Chimney/Fireplace Footing Size (and a few other questions)

Old 09-20-12, 07:41 AM
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Chimney/Fireplace Footing Size (and a few other questions)

Greetings to everyone who reads this post and thanks to all who reply.
So I am building a house and doing a lot of the work myself while also hiring some local people who have some experience. I am ready to pour the footing and the foundation plan includes a footing bump out for a chimney. I would like to connect a fireplace to this chimney on the first floor. The foundation type is basement with 10" block. I would like a clean-out in the basement but I am not sure if that is a good idea. Should the clean-out instead be above grade on the exterior? I would also like to include a second flue that goes down to the basement level in case I ever want to add a wood stove or fireplace down there.
So what I am looking to do is build the chimney from the footing up so that I can accommodate a fireplace on the first floor and possibly a fireplace in the basement too, or a wood/coal stove. My furnace will be power vented so I don't need a chimney for that but maybe I should have an additional flue in order to accommodate future possibilities?
Essentially my initial question is should I expand the size of the Chimney footer beyond the plan dimensions of 5' X 2'? Is it OK to have the chimney footer as an extension of the foundation wall footing? I read that the load is different on the chimney versus the building wall and that the two are sometimes separate.
I have been doing some research and it seems that it is required that I have a vertical rebar in each corner of the chimney that is anchored in the footing. The chimney walls then get tied to that. Is that all I should do in terms of below grade reinforcement (the footer will have horizontal rebar)? I also need some advice on the construction of the flue(s) that will extend down into the basement level. I was thinking that I would use concrete block to outline the chimney below grade and just work my way up until I get above grade and then stop until I find someone to build the fireplace. So if I do it that way I need to get the lower part of any flue correct so that the mason can take over without any excavation (or demolition). So I was thinking that any flue I put in for the basement level would be off to one side and so I would extend the width of the footing on that side. When building the section of the chimney that is below grade I was thinking that I would use regular 8" block all around and then use chimney block with the clay liner for the flue(s) that extend to the basement. So one question I have about that is; is it OK to use a narrower block on the side with the flue and then put the chimney block within the outer blocks or should the chimney block be the outside block as well? By chimney block I mean those blocks with the square center that accommodate the liner. If I wanted two flues going down to the basement (one for a wood/coal stove and the other for a furnace burning a different fuel in addition to my fireplace what size footing should I pour? What size should my flues in the basement be? If the clean-out is in the basement can the ash just fall down into the open area between the blocks that make up the outline of the chimney? One final comment is that I am looking for a mason to guide me on this but I thought that is is possible that someone here could give me enough guidance so that I can just do the lower part of the chimney with the crew that I have helping me do the block walls. I have already realized that none of them have the right experience in chimneys. I need to pour the footing next week and get the block walls up and the floor deck on and insulated before the ground freezes. Thanks!
Old 09-20-12, 05:50 PM
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I've seen interior & exterior cleanouts. Of course, I would go with exterior. May I ask who drew the plans for the house & why wasn't all that included? Am I correct to assume that there is no building inspection involved?
Old 10-01-12, 12:29 PM
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Chimney and foundation considerations

I recently built a large addition (1200sf) and one lack of foresight was in the foundation area. I did not pour the footer for the basement steps going outside. I bring this up as it is important to have adequate drainage around the fondation, drain tile and stone and you want it the drain tile to go around your chimney foundation, have connections to any window wells and below grade drains such as steps going out. how the drains and drain tile is kept clear of debris during the foundation pour is important also.

I would put the cleanout outside, having it inside is an asthma and health risk IMO.

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