36" Pompeii in DC

[rsandler]

Re: 36" Pompeii in DC

I'm starting to think about tiling the exterior of my dome. I was originally thinking of doing a mosaic design, with some trepidation as I have very little artistic talent. Then I happened across some very nice looking slate tile while wandering through my local home depot. Mosaic artistry may be beyond me, but fitting rectangles onto a hemisphere is more within my power. The only question is how to put them on, and whether they will stand up to the weather.

In principle, slate ought to be impermeable enough to be frost resistant. In practice, many slate tiles seem to be rather more absorbant, I guess because they are actually shale or quartzite? I picked up a 4-pack of tiles this weekend and tested them by soaking in a pan of water. One tile absorbed less than .2% of its weight in water. Another, which seemed to have pocked areas on the underside, absorbed more like 1-1.2%. The standard for exterior tile seems to be .3-1%. I'm thinking this may be close enough. Worst case scenario, they're cheap, and easy to replace if one pops off.

Questions: Would it be possible and desirable to lay the slate tiles in an overlapping manner, much like slate shingles? See attached pictures.

Also, I have never worked with thinset before. Do I need to make the surface flatter before tiling (e.g., by applying another coat of stucco?). How big of a tile can I reasonably apply? (I'm fairly sure that the 6" tiles in the picture would be too large).

Still waiting for my steel to arrive, and hoping the existing door doesn't crumble or burst into flames in the meanwhile...

[Gulf]

Re: 36" Pompeii in DC

RSandler,
The 6" tiles look great. I am not sure about overlapping them, maybe someone else can comment. It would be interesting to see it done. But even if they are, I think that 6" is too large for the size of your dome. The finished exterior of my 44" was able to accept a 2 3/8" X 4" brick splits with a little extra buttering on the bricks near the head joints.
I don't understand "flattening out"? The dome will be a compound curve. Maximizing the cuts from the stock that is used is what most people try to do. 6" X 6" will yield 2" X 3" tiles (minus the saw cuts). Note: your tiles may already be a little less that 6" X 6". Again, I'm not sure about the overlapping but, I think they would look great, and would mimic brick. That is, if they were laid to look like brick. You can still use the tile method on the compound curve. I used Old Chicago floor splits. But, I used the tile method with spacers to install them.
You can use a sealer on the joints, if you are wanting to make it as waterproof as possible. That is, if you are intending on installing some type of vent at the apex. The copper chapiter makes me think that it is being considered. If you overlap, I would cut the stock to 3" X 3".

[rsandler]

Re: 36" Pompeii in DC

Gulf,

Thanks for the comment. The slate tiles do look pretty--just have to hope they don't chip, spall and pop off in the winter here.

Re: flatter. I used the wrong word there, but I think you answered my question anyway. I didn't mean flatter but rather "smoother". Unlike more talented builder like yourself, my render coat is a little craggy in places, with lips of maybe 1/8" at most. But, like you say, the dome is a compound curve, and if little 1/8" lips will cause a problem, the whole endeavor is probably doomed. Given that you and CobblerDave and others have pulled off the brick/tile facing approach, it will likely work fine for me, crags and all. Plus or minus my own clutzyness, that is

-Ryan

[rsandler]

Re: 36" Pompeii in DC

Re-built my door last week. Still would be nicer to have a 4 inch thick, stainless door like Chip, but I think this will hold up for awhile.

The construction is now: Wood, steel, cement board (to allow me to screw into the wood), insulation, then more steel. Also stained and put a coat of polyurethane on the wood, to make it easier to clean it when it gets soot on it (also makes the soot less noticeable )

The picture of the back shows some rust forming on the outer piece of steel, I think resulting from the load of firewood that I dried out following the door's inaugural use. Should I be worried about this, and try to buff it off with steel wool, or leave it be?

Other question, for Gulf or others: Do you think that 4"x4" tiles would work on the dome? Home depot sells those same slate tiles in a package of 9 4"x4" tiles. It costs about $0.75 more per square foot, but it might be worth it to avoid having to make hundreds of cuts with the brick saw.

[Gulf]

Re: 36" Pompeii in DC

Ryan,
The rebuild on the door looks great! It ought to last you a long while.

Original quote by rsandler:........Other question, for Gulf or others: Do you think that 4"x4" tiles would work on the dome? Home depot sells those same slate tiles in a package of 9 4"x4" tiles. It costs about $0.75 more per square foot, but it might be worth it to avoid having to make hundreds of cuts with the brick saw.

They should work alright, as far as the curve of the dome is concerned. However, the extra height of the tile is going to add a lot to the "upside down v's" . You will probably be trimming your tiles to accommodate this even if you use the smaller tiles cut from larger stock.

