42" Corner Pompeii in Coastal Virginia

[Denamontini]

Shoot, I have another issue that needs to be voted on by the smart people reading this forum.


This is my outer arch (that will get covered up with decorative brick) I have no masonry training, so I made up a solution to having too much space, but not enough space and I turned a full sized brick sideways and angled it to made a keystone. It is only 2.25 inches deep. The clearance on the back was helpful in providing space for the chimney. There are hailing cracks on both sides of the keystone, (no where else) but it doesn't not budge when I yanked on it. (It was set about 18 hours ago)

Should I
1. Keep it as it is. Let it set for a few more days and just live with it.
2. Keep it and re-set it in new homebrew and reinforce the back with something.
3. Redesign the keystone spot all together.
4. do something else

Pics in the next post since they are on my phone and I am using a computer...

[Denamontini]

[MickyPizza]

I would redo it. Totally, no question. If you think THAT'S a ballache, It took me FOUR attempts to get an arch that I was either happy with or strong enough!

I did similar and that face on brick wasnt strong enough. I did two face to face and next day the oven side one simply fell out. There could be a lot of stresses pushing out against that brick. It looks a similar set up to how I did my vent etc. I wasn't happy about whether or not those long, vent siding bricks would hold for, so I mortared in some small cut firebricks between them and the dome for extra rigidity. Personally I would do a half brick there with hammered in brick wedges, like my pics 3 and 4.. That arch was one of the biggest problems I had. Difficult when you're making it up as you go along isnt it! good luck

EDIT - NOT like mine at all, this is actually your OUTER arch... Im tired!! haha

[Denamontini]

Update... I ran home after work determined to rip it all down and start again. When I got home, the mortar lines looked different and fuller. Still, I went at the mortar joint with an angle grinder and the keystone brick really was solidly stuck. I picked off the loose debris re-mortared where I grinded away. Then I cut and mortared in an identical keystone right behind the first one to provide more support. We are supposed to get a few days of rain, so I guess I’ll just wait it out and re-test it once the weather clears up.
I’m sure career masons cringe while reading posts like this. Sorry!

[Denamontini]

Happy Tuesday everyone! Here’s my progress. I fixed the outer arch and it’s solid! We’ve been doing some small curing fires with paper and small pieces of wood. We are going to put the insulation blankets on before we go any hotter. Still need to construct the chimney support.

[Denamontini]

What?!? This insulation blanket does not come shaped like a dome? I’m kidding. How precise do I have to be shaping it? This seems like a nightmare... any tips?

[Denamontini]

I’m thinking I’ll just take wedges out an make it smooth?

[cbailey]

It depends whether you are going for an igloo or enclosed. I opted for an igloo. My goal was to make the blanket layers as smooth as possible to facilitate a smooth render/stucco layer.

The stuff cuts pretty easily with a utility knife, and generally holds its shape. It's nasty stuff, so wear goggles, mask and long sleeves. I cut mine in wedges as you mention. The goal was to get a first layer with tight seams rather than over laps. Do the same with the second layer while staggering the seams, and perhaps a third layer. I covered mine with 3 layers of 1 inch blanket.

I finished the decorative arch on my oven before rendering the dome. The deco arch extends 2.5 inches beyond the firebrick outer arch. That provides a nice channel for snug fit for the blanket. The render forms a nice seal against the deco arch providing better insulation, and optimum protection of the insulation from water.

Cory

[UtahBeehiver]

Just like Cory said. Cut like orange wedges. Save the scrapes for your door.

[Denamontini]

Cory,
WOW!!! That looks/looked great!!! I’m reconsidering. I may hold off on the insulation until I get a little farther on the build. I still need to get the on chimney and complete the decorative arch. Did you put the stucco render straight on the insulation covered in chicken wire? It looks so smooth!

Russell,
I bought the 2” insulation blanket that you had posted about. (The good deal you had snagged a few rolls of... but I paid $100/roll) Anyhow, in your opinion, will the 2” insulation blanket be sufficient or should I also add the cement/vermiculite/perlite render. I was prepared to do it, but it is redundant?

Thanks again for all of the help!
Dena

[SableSprings]

Dena, 2" of ceramic batting is good although many would say to add some more because you can't over insulate. By using chicken wire and perlcrete/vermicrete over the insulation blanket, you are simply adding more insulation AND providing a more solid substrate for your final render/stucco on the outside.

Note that David S has gone to adding fibers to his outer render to help it stand alone (without a chicken wire base over the blanket). I still like the 8:1 or 10:1 insulating concrete (with some added clay for workability) over chicken wire that's holding the batting in place. Primarily because you can shape and smooth the dome exactly how you'd like it before adding the final waterproofing render/stucco layers. This is also my favorite method because you are securing the insulation batting in place during the curing process which may take a week or more. Then, when the last outer render layers are put in place, you are not having to deal with moisture still trying to escape through it and causing "cosmetic" problems...

[UtahBeehiver]

2" of ceramic fiber blanket plus a 2-3" of vcrete (6-8 to 1) should be great for multi day cooking. I made a curve shape trowel to help with keeping the vcrete smooth. Be sure to leave a vent at the apex of the dome to allow water vapor to migrate out. The breather vent will screw into a 1/2" NPT PVC or Brass or Galv Fitting. The breather vent are available at any car supply place for 5 bucks or so.

[cbailey]

Dena,

Sorry for the delay in getting back to you. I Just finished the second layer of stucco/render yesterday. To answer your question, I did apply the first (scratch) coat directly over the blanket/chicken wire. Oddly enough, I thought the first application went more smoothly than the second application! Go figure?

When you apply the render make sure to use a trowel with rounded edges. A rectangular trowel will gouge your work as you try to smooth it. Spray the render with water to keep it workable. Once it starts to set up you will want to scratch the surface so that the second coat will adhere better. I used an 18 inch scrap of 1x2 with four 6 penny box nails driven through it at about 1.5 inch separation. A stucco comb, if you will. Scratch about 1/8 inch deep. You don't want to go through the layer. You are just giving the second coat something extra to adhere to.

Use a garden sprayer to help moisten the scratch layer when you apply the second layer. As it starts to set up use a sponge float to smooth out the ridges and trowel marks and to provide a nice stucco look.

[cbailey]

I forgot to add...I covered my dome with blanket before I completed the decorative arch. I wanted to start my curing fires, and as Russell and others have pointed out you are less likely to incur cracks in your dome if the insulation is installed. The idea is that the dome brick heats more uniformly. Once I went through a curing cycle I completed the deco arch. I only applied one layer of 1" blanket on the entry arch. My reasoning for only using one layer of insulation is that I don't want to retain heat in the entry way. I was able to cut the insulation slightly larger than the space and wedge it in. The pressure from the deco arch and dome insulation was more than adequate to hold it in place.

[Denamontini]

Hi everyone. Long break... our refrigerator flooded our kitchen and well, we are distracted. This project needs to get done pronto. Here’s my progress...