Framing Rafters to Meet Clearances

[dpgoalie]

Hello,

I have searched the threads for a solution to what I think is a common problem, but I have come up empty handed. If a thread exists, please point me to it.

I am doing a chimney install in a shed/barn type of building. The roof peak is about 11 feet tall. I want to run my cinder block chimney up through the rafters, then brick my way out of the roof so that it looks nice. I will brick the cinder block in later and insert a stainless liner into it. However, my rafters are all spaced differently and the two I want to go through are spaced 18 inches apart. This is the width of the chimney block. So I need to move a rafter.

My question is, should I move a rafter or cut one and do some sort of box framing? I do much better with pictures and diagrams. If you know where there is a picture of this type of box framing, please provide it.

Thank you!

 

[ironpony]

you can cut it and add double headers on each side and attach the rafter to that. use hangars on all the attaching points.

 

[ironpony]

like this, you will cut only one rafter

 

[bholler]

You also either need to confirm that the existing rafters can take the extra load or double up those rafters as well. But if you have 18" between them and install an insulated liner there is no need to move them at all

 

[dpgoalie]

You also either need to confirm that the existing rafters can take the extra load or double up those rafters as well. But if you have 18" between them and install an insulated liner there is no need to move them at all

The existing ones can handle a load, but the actual space between them is 16". Not wide enough for chimney block.

I do plan on dropping an insulated stainless flex liner.

 

[dpgoalie]

View attachment 160100 like this, you will cut only one rafter

This is simple. I wish I didn't have to cut a rafter, but I can do it.

Thanks for the diagram.

 

[bholler]

The existing ones can handle a load, but the actual space between them is 16". Not wide enough for chimney block.

Ok you original post said 18". If it is 16 you will need to re frame. I know your current set up handle the load but what i was referring to was if you cut out one and transfer its load to the adjacent ones you need to be sure those can handle the increased load.

 

[xman23]

Wonder why your going through all the work of a masonry chimney, and not double wall class A, SS. I know you said you liked the look of brick. If it's a stove your doing, a straight drop to the stove, makes cleaning easier. Draft will be better. And that chase through the rafters is 12" x12". So you only need to cut out one one rafter.

 

[dpgoalie]

Wonder why your going through all the work of a masonry chimney, and not double wall class A, SS. I know you said you liked the look of brick. If it's a stove your doing, a straight drop to the stove, makes cleaning easier. Draft will be better. And that chase through the rafters is 12" x12". So you only need to cut out one one rafter.

I think I still only need to cut out one rafter.

I also feel as though stainless will look out of place on a 100+ year old barn. Just not my style for this particular application.

 

[Jo191145]

The default position is you always double the rafters on both sides.

Is there a reason you want to use block construction wrapped with bricks at a later date? Wouldn't it be easier and cheaper to just use bricks now and not need the blocks?

 

[dpgoalie]

The default position is you always double the rafters on both sides.

Is there a reason you want to use block construction wrapped with bricks at a later date? Wouldn't it be easier and cheaper to just use bricks now and not need the blocks?

I can double up on both sides.

I have never built a chimney before and I am under a time crunch as I am in the middle of putting an addition on the barn and an entire new roof. My thought was as a first time chimney builder, it would be quicker to go from the foundation to the roof with chimney block, then I can face the block in brick at some point next year. I also thought since I have to work as fast as possible, it would be easier to keep the block level as opposed to all of the brick.

It certainly makes sense to build the whole thing in brick. Can I drop an insulated, stainless steel flex liner into a brick only chimney?

My buddy who is a mason was supposed to come and "throw up" my chimney was supposed to do this for me, but he is about as reliable as freshly cut White Oak in the month of January.

 

[ironpony]

hey just thinking out loud,......now realizing what you are trying to do. Build a frame chimney chase and wrap it with veneer/face brick if it is up that high no one will know. save a lot of masonry/cost too.
cosmetically look good and be cost effective.

 

[bholler]

hey just thinking out loud,......now realizing what you are trying to do. Build a frame chimney chase and wrap it with veneer/face brick if it is up that high no one will know. save a lot of masonry/cost too.
cosmetically look good and be cost effective.

A ss lined masonry chimney will be cheaper that a veneered chase and class a

 

[kennyp2339]

A ss lined masonry chimney will be cheaper that a veneered chase and class a

Plus, with a masonry chimney you need to factor a good size footing to hold the weight of the masonry.

 

[dpgoalie]

Plus, with a masonry chimney you need to factor a good size footing to hold the weight of the masonry.

It's an 8" concrete slab.

 

[dpgoalie]

A ss lined masonry chimney will be cheaper that a veneered chase and class a

I just priced it out and my original plan is the cheapest. Masonry block to the rafters, brick the rest of the way, drop a flex liner in.

I'll think about bricking the whole thin when I get into it. I'll go that route if I feel I can do it quickly.

 

[bholler]

I just priced it out and my original plan is the cheapest. Masonry block to the rafters, brick the rest of the way, drop a flex liner in.
I'll think about bricking the whole thin when I get into it. I'll go that route if I feel I can do it quickly.

Yes if you are doing the labor lined masonry will absolutly be cheaper. And if you have never done masonry before block is a good choice. Laying up a brick chimney is not the easiest thing to do.

 

[dpgoalie]

Yes if you are doing the labor lined masonry will absolutly be cheaper. And if you have never done masonry before block is a good choice. Laying up a brick chimney is not the easiest thing to do.

I'm pretty meticulous in all that I do. But I guessed that block would be easy.

Thanks for the help.