39" Pompei build in NH

[ML38]

Restarting this topic in proper forum


Building a 39" oven in New Hampshire. Even though it's only July, with my son's sports and everything else I have to do other than this oven, I'm already feeling up against Mother Nature and snow flying to finish. If you are familiar with weather around here, you'd understand that it can go from summer to winter and skip right over fall.

Oven is set back into a hill.
IT I made is easily adjustable so I can measure it for every course and maintain 19.5" and avoid a dome that has an extra inch in height.
Depressions in the front of the hearth are for granite pieces that will support my granite counter top that will extend 1 foot out. Last pic has the granite in place for a fit check.

Update on progress. Was on vacation and away from home so not a lot done. All the bricks cut for course #2 and I have almost half of them mortared (not shown in picture). I'm getting a little inconsistency in the angles so I think my jig for cutting needs to be either modified of completely re-done.

Couple questions before I get too far along and as I get closer to the arch

I've noticed a few gaps in between the bricks with no mortar. Should I not worry about them or go back and try to force as much mortar in as I can or if I do that will it just fall out later with heat and movement from the heat?

If I add a heat break between the inner arch and the vent/outer arch but not put a heat break in the floor bricks will it still serve a purpose? Basically it would put a break on the side/vertical portion of the arch and the actual vent opening and leaving the floor and landing bricks still in contact. Hopefully I've described this well enough for you to understand what I'm thinking.

Thanks
Marc

[ML38]

Progress Report:

I cleared the arch and have the bricks cut for course # 7. I'm using reclaimed firebrick so as I cut, they come out all different sizes becauces of the broken corners etc so it's a challenge to keep that joints offset.

The backside ofthe arch is pretty ugly. I had only enough arch bricks to do the arch and made a couple bad cuts so I recovered but it's not pretty. I'll get a picture after I remove the form. Just focused on completeing the dome and moving onto the entry/chimney.

Here are a couple pics. suggestions for improvement always welcome.

Maarc

[ML38]

Given how much work it was to get to this point, I'm curious what estimated percentage I will have completed (once the dome is closed) compared to what's left before I can cook a pizza?

It seems like it's much more time intensive with all the cuts and angles to this point and that the entry and flue (minus any finish work) and the insulation (I'm using 3 inches of CFB) should go comparitively fast? Am I out to lunch on this thought?

Just wondering
Thanks
Marc

[SableSprings]

I personally felt things started going much quicker once I could see the dome closing in a few chains. The landing/oven entry and smoke collection/flue entry aren't all that bad, especially since most are getting pretty comfortable with cutting and mortaring at this point. I also was a little discouraged because my oven wasn't as "pretty" inside as other builds on the forum...but you know what? Nobody notices those things when they're at a party and eating pizza being "pulled from the fire".

Marc, I think your oven is looking great! Filling those little gaps between some of your earlier laid dome bricks really doesn't matter...try to be more conscious of having adequate mortar when laying the next bricks...but it's not really important enough to go back and stress about some minor joint gaps. The heat breaks are nice, but unless you are concerned about having great cooking temps 4-5 days after a firing, they really don't "make or break" an oven's usefulness and value. I bet you'll have plenty of valuable cooking time after a firing to meet all your expectations. Put in heat breaks as are convenient for your workflow and time. Yes, there will be heat loss without all the breaks...but there is no perfect heat retention solution. Kind of like distilling water, doesn't take much to create 99% pure water but the cost skyrockets if you want to get that last percent

After you close and set up the flue, you can begin the curing process. You certainly can put on the insulation batts during the curing process. Lots of discussion here on whether to insulate then cure or cure then insulate. IMHO, as long as the curing process is slow and steady, both methods produce the same result. Since you are in the Northeast, you need to think about keeping the dome dry when it rains. Even after you have done a stucco or rendered coating over the dry insulated dome, water will seep into the base board ceramic quite easily if you let any water pool or stand around the dome base edges. Also, many builds have included a simple vapor vent at the top of the dome. This vent allows moisture to escape after the dome has been enclosed with stucco or a waterproof render.

[ML38]

Mike,

Thanks for the feedback. It's nice to be reassured that I'm heading down an acceptable path. I plan on a vent because I expect it will be near impossible to keep the water out. I'm pretty happy with the way it's gone so far considering my lack of experience. By coincidence, your build has been one I've looked at a lot. Not only do I have reclaimed firebrick, but I have reclaimed red brick from a 150 yr old farmhouse around the corner from me. much of it was used in a warming oven. I want to use it to build the buttress on the sides of my entry, similar to yours and possibly the chimney if I have enough. My plans have changed so much as I go that who knows if that will be where I end up. Fun journey for sure.

