Mounting a Tile-Based Mural

[algebraist]

I am just starting work on what will be a mural made from twelve 8-inch tiles, arranged 3x4, so roughly 24 inches x 32 inches (plus a little extra for the minimal amount of grout between the tiles).  I have been using Frank Giorgini's "Handmade Tiles" as a reference; he recommends mounting the tiles on 3/4 inch plywood which has been braced with strips of 3/4 inch plywood along the edges, and then hanging it via yet another strip of 3/4 inch plywood which has been cleverly cut lengthwise on a 45 degree bevel, with one half attached to the back of the mural, and the other half attached to the wall (screwed into studs) -- that way the bevel on the back of the mural just slides down into the bevel attached to the wall, and the whole thing is secured.  

All well and good, but heavy!  If that's how it has to be okay, but I am wondering if I can get away with 1/2 inch plywood, and bracing it with (nominal) 1x3 or 1x4 inch pine boards (and making the support strip from the same).  Or if there is perhaps some other comparatively light option.

(Presumably the concern is that the board may warp, with potentially disastrous effects to the mural, thus the thicker the plywood the better.  But my back hurts just thinking about 3/4 inch plywood...)

Thanks.

[Mark C.]

3/4 plywood will stay flatter than 1/2 so I would not even think about using it. The better alternative is better plywood-meaning hydrotec plywood-or boat building plywood

You know about plywwod grades right?/. CDX for sheating homes and roofs-AC for exterior use like soffit trims etc

It is many layers of solid wood no voids and stays flat and is made for exterior use. I use it whenever flat needs to stay flat-it comes in thinner (usually metric measurements )and 1/2 is fine as it stays flat-of couse its heaver than regualr junk AC plywood what is what you should be using not cdx plywood. You will need a specialty lumber store for this (not a big box store) We have a lumber store about 5 miles aways away that carries it and you will find it in your state as boat building happens in that state as well.

If I was making murals I would be using hydrotec .

I sue it in backing electric panels on a house or outside boxes on the home (say around electrical panels and utility trailer walls). It can take the wether and always stays flat. Cost well before wood went to costing more than gold recently  it was about 85$  to 100$ a sheet 4x8

The french cleat is still the best hanging method .

[Bill Kielb]

You can gallery wrap anything with a hardwood section to keep it stable, shadow box style. Sort of a picture frame with 1x2 wrapping but the wrapping is narrow stile facing out. If you can router a channel all around then 3/8” plywood or even 3/8” tile / cement board would be fine. The cement board being much more inert to moisture and matching the properties of your tile better.
Assuming your tile is 1/4” and mortar or glue 1/4” and maybe a 1/8” relief, route a 3/8” channel 5/8” back from one face  of the 1x2 to wrap around your backer board. You still have room in the back  (1/2”) for two supports horizontally to really stiffen this up in all directions. The top one could be a french cleat or any other picture hanging system you would like. 

If you glue the backer board continuously all around  and glue and attach your corners then this becomes very very warp resistant. Basically a picture frame. Stain seal and varnish the wood for a custom look or just paint it a suitable color.

Use exterior glue, tile board will be best for the mural, plywood is better than other woods though as the cross plies keep it more dimensionally stabile. Glue every joint.

It’s one idea that has worked for many years.

If you are not a fan of routing then 1/2”x 1/2” cleat is easy to glue and screw or pin nail 5/8” back infilled around the two cross members. If you have a pin nailer this is easy to glue and makeup quickly.

 

[Mark_H]

I would set the tile with acrylic fortified thinset on 1/4" hardiboard (unless it's exterior).  It will be heavy and need to be secured solidly.  I'm guessing this is more of a moveable work of art type thing rather than a permanent installation; otherwise it would be set directly on the wall.

 

[algebraist]

Wow, so much information...  Clearly I am out of my depth here, but seeing as I will be doing it anyway, so much appreciated!

First, I should have been clearer: Yes, inside, most definitely, and yes, it has to be movable.  Essentially, a ceramic painting.  (I guess "mural" has some outdoor connotation; it never occurred to me, but is an intriguing thought...  Sometime down the road perhaps.)

Second, no, I had no idea there were different grades of plywood...  And then so many other options.  I looked into cement board and hardie board, and apparently they are very heavy, which is a detriment -- I am really trying to keep the weight as low as possible.   Which makes Bill's suggestion most appealing.  It's been about two decades since I last used my router (and then only a few times ), but I wouldn't mind getting reacquainted.  And I will need something framing the outside of the work anyway, so it may as well do double duty and help keep it flat.  If that lets me use thinner plywood, that's a big win.

Finally, I will look into hydrotec -- better quality plywood should mean that a thinner sheet should do.

I have not yet started thinking about adhesives; I suspect I will be back with more questions when I do.

Thanks again, all, so much.

[Bill Kielb]

53 minutes ago, algebraist said:

Which makes Bill's suggestion most appealing.  It's been about two decades since I last used my router (and then only a few times ), but I wouldn't mind getting reacquainted.  And I will need something framing the outside of the work anyway, so it may as well do double duty and help keep it flat.  If that lets me use thinner plywood, that's a big win.

You can buy 1x2 prosumer hardwood such as poplar for the wrap and use the cleat method with 1/2 x 1/2 square lattice molding all the way around the inside back then just glue and screw your plywood to the cleat all the way around. No router needed except maybe to finish the front edge of the shadow box for practice.  3/8” plywood is pretty light but wrapped this way very warp resistant. Just use a tile mastic made for wood substrates if you use plywood.

[Mark C.]

The use of tile mastic on wood or thinset on hardie board is a key point-wood needs mastic cement board thinnest . Mastic is lighter