Mosaic fitting advice - "dogtooth" confusion

[dean jones]

Hi everyone,
New to this forum, but having only read threads as a non member (very useful advice and tips, so many thanks!) thought I'd join up and try to get some advice on fitting my mosaic borders.
I've fitted large tiles leaving gaps for a mosaic.
So, 5mm adhesive + 10mm main tile = 15mm gap to wall. My mosaic is 8mm glass/stone so 7mm short of the wall. I wanted to use the dogtooth method. Make a wooden jig 9mm deep, fill the gap with adhesive and scrape flat. Keraflex adhesive , not rapidset but a stiffer mix setting and leaving it wet. Then push the mosaic so only 2mm pushes back on wet adhesive and hopefully pat it level with the tiles. Will it work?

I've seen tillers on this forum leaving the screed to set and then troweling more adhesive over it and then fixing. Being an amateur, I would rather do it in one go to make it easier, and I've never used rapid cement. Should I leave the adhesive flat as I am only pushing 2mm, so hopefully it wont go through the gaps. Do I need to comb some grooves into it? Would it be better to leave the wet adhesive for 10 minutes so it's drier, or leave it wait and fix the mosaic straight onto wet? Please advise
(sorry for long winded thread and taking up your time!)

 

[Time's Ran Out]

Although you may prefer to do it in one go if you are filling the gap with 9mm deep adhesive you may find it slumps if too wet and if you make it dry/ thick the mosaic may not stick!
Fill it with rapid set to within 2mm of the mosaic thickness then when set just top up 2/3mm fresh adhesive and fix mosaic flush with other tiles.

 

[WetSaw]

You use the dog tooth method to bring the substrate to the correct depth. Then, once that layer has dried, comb a layer of adhesive and fit the mosaic. Trying to fit mosaic to a deep bed of adhesive will probably end badly. Tiles won't adhere properly to adhesive that has started curing.

 

[WetSaw]

Beat me to it TJ!!

 

[Andy Allen]

I've ever had a problem doing it in one hit.........I use a grout float to make sure there bed in properly .

 

[WetSaw]

I've never had a problem doing it in one hit.........I use a grout float to make sure they're properly bedded .

😉

 

[dean jones]

That was where my confusion was - I've read both methods on these boards and wondered if I could do it one go. I do have a dip on one wall where I had to pack a few tiles out with the same adhesive before letting it dry overnight. Next day I then tiled over with the same keraflex. Was worried about using rapid set as never used it before and sometimes I'm a bit slow and cautious (tiling can be a bit daunting for an IT desk-jobber come DIYer)

I may try the one go method on a short strip and see how it goes and if it doesn't work, then use the "proper" method. Tell me Andy, do you just push it level straight after applying, or do you do you wait a bit and then mosaic? How about the surface of the adhesive? is it ok to leave it flat, as I don't have a trowel that can get into the thin stripe. Should I score a few lines with some plywood with grooves in?

 

[gamma38]

There is always tile backer boards if you are worried about using a rapid set or doing it all in one go with the dog tooth method. They come in all varying thicknesses. Cut with a stanley knife. You could use these and work at your own pace, set it to the depth you require and have a nice flat surface to fit your mosaics.

 

[Time's Ran Out]

As you'd rather listen to a partimer and had already made your mind up / I'll leave it there. 😉

 

[Andy Allen]

The adhesive will be OK flat.
I normally spread about a meter then stick the mosaic in....just make sure you give it a good pat with a grout float.

 

[Flintstone]

I would strongly recommend using beva mosaic mesh

 

[Chalker]

Let it dry, then use a 3mm float.
You won't save any time, as any saved will be used cleaning the adhesive out of the joints.

 

[dean jones]

I do appreciate all the input from everyone - pros and partimers alike, and am very grateful for any advice I can get. Unfortunately, my skill levels for tiling are no where near as high as software engineering, so I often choose a method I'd be capable of, rather than the correct, tried and tested professional one. I've taken both suggestions on board and will most likely attempt both at the weekend. The "good pat in" and the bringing it just short of level and then 3mm trowel for larger sections. Better do that tonight, so it will be well dried in time for the weekend.