Thanks for the advice

Marc

[ML38]

Course 8 is complete and by doing the math it looks like I'll only need course 9 and 10 before I'm ready for the keystone! That's one less than the spreadsheet indicated and less work is always good.

I'm happy with the results so far using the reclaimed bricks. A couple lined up joints that I couldn't avoid without recutting bricks. I have a large piece that I grabbed the I can cut for the keystone that is 6 or so inches square with a slight curve on one corner. No idea what it was used for but it will make a nice one piece keystone if I can get it cut with my 10" saw. I'll try to get a pic before and after.

Is there a badge of honor I can claim if I can complete the entire dome with only the IT and no form? Course 8 went pretty well with one stick to hold up brick 1 while I used the IT for all the others until I cam back around in inserted the keystone for that course. Only 2 more to go. I think it's possible.

Latest dome pic:

[SableSprings]

Looks fabulous Marc! I am impressed by all the work you've done using these smaller reclaimed pieces. The work you've done is even more amazing when seeing how few joints got lined up. Anxious to see your single piece keystone placed. Sorry, no badge of honor for "IT only builds" that I have been able to locate...but everything you cook in the oven will put a medal on your cap and a smile on your face

[ML38]

Looks fabulous Marc! I am impressed by all the work you've done using these smaller reclaimed pieces. The work you've done is even more amazing when seeing how few joints got lined up. Anxious to see your single piece keystone placed. Sorry, no badge of honor for "IT only builds" that I have been able to locate...but everything you cook in the oven will put a medal on your cap and a smile on your face

Mike,

It's getting much harder to not line up the joints now that the bricks are getting so small but I'd think that would be the case for everyone.

Maybe someone should start a thread for "IT only" builds! It could be like those bars that have 100 beers on tap you get your name on a plaque after you have tried them all.
I'm going to try but I also pulled out the exercise ball just in case.

[shanxk8]

I recall someone posted about using metal hooks with string & bricks that hang back out the outside of the oven to hold thngs in place. (I think it was in Africa, there were pictures too)
i'm gonna have to remember to try that as I'm hoping to have an :"IT only" build.

So i'll second the idea for an "IT only" builds thread (assuming i succeed )

[UtahBeehiver]

The hook and counter weight concept was done by a couple builders on the forum. It was done to keep gravity from taking over and the bricks sliding to the floor not so much to keep a round shape. The builders used a similar set up as shown in the attached pic.

[JRPizza]

My dome was IT only. If you get your mortar right and your IT can move free from the bricks without pushing or dislodging them it is relatively easy. If I remember right I was using dry(ish) bricks and very wet mortar, and was able to set a brick and move on in less than a minute. I think I found if I waited too long there was a tenancy for the bricks to break loose. I clamped bricks to my IT for the lower courses but then figured out that clamping was not needed with proper technique.

[shanxk8]

That's the picture, thanks Russell!
Did those that used it find it worthwhile?

[ML38]

Progress Report:

Course 9 completed and still an "IT Only" build. Used JRPizza's method of dryish brick and wet mortar for the first couple and then wet the bricks a bit more after that. It went really well, Thanks JRPIzza!

I've cut all the bricks for the last course and hope to get the dome closed on Saturday. After that I'll have to pour a small slab to level out hearth with oven floor and secure the granite 'arms' that will hold my counter before I start the entry and vent. I can see a small light at the end of the tunnel.

[ML38]

Since I'm on the verge of moving on to vent/chimney and landing build and I still have plenty of ingredients for the homebrew, two questions:

1. When is it OK to move to standard mortar? My plan is for clay flue and masonry surround so I'll need buttress on both sides. Use for vent/flue and standard mortar for buttress and chimney?
2. What recipe to use for the standard mortar so I can use what I have left of Portland/Lime/masonry sand? I stumbled onto the Tscar 3:1:1:1 thread today and don't want to stir that up again so just looking for an acceptable mortar mix for the buttress and chimney.

Thanks
Marc

[SableSprings]

There are several mortar mixes that you can buy (or make yourself). I purchased and used Type S for my outside brick oven facade, outer arch, and chimney work. Type S mortar is 9:1:2 (sand:lime:cement) and has great compression strength and the mix ration results in a quite bit of flexibility/tensile strength (earthquakes, soil movement, wind...) as well as being able to stand up to pretty good heat levels.

Since you're looking at parts of the oven that will/could get a bit hot (not pizza temps, but warmer than a sunny day ), I'd make and use this mix for the rest of your work. You can also use a 6:1:1 (Type N) mix which is fairly standard for outside, medium strength brickwork. (That's sand, lime, cement - 6:1:1) and I suspect it would be fine for the job.

I know we have several folks on the forum with more mortar knowledge than me, so I hope they'll chime in if I'm off base on this.