I used a 3/8" X 3/8" notched trial to apply the thin-set to the back of each brick. I buttered them a little heaver at the head joints. You will probably need to do that for the bed joints as well, if you go with 4" X 4" tiles.

Decisions, decisions......

[mrchipster]

Re: 36" Pompeii in DC

Should I be worried about this, and try to buff it off with steel wool, or leave it be?

Just leave it be, It will hold up for a long time and buffing it off will remove more material than a little oxidation can do.

Keep your eyes open for some stainless some time soon some will almost fall in you lap. Like a neighbor giving away his stainless BBQ that has a bad burner or something similar.

BTW Nice rebuild.

Chip

[rsandler]

Re: 36" Pompeii in DC

Started placing my slate tiles on the oven a couple of weeks ago. It's slow going, especially because it's been too hot here to work after noon or so. Still, I think this is going to turn out pretty nice. These pictures were taken before I started work yesterday; I got another couple of rows on before stopping for the weekend.

[rsandler]

Re: 36" Pompeii in DC

Work continues on the tiling. Another couple of rows and I will get above the arch and vent, although that is distinctly less of a boon on the outside of the dome than it was on the inside.

As I realized I was approaching the vent, I decided it was time to do something about my flue. The flue has never drawn particularly well (or rather, no better than the vent with no flue on top). Having a ~7.75"x7.75" flue on top of a 5"x6" vent will do that. Further, a couple of months ago the flue tile cracked all along one side. Given the the problems I've had, I decided to climb up on my countertop and see what would happen if I just gave it a little tug. Turns out, it popped right off; the mortar barely held it on :P.

So now I need a new chimney/flue, primarily for aesthetic reasons--the oven looks kind of funny with just a stump of a chimney. Plus I need something to attach a rain cap to...

I'm thinking of taking the handful of leftover firebricks from the build along with the bit of leftover homebrew and just extending the brick chimney by a foot or so.

Any reason this wouldn't work? My current chimney stub is just over an inch thick back and front (a brick cut in half lengthwise). Will I have similar problems with cracking, or will the mortar allow for a bit of expansion? I don't have space to insulate the chimney, unfortunately.

Pictures of my newly removed arch, plus progress on the tiles.

[mrchipster]

Re: 36" Pompeii in DC

What about creating a decorative arch on the outside of your current arch that way you would have a landing location for your flue with full size bricks, in the back - oven side, you could easily build up support for full size brick. That way you could do a chimney surround that looks real nice.

BTW... I like the slate tiles.

[rsandler]

Re: 36" Pompeii in DC

What about creating a decorative arch on the outside of your current arch that way you would have a landing location for your flue with full size bricks, in the back - oven side, you could easily build up support for full size brick. That way you could do a chimney surround that looks real nice.

So, are you thinking then that a half-brick thickness chimney won't hold up? Or that a full brick chimney would look better. I've thought about doing a decorative arch to give more room for a chimney, (and also maybe to catch smoke a bit better), but I'm not sure if its worth taking the time. I want to figure out the new chimney/flue before I put tiles on the dome near the vent, and I want to get on with the tiling job. But, I don't want a cracked chimney either!

BTW... I like the slate tiles.

Thanks!

[rsandler]

Re: 36" Pompeii in DC

Bunch of work in the last few weeks. Being convinced by Chip (and others) that a thin brick chimney won't work and unconvinced that a SS flue would work/look good/be worth the money, I went ahead and built a decorative brick arch to support a chimney.

Decided on a 6" round clay flue to go inside the chimney surround. Testing it out Saturday evening, it seemed like I was getting better draw from the 12" tall 6" flue than I ever got out of the larger 24" flue. I will add at least one more 12" tile as the chimney gets built.

Also made headway on the tiles, putting the last tiles on Saturday. I still need to clean bits of thinset out of the grout lines and apply grout. A task for this weekend, I think.

Bunch of pics of the oven attached. Isn't it looking pretty with it's new coat?

[mrchipster]

Re: 36" Pompeii in DC

Coming along nicely, love the tile work. And I am glad the flue draws better.

[cobblerdave]

Re: 36" Pompeii in DC

Gudday
Great work on the tiles .....they look smart! What's that at the top of the dome a vent cover?
Regards dave

[rsandler]

Re: 36" Pompeii in DC

Gudday
What's that at the top of the dome a vent cover?
Regards dave

A vent cover to be, rather. It isn't actually attached yet, and I haven't even drilled the vent yet. Plan is to grout first.

[cobblerdave]

Re: 36" Pompeii in DC

A vent cover to be, rather. It isn't actually attached yet, and I haven't even drilled the vent yet. Plan is to grout first.

Gudday
The vents a good idea.
You might consider using colour grout to match your "red brickwork" might tie the two together, but both look good anyway!
Regards dave