42" In South GA

[edonovan]

procrastination is a son of gun!! Finally got over this hump, feel good about it! Couple questions, 1) anyone have insight on the insblock vs perlite board? And measuring across me floor I do get 42 1/4”, most likely little discrepancies in my cutting the brick. 2) does this matter right now or I can correct this once going up? 3) type n on lime good? From what I am finding it comes into “stickiness”?

[mongota]

Can't comment on the insulation, I'll leave that to those that know.

I'll pass on what I recall regarding lime, and again, there are others that may know better, they may post afterwards:

Lime, I'd recommend you look for Type S instead of that Type N in the photo.
While looking, don't confuse MORTAR types S and N with LIME types S and N. Twenty-six letters to choose from, and they had to pick the same letters to designate?

Types S and N differ in the percentages of magnesium carbonate and calcium carbonate in the two limes. My remembrance is that essentially, N requires additional hydration by the user before using it in mortar.

I am not a mason, so take this for what it's worth. Free internet advice, lol. But I have been doing concrete and mortar work on some way shape or form for longer than I'd care to admit. Type S out of the bag is ready to use in mortar. Type N, personally I've never used it over the years. But my understanding is that If you do use it, you should allow it to slake for a day or two, and even then, it's sort of a crap shoot as to handling/plasticity and end strength, etc.

Example of Type S: https://www.homedepot.com/p/Chemical...5040/202616008

[edonovan]

Thanks for the information mongota on the Lime... hoping someone has some insight on the insulation or I may have to just make my best educated guess. I know some have used Insblock-19, not sure about the Perlite.

[mongota]

Fellow builders, especially the moderators, are usually quick to jump in. I'd venture since no one offered info on Perlite board, they're possibly not familiar with the product? Like you, I do know Insblock-19 has been used often. I almost used it myself. Without validation from those in the know for the Perlite product, I'd go with Insblock. Sorry I can't be of more assistance.

[UtahBeehiver]

The specs on a specific perlite board is needed to give a comment. I saw one posted earlier this year and it appear to be a good substitute and was water resistance as well.

[NCMan]

The specs on a specific perlite board is needed to give a comment. I saw one posted earlier this year and it appear to be a good substitute and was water resistance as well.

Yes. I'd love to see it, also.

[Gulf]

edonovan attached the perlite board spec sheet here in post #28 of this thread.

[UtahBeehiver]

Gulf reminded me that the PDFs were posted earlier and I was out of pocket then. So here is my take, either product has plusses and negatives to CaSi( ieThermoGold 12) or AlSi (Forno Bravo)

Insblok 19, Pros 1900 F service, K .55, Cons low side of compressibility 38 psi at 10% vs 100 psi at 5% of CaSi, (meaning kind of soft to support the oven, recommend 70 psi @ 5%), Perlite Sproule 1200, might be water resistance, although this particular brand does not say so, Good compression, 80 psi at 5% , Cons higher K value 0.74 (but still good), lower service temp at 1200 F but you will not see this temp on the bottom side of floor brick.

[edonovan]

UtahBeehiver Thank you so much for the insight, I’m thinking the perlite is just that edge better as far as obtaining locally and not having to get into shipping fees. Waterproof isn’t too big for me (added bonus if it was) doing weep holes and tile not mater what anyways.
Trying to read and understand this K value.... .55 vs .75, the perlite won’t “hold” the heat as long? So I may not get long cooks out of a firing? Or am I splitting hairs?
thanks again everyone, happy thanksgiving weekend!

[UtahBeehiver]

splitting hairs...

[edonovan]

UtahBeehiver thanks for the voice of reason....with that being said, I am purchasing that this week and remember reading someones words on here about "not wanting to end up with a really expensive fireplace". The place I am getting this from has either 2" thick or 2 1/2". Is 1 layer of 2.5" enough to retain the heat and have a couple days of cooking or should I go with 2 x 2" thick?

[mongota]

edonovan [QUOTE=edonovan;n433628][USER="19129"The place I am getting this from has either 2" thick or 2 1/2". Is 1 layer of 2.5" enough to retain the heat and have a couple days of cooking or should I go with 2 x 2" thick? [/QUOTE]


It's tough, because our individual needs in oven performance and the environment they preform in can be so variable.

I can tell you that the only day I regretted going with two 2" layers for a total thickness of 4" of insulation board under the floor was the day I bought the insulation. Cha-ching!

In the several hundred fires and the multi-day cooks I've done since? Not one day of regret.

[edonovan]

Christmas...check....New years....check...snowboard trip...check!
Now that all of that is behind me time to get moving on this thing! Got my weep holes drilled today and first layer of Perlite board cut. Need to grab another box to give me the 4” of insulation I want to do. Upon measuring that will give me a cooking floor height at 41” which is almost perfect for limiting bending down for fire/pizza check. Also, had my IT built with a caster and read more on the pitfalls of the caster. Went on a fork bolt search and found this guy...question, is 1 3/4” off the floor too much for my pivot point? Will I have more issues with this then the caster or just adjust my IT according to the spreadsheet?
thanks in advance everyone

[edonovan]

This insulation sure is brittle! Got another box of perlite for my 4” and did a rough layout with my floor, need to push it back a bit. Wondering if I should set back my entrance about 3/8 or more to account for any decorative tile to finish off my base. A tile mortar should adhere to the perlite right? Also considering cutting my entry a bit after where my inner arch will sit, as I have read people just having running bricks and don’t have to have a herringbone. Hope to be going upwards soon, more photos to follow.

[UtahBeehiver]

So you are a knuckle dragger huh, where did you normally ride? Back to business. The pivot point off the floor elevation will increase the dome radius incrementally with the dome apex being the largest increase. I cannot see it your IT is adjustable or not. You can correct each course to the correct radius with an adjustable IT. This is important if you do a tapered inner arch. Do not move the inner arch in to adjust for outer tiles, this affects how the dome ties into the inner arch. Adjust the length of the vent chamber bricks if you need tile space. You will probably need a fairly thick mortar bed against the insulation to attach the thinset the tiles to (ie 1" or so) because the mortar bed will not generally bond to the insulation very well.