Treehouse Pizza

[Giovanni Rossi]

I didn't use it , but the experienced builders on the Forum use:

3 parts sand
1 part Portland cement
1 part hydrated lime
1 part powdered clay

I recall david s recommending silica sand vs. river sand bc it has sharper granules. I just can't remember if that pertained to casting vs mortar. I'm sure he'll see this and clarify.

[RandyJ]

I am almost 100%positive that they have changed mortar since they made the videos. The color is completely different from what I have to what they show. I called Smith-sharpe fire brick supply and the have fire clay in stock for 19$ for a 50 # bag. I will continue to play with the supplied mortar but if I am not having good luck with it I will just switch to home brew. I know that works well .

What is the recipe for that again? I feel like it was 1,1,1,3 fire clay,Portland cement, hydrated lime, sand. Does that sound about right?

I have not been keeping exact time on this build so far . I was thinking of it but well i forgot to. I would guess i had 3 to 4hr doing the insulation and heat bank, 4or 5 hr doing the floor tiles and about 7hr on the dome so far. So ballpark 16hr so far. And probably about the same or a little more for the base. From my past experience I feel like this was the hardest part of just getting started and then everything just went together. . I am unsure if I will go all the way in brick or pour the key stone as is suggested. The castable didn't set very fast for me and I was kind of frustrated with it. I may have made it to wet and it dropped from the mid 60s' to about 40 that night so I am sure that didn't help.

Randy

[Giovanni Rossi]

Randy, Had to check my journal.

Started the bricks Oct 5
Had the problem on Row 5 on Oct 11 - 30 hrs at this point
Finished Row 8 Oct 24 - 65 hrs total at this point If you are planning to cast the keystone, that's all you would have left at this point.
I used brick the rest of the way and laid the keystone Nov 1 - 95 hrs total

No question having to prop each brick slowed me down. Plus, I was using an angle grinder to cut the bricks. And, most importantly, I just don't work that quickly. Masonry is not my strong suit. After row 3, I got into a routine of measuring out amounts of dry mix that would allow me to lay 5 full bricks at a time. I found the mortar would set too quickly if I tried to do more than that. So, there was a lot of time spent stopping and cleaning my mixing containers. Also, the daily temps were starting to drop, so that probably retarded the curing process a bit.

And, I'm retired and had no urgency other than wanting to get some insulation on and make some small fires to dry things out a bit before the first hard freeze.

Maybe Ben can give you some ideas about the mortar. He didn't seem to have a problem in his video. However, I believe they have changed mortars since that video was shot.

Hope this helps.

[RandyJ]

Hey Giovanni Rossi I just went back and reread that part. The slippage of bricks is something that concerns me. Maybe I am putting to much water in but this mortar doesn't seem as sticky as the home brew i made for the last oven. I am having thoughts of switching to that as it was stickier. I never had issues on the last oven even at almost the final row. I never used supports from what I remember and nothing moved.

So just as a question how long did your build take? This is where I was on my last oven at this point in time and it was ready by the 4th of July more or less so I am hoping I can make my deadline.

Randy

[Giovanni Rossi]

Randy, getting the consistency correct on the various cementitious products in the kit was one of my challenges. I wrote it off to inexperience. One comment on the speed of your build and your timeline. I went great guns on the first 4 rows and thought that it was going to be a piece of cake to finish. Then...row 5! Take a quick look at my build starting at post #47.

[RandyJ]

I got home a bit early today because of the training that I went to today. I managed to finish the first layer and then also completed the 2nd layer. I am torn trying to decide I'm I am making good progress or if this is taking longer than it should? My wife was like well how long is this going to take? I am trying to go fast but also try to keep a fair bit of quality too. I am not going for perfect because the time line goes up exponentially very quickly past here. I also covered the oven today as it is supposed to rain tonight. Not sure if I will be able to get anything done tomorrow as we have a trainer coming for our dog Peanut and my son has his ninja class. So I am guessing that I am not going to make any progress tomorrow. I also covered the oven tonight as it is supposed to rain. Not sure how much it would matter at this point because I have been stacking soaked brick and spreading water on the flat surfaces.