Localtiler - I did consider beva mesh, but I was wary about how it would work out. Doesn't it reduce the actual bonding area at the back of the mosaic, as the mesh will be another barrier between mosaic and adhesive. I figured it would be better to have 100% contact with the back of the mosaic, rather than 70 odd with mesh. Mesh would be more useful to me to fill in all the gaps left from getting the brickbond pattern to come in line - all those cuts and getting them in line!!!
I also need to consider the daunting challenge of grouting it all afterwards - all those grout lines - I predict nighmares!!

 

[Andy Allen]

You fix the mesh to the back of the mosaic the spread a layer of adhesive over it to fill in the voids.....they do work .

 

[dean jones]

I thought you just peel off the mesh cover paper and stick the mosaic to it. Then spread adhesive over the wall as in normal tiling and push the dry mosaic mesh onto it. Do you spread the adhesive over the mesh with mosaic on it and then push it onto a wall with no adhesive on it?
Also, any useful tips on grouting? as there are a lot more lines and smaller, more closely packed then a field tile. The pushing grout in using a float should be straightforward, but I imagine the wiping with sponge is a bid fiddly and needs good technique and experience. I'll be using BAL micoflex (wiping after 15min according to packet) as I have done previously, but only on normal tiles not mosaics (first time.)

 

[Andy Allen]

No. ...spread the adhesive flat on the mesh to fill the voids and spread the wall with a notched trowel and stick them on.
Just grout as you would any other tile if it's glass mosaic you may need to leave it longer to firm up.

 

[Flintstone]

Grouting mosaic is very easy unless there big pebble type.

 

[dean jones]

Most instructions and videos just apply the mesh straight onto adhesive wall, not to mesh and wall. So your method is:
Self adhesive mesh onto back of mosaic.
Tile adhesive onto back of the mesh/mosaic (let it dry or fix whilst still wet?)
Adhesive on wall and then fix mesh/mosaic

I suppose the tricky bit is getting depth correct as now you have wall adhesive and adhesive with mesh and mosaic together.

Grouting - I do have glass amongst my mosaic, so I shall leave it on longer before wiping. Normally micromax is 15min, so will leave it for 20min.

 

[Flintstone]

Mix the grout a little stiffer, and just feel at it, when it feels right, wash it off.
The mosaic fitting isn't all that technical, your skimming up the back of the mosaic with the mesh on to ensure the adhesive reaches the tile it's self. There main purpose it to stop the mosaic from being floppy and moving around

 

[Martyn Leeds]

No doubt there will be a very good local tiler in the area, maybe even struggling to fill his diary up. Might've been a perfect job for him, and everyone involved, perhaps.

 

[dean jones]

Thanks for everyone's help and advice. Went with both methods in the end ("dogtooth" wooden jig to bring it level and 3mm trowel for most areas. Flat screed layer and pushing the mosaic onto it for tricky to reach places) and skipped the mesh. Pretty good all in all and almost finished grouting too. Decided to grout mosaics separately from all the rest of the tiles.

 

[dean jones]

Thanks for everyone's help and advice. Went with both methods in the end ("dogtooth" wooden jig to bring it level and 3mm trowel for most areas. Flat screed layer and pushing the mosaic onto it for tricky to reach places) and skipped the mesh. Pretty good all in all and almost finished grouting too. Decided to grout mosaics separately from all the rest of the tiles.

 

[gamma38]

Show some pics.

 

[dean jones]

will get around to it when it's done. Not tempting fate just yet, as need to refit all furniture and how it goes back into place. Also, posting on a tillers forum I'll be putting my head over the parapet, and no doubt, will get it blown off with a shotgun! Chuffed so far, but then it's my DIY eye, which is squited compared with your guys 20/20 vision!