External Mosiac Advice needed

[Art mo]

Hi everyone

Firstly, I hope this is posted in right place? apologies if not.

I am about to embark on a project with my students to produce an external mosaic tree, which will be approximately 10 ft tall. My concern is the board. I have considered treating marine ply with yacht varnish but have been reading, on this site, about backing board used in wet rooms etc. Would this be durable enough for outdoor use? am also unsure of which adhesive and grout to use. The tree is going to made in peices and erected (drilled) onto a brick wall in our college garden, which will be visible to all, gulp!

I have made mosaics previously, but not for outdoors.

I would appreciate any advice, thanks in advance.

[Bri]

You are right about the cement board. Hardie backer is available 12mm thick and this would be my choice for your task. Ply would deform if it ever got wet. Your artwork will last for years if you use a cement board. All the best with the project.

[Aqua Tiling]

you wanna speak to mosaic girl mate...

[Art mo]

Thank you for your reply. Do you know if it can be cut into shapes?

[Bri]

Thank you for your reply. Do you know if it can be cut into shapes?

It can be cut to any shape you like (you may need a grinder or electric cutting tool), wear a dust mask though. To answer the adhesive/ grout question, use a flexible cement based adhesive (powdered in bags that you add water to) and a flexible grout.

[Art mo]

Cheers, I have PM'd her.

[Art mo]

Cheers, i have P.M.'d her

you wanna speak to mosaic girl mate...

[Dave]

Hardibacker boards are NOT suitable for exterior use....

My choice would be a thicker Aqua type panel board..

Aqua panel Exterior is a good choice.. Knauf Aquapanel Exterior Cladding System - Intro & Components

[Bri]

Hardibacker boards are NOT suitable for exterior use....

My choice would be a thicker Aqua type panel board..

Aqua panel Exterior is a good choice.. Knauf Aquapanel Exterior Cladding System - Intro & Components

I didn't know hardie's couldn't be used outside, think I need to do a bit of reading up.

[Dave]

I didn't know hardie's couldn't be used outside, think I need to do a bit of reading up.

I asked them about this a while back Bri.. and the answer was Nope.... only interior..

[Bri]

I wonder why they have those little display models in the shops with a piece of the board submerged in water? Surely if it can withstand that it can go outside? Unless it can't take low temperatures. Did they give you a reason why?

[Dave]

I wonder why they have those little display models in the shops with a piece of the board submerged in water? Surely if it can withstand that it can go outside? Unless it can't take low temperatures. Did they give you a reason why?

On the button Bri, down to frost etc and they just will not guarantee it outside


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[Bri]

I've just read the PDF and it's in there. So that's me learnt something today!

Art mo, my above advice is incorrect so please don't use hardie cement board.

[Art mo]

Thanks Dave, its quite a minefield!!

Hardibacker boards are NOT suitable for exterior use....

My choice would be a thicker Aqua type panel board..

Aqua panel Exterior is a good choice.. Knauf Aquapanel Exterior Cladding System - Intro & Components

[Art mo]

No probs, thanks for your input

I've just read the PDF and it's in there. So that's me learnt something today!

Art mo, my above advice is incorrect so please don't use hardie cement board.

[user123]

HI, I'm back, did you get my PM? Yep Aqua panel or wediboard is your only choice, what mosaic material are you planning to use?

[Art mo]

Hi there
Yes I did, cheers.
Am using broken glazed ceramic walls tiles. not sure about the adhesive or grout yet?

HI, I'm back, did you get my PM? Yep Aqua panel or wediboard is your only choice, what mosaic material are you planning to use?

[user123]

Hi there
Yes I did, cheers.
Am using broken glazed ceramic walls tiles. not sure about the adhesive or grout yet?

Ah, you know I had a feeling you were going to say that when you mentioned a group project. Glazed ceramic wall tiles aren't frostproof...

[Art mo]

Oh dear........as this is quite a big 'tree', I think tesserae would be too expenisve. Any suggestions?

Ah, you know I had a feeling you were going to say that when you mentioned a group project. Glazed ceramic wall tiles aren't frostproof...

[user123]

Oh dear........as this is quite a big 'tree', I think tesserae would be too expenisve. Any suggestions?

You're not going to get cheaper than vitrified glass, Linda, porcelain will cost more and stain more easily, too, definitely go with the glass, it's still so easy to nip, no more dangerous than ceramics, really, in your group situation - you may have to ask for goggles to be worn, depending on the health and safety regs at your place, you'll need to provide nippers, wheeled ones cheaper than the Leponitt once are available from the forum sponsor TradeTiler, they are good, I use one myself, I alternate with the Leponit one. Longer handled so more leverage, even though the leponitt wheels are sharper.

