Keystone Size

[deejayoh]

Re: Keystone Size

I think you probably should have some air space for circulation purposes.

When you start messing with the design, you may find as I did that the combo of acceptable clearance for the eaves + a roof pitch that doesn't look odd will dictate your flue height.

but you are a long way from needing to decide!

Here's my housing under construction for reference, showing dome clearance, pitch, and height.

[K79]

Re: Keystone Size

The ends of your eaves are about 5 1/2 feet high in that design. Not sure how tall you are, but I personally wanted the eaves higher than my head. I had to go with 42" of pipe and that was just enough to get ~6'2" of clearance for the eaves. But I have never bumped my head!

Is there some sort of height requirement though between the top of the insulation around the dome and the top of the roof. The FB plans say 4" but I'm not sure if this is just a recommendation or requirement for some safety reason. I'll be adjusting my roof pitch some thanks to your comment.

[deejayoh]

Re: Keystone Size

The ends of your eaves are about 5 1/2 feet high in that design. Not sure how tall you are, but I personally wanted the eaves higher than my head. I had to go with 42" of pipe and that was just enough to get ~6'2" of clearance for the eaves. But I have never bumped my head!

[K79]

Re: Keystone Size

I was planning on doing a full enclosure? It should work with that as well. What do I need for clearance over the top of the roof? I have almost 2'.

[deejayoh]

Re: Keystone Size

I have 235sqin so if I go somewhere between 35 and 40 sqin for my vent opening I should be ok.

What are your thoughts on the arch itself? I was thinking of a 36" stack... too tall? I'ld love to be able to do it a little smaller.

Are you doing an igloo or a doghouse? 36" length works fine for draw with an 8" round on a ~40 inch oven (In my experience) but it will be too short for a doghouse (won't clear the roof eaves). Probably fine with an igloo.

[K79]

Re: Keystone Size

Original poster, the owner of the thread.

Post away !!

[Tscarborough]

Re: Keystone Size

Original poster, the owner of the thread.

[kbartman]

Re: Keystone Size

Thanks,
Tscarborough, OP?

[Tscarborough]

Re: Keystone Size

Up to the OP on the highjacking, some threads wander all over. That size should be OK, though.

[kbartman]

Re: Keystone Size

I limited to 8" on my depth and the 8" X 17" was one of standard flues stocked at the brick yard,the other were to small or to big. I thought it would work. Now I'm unsure

The other day Utahbeehiver was worried about highjacking someone's thread to answer one of my questions. Is this consider highjacking? Dont want to affend anyone. I need all the help I can get.

Thanks

[Tscarborough]

Re: Keystone Size

Basically, the draw would be twice an 8x8, the floor size doesn't matter, what is the inner arch opening size?

They make the flashing for the double pipe penetration, the masonry chase is done with step flashing. In either case you probably want to offset it so that it penetrates a flat plane not the ridge. In my case I made it a shed roof for more protection in front and I didn't want to offset the flues.

[K79]

Re: Keystone Size

Tscarborough,
Hope im note butting in I'm new to the furum. (More is better to a limit.) What is that limit? I'm thinking of using 8 x 17 flue on a 40 inch oven.
K79 been reading your build looks good.

That seems like a lot. It'll be interesting to see what everyone thinks.

[kbartman]

Re: Keystone Size

Square/rectangular flues are measured o.d., while round ones are measured i.d., FYI.

8x8 is a common size for clay flue liners, with 30.58 SqIn of draw: 6.25 (i.d.)/2 gives a radius of 3.12, 3.1416x(3.12x3.12)=30.58. When calculating draw you draw the largest circle(s) that will fit in the area and use that dimension. The area of the flue should be around 15% of the size of the inner opening, and more is better up to a limit.

(the floor size doesn't really matter for draw)

Tscarborough,
Hope im note butting in I'm new to the furum. (More is better to a limit.) What is that limit? I'm thinking of using 8 x 17 flue on a 40 inch oven.
K79 been reading your build looks good.

[K79]

Re: Keystone Size

I do not understand the difference between piercing the roof with double wall pipe or masonry?

I don't either... this is all new to me.

[Tscarborough]

Re: Keystone Size

I do not understand the difference between piercing the roof with double wall pipe or masonry?