?

I've gone for 3mm spacers

 

[Richard C]

What weight are the tiles, plaster has a maximum limit of 20 kg/sqm but that includes up to 4 kg/sqm for the adhesive/grout so anything over around 18kg/sqm & you could have a problem. The render should be OK, as long as it’s sound it will take up to around 40 kg/sqm.

You must use cement powder adhesive only for tiles that size not tub ready mix or it will take an age to set & sometimes never does. When using powder addy, plaster must be acrylic primed to avoid a reaction between the cement in the addy & gypsum in the plaster. I usually use Rapidset but it only has a pot life of 45 mins so only mix up as much as you can use in around 30 to give you time to clean your tools & bucket between mixes (very important)

For the size of your tiles you need a solid bed trowel; I generally use a thick bed trowel - 20mm round notches, 10mm deep, at 28mm centres. On really flat walls you can use a thin bed trowel - 10mm tapering notches, 5mm deep, at 12.5mm centres but stick with the larger one if not sure as larger tiles need a nice flat surface or they can end up all over the place. The border will be fine with a thinner bed but let the adhesive set before you start tiling above or it could all start moving about.

I advise you read the Tiling Sticky & Forum Archive posts before doing any more work or buying materials, it could prevent you making disastrous & potentially expensive mistakes. It’s important to use only quality trade tilling materials of the correct type for your tiles & tile base; cheapo own brand & DIY stuff is mostly crap.

 

[DarrenThomas]

Hi Richard, thanks for the reply.

The tiles weigh 1.2kg each and are 10 per sq m. That leaves me with some headroom on the weight front.

I was sold some cement based powder adhesive by tilebase (where I got the tiles) which is weber.set plus. I've only ever really seen Bal bounced when I've looked before but I never really looked that intently. It seems to be a reputable adhesive from my searches post sale.

I noticed on the packet that it mentioned priming plaster so I'll pick some up before I start.

As for trowels, am I correct in my thinking that a solid bed trowel differs from a square notched trowel because it has different shaped notches? A square notch will maybe give 60% adhesion because it doesn't flatten as easily as a round or tapered notch which maybe offers a 90%+ adhesion?

 

[Richard C]

The tiles weigh 1.2kg each and are 10 per sq m. That leaves me with some headroom on the weight front.

As long as the plaster is sound & isn’t blown then you should be OK.

I was sold some cement based powder adhesive by tilebase (where I got the tiles) which is weber.set plus. I've only ever really seen Bal bounced when I've looked before but I never really looked that intently. It seems to be a reputable adhesive from my searches post sale.

The Webber Set will be fine.

I noticed on the packet that it mentioned priming plaster so I'll pick some up before I start.

As I said, standard procedure for powder adhesive over gypsum plaster/plasterboard; it must be acrylic primed to avoid a reaction between the cement & gypsum in the plaster. Generally though, don't prime unless addy manufacturer recommends it.

As for trowels, am I correct in my thinking that a solid bed trowel differs from a square notched trowel because it has different shaped notches? A square notch will maybe give 60% adhesion because it doesn't flatten as easily as a round or tapered notch which maybe offers a 90%+ adhesion?

Yes more or less, it’s to do with the shape, depth & pitch of the notches. A solid bed trowel will give >100% adhesion if properly used & there is an even bigger one when tiling really large format tiles on floors. Good adhesion & support is essential for floors & on walls in wet areas but you can use a standard, round notch trowel (6mm round notches at 12mm centres) for walls in dry areas which gives approx 70% coverage. It will save a bit of addy but, personally, I never bother & stick with the thick bed trowel.

 

[DarrenThomas]

Thanks once more Richard.

I've picked up a Rubi 10mm U notch trowel, a marshalltown grouting float and a whisk for the adhesive/grout.

 

[Richard C]

Blimey mate that’s serious gear for a one off DIY I’d have gone with cheapo BNQ, they do a reasonable plastic notch trowel & sponge float & I think the pair come in at less than a tenner; they would have served you perfectly well & lasted long enough to tile your whole house.

If using a drill whisk for the addy, keep it at slow speed & don’t over mix or "pump" it or you will introduce too much air & drastically shorten the pot life/set time. You don’t need a mechanical whisk for grout, I use a wooden kitchen spoon

 

[DarrenThomas]

Blimey mate that’s serious gear for a one off DIY I’d have gone with cheapo BNQ, they do a reasonable plastic notch trowel & sponge float & I think the pair come in at less than a tenner; they would have served you perfectly well & lasted long enough to tile your whole house.

If using a drill whisk for the addy, keep it at slow speed & don’t over mix or "pump" it or you will introduce too much air & drastically shorten the pot life/set time. You don’t need a mechanical whisk for grout, I use a wooden kitchen spoon

I've dropped 2k on a bathroom, 35 on a few tiling bits that i'll have for the future is nowt. And I like proper tools

I'm only 26 so they'll get plenty of use over the years!

Thanks once more for your help. And thanks for taking the time.