[Art mo]

Thanks, I have just looked at TradeTiler for the nippers. I have a few of the other type so hopefully we can use both. I've not used vitrified glass before, sounds interesting. Looking forward to trying the wheeled nippers too. Any advice on adhesive and grout? I have read that a flexible adhesive is best?

[user123]

As to the adhesive - don't know what tile shops you have in your area, go in and ask for a powdered adhesive suitable for swimming pools, same with grout. 3mm mosaic trowel. Don't accept anything else. How are you planning to do the mosaic in the first place, directly onto the aquapanel, on mesh, reverse method, what? It's big, I feel a little uncomfortable here, ...

[Art mo]

Direct onto the aquapanel....the tree trunk will be made in 3 peices and the students are making a circular plaque (approx 15" diameter) each which will be placed at the end of each branch. Am thinking it best to have batons screwed to the wall and then apply the tree and plaques to the baton. Will drill holes before tiling. Does that makes sense. Thanks for the info so far, am very grateful.

[hillhead]

Adhesive wise Gisela would mapei kerafex or even P9 do the job?
For grout - mapei untracolour?
Also Art Mo you're going to need plenty of pieces,lol.
The best of luck and i hope you keep us up to date and nice pics possibly?

[user123]

Joe, I'm going to ignore you for a sec... Linda, I'm with you design wise, but really wouldn't go for the direct on the aqua panel approach. Why? because of the working time of the adhesive, if you are working in a group situation you'd have to hand out little cups of perfectly mixed adhesive for each person to deal with as if it were glue, and you're going to lose control over if it's still any good to use. Also, if you work directly like that, changes at the end are much harder to do, things like sufficient gaps for grouting, if it's not just you working on it, your eyes would have to be everywhere in minute detail. Work on mesh, it's still a direct approach to give that instant satisfaction to your group, but it gives you the chance to correct things before you sink each plaque into your adhesive, which is nice and fresh still then, and you can also press it down with a groutfloat to make it flatter. Have you worked on mesh before?

[Art mo]

No .....and now I'm scared!!

[Art mo]

Had to look up groutfloat! I like the sound of this but as never done it, it sounds quite daunting. See what yo mean about the adhesive though. Hmmmmmm

Joe, I'm going to ignore you for a sec... Linda, I'm with you design wise, but really wouldn't go for the direct on the aqua panel approach. Why? because of the working time of the adhesive, if you are working in a group situation you'd have to hand out little cups of perfectly mixed adhesive for each person to deal with as if it were glue, and you're going to lose control over if it's still any good to use. Also, if you work directly like that, changes at the end are much harder to do, things like sufficient gaps for grouting, if it's not just you working on it, your eyes would have to be everywhere in minute detail. Work on mesh, it's still a direct approach to give that instant satisfaction to your group, but it gives you the chance to correct things before you sink each plaque into your adhesive, which is nice and fresh still then, and you can also press it down with a groutfloat to make it flatter. Have you worked on mesh before?

[Art mo]

Hi there

Yes, will take lots of photos, think this is going to be quite a challenge.

Adhesive wise Gisela would mapei kerafex or even P9 do the job?
For grout - mapei untracolour?
Also Art Mo you're going to need plenty of pieces,lol.
The best of luck and i hope you keep us up to date and nice pics possibly?

[user123]

Adhesive wise Gisela would mapei kerafex or even P9 do the job?
For grout - mapei untracolour?
Also Art Mo you're going to need plenty of pieces,lol.
The best of luck and i hope you keep us up to date and nice pics possibly?

I'd prefer Keraflex, Joe, because of the longer opening time... but really feel as long as it's worked properly on mesh and any good powdered swimming pool adhesive is used - Linda may not be able to get hold of Mapei where she is, Ultra is pretty good, too, and often easier to come by, either will be fine.

[user123]

No .....and now I'm scared!!

Ok, the idea to work on mosaic mesh is to fix the glass tesserae to the mesh with tiny dots of the most hated term her on TF, waterproof PVA. I say tiny dots, because theit job is to hold the glass to the mesh that has a very open weave so that the cement adhesive, when the mosaic is pushed onto it, seeps through the mesh and grabs the tesserae. The PVA will NOT hold the mosaic in the long run, it just serves as a temporary hand to hold things in place. So the main message to yourself and your group would be to NEVER cover all of the glass with the PVA - it would, even the waterproof version - come life again on contact with the cement and eventually all the pieces would just drop off. So just little dots, ok?

Draw the designs on paper with a marker pen, cover the whole thing with two layers of clingfilm, tape down, nice and flat, then same with the mesh above and then stick your glass to the mesh with tiny dots. Leave to dry. When dry remove the tape, the mesh should lift up with the glass on, ready to set into the adhesive.