Tile / Mosaic finish for dome

[Bloggorus]

Hi guys,

I'm putting the final layers of render on my arch oven.

I thought I could use tiling or some kind of water proof mosaic finish to kill two birds with one stone: a final layer of protection that's good looking AND functional.

A place near us sells broken tiles at half of retail price and I figured the rustic look was appropriate given that most of my oven is made of recycled materials.

Is there any reason why a standard tile finish could not work as well as it does in bathrooms for keeping out moisture?

Ideally i'd like a grout and adhesive which does waterproofing AND thermal insulation, but as far as i know that would be hideously expensive and/or require specialist materials.

[Bloggorus]

Re: Tile / Mosaic finish for dome

Went down to a local tiling place to look for possible solutions. Meshed mosaic tiles are INCREDIBLY expensive, looking at anywhere from $200 to $500 a square meter.

In the end the guy took us aside and said to head to theh local hardware, pick up ingredients for our own render mix and a few backs of river pebbles. Glue the pebbles all over the oven with render than finish it with a waterproofing coat. Problem solved.

I'll post pictures of the final finish.

[neophyteguy]

Re: Tile / Mosaic finish for dome

Hey mate, what type of "waterproofing coat" are you considering? I'm doing something very similar down in Apollo Bay and can't quite get my head around the waterproofing aspect.

I'm considering using this to attach the rocks....Selleys Liquid Nails Landscape - Construction Adhesive | Selleys Australia and then grouting it.

BUT, still not sure what grout will give me the best weather protection or if I need to seal the render before I glue on the rocks.

Can't wait to hear what your thinking...

[david s]

Re: Tile / Mosaic finish for dome

For mosaic tiles on the outer decorative arch I recommend applying a tile sealer to the surface first and then glue the tiles on with a quality outdoor acrylic adhesive. Only use black grout because you will never get any smoke staining off a light coloured grout. Also use only glossy tiles, not matt, for the same reason.

[Bloggorus]

Re: Tile / Mosaic finish for dome

Still a work in progress, weather and Cup day set things back a little

In the end we are going with the classic smashed tiles mosaic. The pebbles idea was nice but it didn't fit the site aesthetically.

As far as adhesives go, we arent using anything flash. We will lay te mosaic into a homemade concrete render, a mix of concrete, lime and fine pastering sand. Now that you mention it it might be worthwhile mixing some kind of adhesive through the render, like PVC or epoxy.

Once the mosaic is down I will grout the whole thing with a sludgier version of my render and see how it holds up to the heat and exposure. My dome doesn't get too hot except for huge burns, so fingers crossed. I don't mind paying more for special grout down the track if need be, so we'll see what happens.

I will seal it with standard tile sealant they use in bathrooms and see how that holds up too, but I don't expect it to last forever.

It's not so much supposed to be waterproof, more like water resistant. From what I've read on these forums making your oven totally sealed is a recipe for disaster. If water ever does get in it cant escape when heated and your dome cracks, or worse explodes.

With tiles, I figure that less moisture will get through, but there's also room for it to come out when you eventually fire it up after a big storm.

[dottavio]

Re: Tile / Mosaic finish for dome

I am thinking about a mosaic tile finish for the same reasons. I have not started yet, but the tile stores I have visited have stressed using the correct products for excterior use. Especially if you live in freeze/thaw. The grout must also resist UV rays. IMHO a few more dollars is worth all the time and effort to get to this point.

I am debating wether or not to apply a waterproof membrane over the perlcrete. They sell brush on products for this purpose, but the point about letting it breath confuses me. I figure that stopping the water is the first priority, but worry about a failure in a small hairline crack.

Perhaps I'll just cover with a tarp during heavy rains and the off season.

Doug O

[Bloggorus]

Re: Tile / Mosaic finish for dome

I am thinking about a mosaic tile finish for the same reasons. I have not started yet, but the tile stores I have visited have stressed using the correct products for excterior use. Especially if you live in freeze/thaw. The grout must also resist UV rays. IMHO a few more dollars is worth all the time and effort to get to this point.

I think it depends on the finish you want for your dome; a perfect tiling job would be nice, but I imagine it would take too much time and money to maintain and do right for me to bother.

Concrete 'grout' between the tiles won't have that clean tiled finish that some might like. In my opening post i mentioned the holy grail of tiling grout, something that is waterproof, weatherprpoof and heat proof, but I didnt find any product within my budget or expertise. In the end i'm going low-tech.

I am debating wether or not to apply a waterproof membrane over the perlcrete. They sell brush on products for this purpose, but the point about letting it breath confuses me. I figure that stopping the water is the first priority, but worry about a failure in a small hairline crack.

I would STRONGLY recommend not putting a waterproof membrane next to percrete. It sucks up moisture like nothing else, and if ANY water gets through that membrane it will flash to steam under pressure and ruin your dome as soon as you fire it up. Like you said, a single hairline crack and that waterproof layer might as well not be there, and only pressurises and funnels the steam, turning it into a geyser inside your dome which will cuts it's way out.

'Letting it breathe' is maintaining the ability to drive out residual moisture with curing fires. Locking out moisture also locks it in, and doing so can be dangerous for the same reason that waterproofing concrete and rammed earth walls can be dangerous. The water has nowhere to go.

At the moment my dome consists of bricks, then a layer of thin lime render, then a thick layer of perlcrete for insulation, then a few more layers of render.

The outer layers were applied slowly over time- thorough curing, then a layer, let it dry for a week then another thorough curing. I went through this process several times over the last two months, usually taking the opportunity to do a little cooking If it rained, that meant more curing, so good weather helped.

My dome is really as 'waterproof' as it needs to be. The concrete is still slightly porous, but the water doesnt seep right down to the perlite. ( which is absolutely vital for when you fire it up after a winter.)

I wanted to use tiles for a) the finish and b) the little extra protection it might provide, not to create a hermetic barrier.

Perhaps I'll just cover with a tarp during heavy rains and the off season.

I will probably do the same, although taking the time to bring the oven out of hibernation slowly should prevent any accidents.

[Tscarborough]

Re: Tile / Mosaic finish for dome

To understand "waterproofing", you have to understand the difference between liquid water and water vapor. The goal of waterproofing is to shed liquid water, but allow water vapor to transit the material. A high lime or high marble plaster will allow the transmission of water vapor while being resistant to liquid water, while adding latex or acrylic will inhibit both.