Entrance porch depth - is it important?

[bigdavenorcott]

I tried to draw a pic to explain this question, but it was so awful I'll just describe it instead

I know there are rations for height of entrance etc - but is there a similar calculation for how deep an entranceway has to be to a WFO? Apologies if I'm not using the right terms, but I mean the exterior arch & porch, in the top of which is the flue. 

I've seen these nearly always as at least a brick-and-a-half deep, with the half brick depth left as a flue at the rear top of the porch - mine however is very tight for space, and if possible I'd like to make it one brick only (still with a half brick flue gap). This would mean that after insulating the outside & rendering that little or no porch would still poke out of the structure, but that I can live with, if it doesn't make any difference to the way the oven works.

Hope that makes sense - any comments gratefully received! 

[cannyfradock]

Dave

There's no such thing as a silly question when building your own Wood-fired oven......and your question makes perfect sense. Yes...correct, most entrance arches have a brick and a half purely for the ease of creating an opening large enough to get a decent "draw" from the oven.

This can still be done with a one brick entrance arch. It just means that the bricks....or brick slivers at the front and back of the opening need to be quite thin. Lets say that you have a 6 brick arch.....the 2 bricks left and right will be full bricks but the center 2 bricks......front and back need to be cut with an angle grinder just 2" wide. This is a bit fiddly to do but as long as you fully fill the mortar joints between each brick, the arch will still perform.....as an arch. It has to as both front and back will have a continuous bricks and mortar construction. This should leave a 5......but more like a 4 and a half inch gap. It should however be about 6 1/2 " wide so if you play about with the chimney/flue a bit and make sure the underside is sealed...... you should have the equivalant of a 5" hole.

You may need some extra length on your flue if the hole is Tooooo narrow, but hey.....this is for yourself so you can always add or replace after if it doesn't work

Terry

p.s.....It'll work!!.....once you party use DRY hardwood.....the smoke will be minimum and the heat intense.

[bigdavenorcott]

Thanks a lot Terry, that's really helpful.

I hadn't really thought about putting part bricks front and back;I'd been going to leave a half brick gap at the rear, but hadn't figured out how the dome transition would work yet. Your way is much more satisfactory!

Right, back to cleaning and cutting old bricks....

Cheers

Dave

EDIT: I didn't mean dome transition, that's the inner arch. Brain melting.