Randy

[RandyJ]

I managed to get some more work done on the oven this afternoon. I started by getting the layout nailed down and drawing the layout lines. This is not hard just a bit time consuming to make sure everything is correct and in place.

Once that was all completed I started soaking the bricks and mixed my first batch of mortar up. I started with the door arch and vent bricks. I think I may have had the mortar a bit wet but it worked out just fine. Once those were done I set to work on the first course of bricks. I got a bit more than half way around. I think the hardest thing is going to be getting the mix on the mortar correct so it is not to wet and not to dry either. Beyond that this feels like a giant lego set. If I had a full weekend I think I could knock off a major portion of the build in just a few days. As it is we have some kind of forman training tomorrow and I am really hoping for a half day on that so I can get after this some more tomorrow.

Randy

[RandyJ]

I managed to get some more work done this afternoon. First I found out about friends friends that was trying to get rid of some oak logs so of course I ran straight over and grabbed 2 full truck loads of loads and brought them home and neatly stacked the driveway. My neighbors going to try to get his friends splitter to split it all.

After that I mixed up a few more batches of mortar and finished setting the floor tiles. I had hoped to do that yesterday but with all the mothers day stuff going on I didn't have time or energy. I smoked a 16# brisket for my mother in law and that ate most of my spare time yesterday. Tomorrow I am hoping to start laying the dome bricks. It will be interesting to see how that goes. Wish me luck.

Randy

[RandyJ]

Well we were very busy today but I managed to get a little bit of work done this evening. I got a bit more then half the floor tiles in place and started getting rid of the forms from the concrete work.

Randy

[david s]

Many factors involved.
Type of brick used. High, medium or low duty.
Size of brick. The larger they are the more vulnerable.
Amount of use they get. Commercial ovens used daily are more vulnerable.
Rate of temperature increase and decrease. A slow rise is far safer.
Maximum temperature reached.
Only the bricks in the floor centre seem to suffer.

[Giovanni Rossi]

I'm not sure where I fall on the ability to replace a floor brick spectrum. I certainly understand the ease of removing one if it's not mortared, but what is the probability of needing to? I've read every post since early 2019 and don't recall anyone reporting having to do that. I seem to recall one of the long-term members stating that they were aware of only one. I guess it's possible it happens and guys don't bother to post.

Even if one of the floor tiles cracks, it shouldn't be that big of a deal. The only problematic issue I see would be if a tile is defective and the surface fails. Plus, unless it was located in an area that gets a lot of peel action, you could just leave it alone.

[david s]

It’s probably most likely to outlast your grandchildren.

[RandyJ]

david s this is one of the aspects of the kit that I am not fully on board with but am planning to follow it for the reasons that you listed. I really liked the possibility that I could potentially replace a brick if ever needed. The odds of this are very low though. I am sure there is some kind of solution if that ever needs to happen. The more likely thing could be that we would end up moving before that is ever a problem. I hope not to ever move again though as that was one of the worst experience and episodes of my life.

[david s]

You should follow the manufacturers instructions.
However, laying the floor bricks loose in a dry levelling mix allows for free expansion of individual bricks which receive uneven thermal expansion. It also has the advantage of making any brick replacement far easier. For these reasons it is generally a preferred method. Using mortar in the case of your build provides better contact and conduction with the castable layer.

[RandyJ]

Giovanni Rossi thanks for the vote of confidence. I hope I will be able to zoom through the build. I had hoped to be able to get some more done today but had to wait as the castable didn't set till this afternoon. I am trying to figure out what is a reasonable amount to hope yo get done in a afternoon or evening. Last time it took me more time to cut a row than it took to lay them. So once I get to the dome I am hoping to be able to do 2 or 3 rows per day when I get a chance to work. First thing I have to do though is get the floor down. Hopefully tomorrow I can make some good progress on that.

Randy