trellis above oven

[Robert Musa]

over the summer we built a trellis over the oven. we wanted the kind of excitement that comes only from having a large amount of combustible wood near the chimney! no, just kidding, we wanted something on which we could rest some temporary panels so we don't have to make pizzas in the rain this winter. also, its going to help keep more of the heat from the oven confined to the area around the oven when the winter comes. the middle panel of slats is removable to allow easy access to the top and to the chimney.

with respect to fire danger; i don't start the fire with lightweight material (like newspaper) and i've never seen a glowing ember escape from the chimney (which is topped with 2 layers of wire mesh). temperature at the top of the chimney is 475 (F) when the interior temp is over 1,000 (F).

[dmun]

I like your trellis

Your trellis looks good. Code says that you should have two inches between chimney and combustibles, and that the chimney should be 24 inches above anything within 10 feet. In this case you shouldn't need to worry about that until the next homeowner needs to get a c/o.

My town is full of chimneys with cedar shingles (which burn like gasoline) butted against exterior chimneys, so I don't know how important even that is.

My advice? don't use straw on top of the trellis to keep the heat in.

David

[Robert Musa]

i have more than the 2 inch clearance but lack the 24 inches. i've done a little more reading (isn't it amazing how building an oven increases your knowledge of so many areas like concrete shear strength and ignition points for wood) and found that the ignition point for wood is about 500 (F). however, there is this thing called "pyrolysis"... apparently if you expose wood to hot temps over a long period of time, its chemical composition changes and the ignition point can drop to 250 (F). given that i think i'm going to increase my separation space to 6 inches and keep an eye on it. it is so damp and cold here in the winter that it probably won't be a concern most of the time.

[james]

Robert,

We are going to have a similar situation at our demo kitchen in Healdsburg, and I am leaning toward simply going higher with a section of steel double wall (UL103HT to be exact) pipe. It won't cost much, and won't be too ugly (it should be hidden by the arbor).

Could you just stick a piece of chimney pipe up there to meet the 24" code.

James

[Robert Musa]

Robert,

We are going to have a similar situation at our demo kitchen in Healdsburg, and I am leaning toward simply going higher with a section of steel double wall (UL103HT to be exact) pipe. It won't cost much, and won't be too ugly (it should be hidden by the arbor).

Could you just stick a piece of chimney pipe up there to meet the 24" code.

James

adding height is not a problem. my vent arch is my problem child. the throat is too small (due to an error i made when pouring some repair mortar in that area). ultimately, i'm going to have to take the old arch out (or scoop it out from underneath) in order to accomodate a larger pipe and to enhance the draw. (but i'm dreading it.) it really works just fine, as is, if the wind isn't blowing briskly in the wrong direction. before redoing the vent, i have to tile the patio, build a fountain, pour another 500 feet of concrete in the back, rip out the kitchen wall... you know, the usual household tasks.

also, i was thinking of trying to come up with some sort of assisted, fan driven, exhaust pipe to enhance the draw and redirect the exhaust. it'll be a rube goldberg contraption...

[Robert Musa]

the trellis is also a great place to hang lighting. i installed 3 of those 7 watt malibu landscape lights on the inside of one of the 2 by 6 beams facing the oven and hooked them up to a timer. (1st picture below shot from rear of pizza oven; eva calls the area on the left my "mini-garage"). i didn't realize how much they helped until the timer shut off as i was making pizza. now i can cook without using a flashlight. i'm going to buy one more light. 21 watts shining directly on the landing makes a HUGE difference.