Ridge beam at chimney

Started by Tome, September 15, 2012, 06:23:30 AM

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Tome

I am new to this forum and not a builder by trade so please excuse me if my wording is not correct.

I need help with supporting an exposed  ridge beam conflicting with a chimney. I do not want to oversize the masonry (if even allowed). I am sure this has been discussed and resolved before. Pictures would be great.

Oh yea, I am building a small cabin from sawn lumber here on my farm in eastern N.C.

Redoverfarm

Right , wrong or indifferent I pockected by ridge into my fireplace flue.  The biggest concern that I can see is ample support for the weight load of the roof, clearence from the fire path and then there may be settling.  Mine was centered in the flue. Not sure where yours will hit.  Generally the flue should be seperate and flashed to make that connection between the roof, chimney and the framed structure.  But in my case I was unable to head off that intersecting wall connection to adjoining verticle beams because the area adjacent to the flue was open on all 4 sides.  You might be restricted by local codes so I would look at that aspect as well.  I tried to find some information and was able to locate some information in the following website.

http://forums.finehomebuilding.com/breaktime/construction-techniques/support-ridge-beam-chimney

A masonry stack is best not used structurally in several instances. For one, framing should not be in direct contact with a chimney because of code concerns for fire. Various codes require one or two inches of separation. The latest makes allowance when a full 12" of masonry separates between the wood framing and the fire path in the chimney.


Another concern is for the connection between the two elements. Gravity alone has been used in places for hundreds of years but in seismic zones, you really don't want the beam sliding out of that pocket. Another concern is for type of mortar. Let's say you are trying to suppport a load on round river rock veneer stone face with poor lime based mortar. I wouldn't necessaryily expect it to handle the thousands of pounds you might be putting on it. Having an engineer design a pocket flange for the amt of weight it will bear with tie that beam to the chimney right.


But the first thing that went through my mind on this question is that since you have a gluelam supporting as a structural ridge, the placement of the chimney will affect that sizing, making it smaller if the chimney penetrates the ridge, and possible saving some bucks, but it might complicate things from the design, engineering, and labor viewpoint.


Tome

Thanks for the reply.

It sounds like between code issues and bearing issues I need to just offset the fireplace. It just looks better to me centered.

I have accumulated a lot more questions I will send under separate cover.

Thanks again,
Tom

Redoverfarm

Quote from: Tome on September 15, 2012, 09:12:54 AM
Thanks for the reply.

It sounds like between code issues and bearing issues I need to just offset the fireplace. It just looks better to me centered.

I have accumulated a lot more questions I will send under separate cover.

Thanks again,
Tom

Tom if that is what you want I would try to do more research and see if it is possible.  Maybe someone on here can shed some more insight.  The worse case scenaro is that you may have to offset it. 

G/L  John

PEG688

Could you post to bearing on either side , or is that the side / sides the fire box has to be on?

If you could post up and box out the fire place could go out the center, flashing it will be more complicated going thru thru ridge.
When in doubt , build it stout with something you know about .


JRR

One might plan on laying in some black pipe "spools" in the chimney masonry.  The spools should lay all the way though the chimney section, avoiding direct contact with the flues.  The black pipe spools allow one to pass some all-thread rods (Make 'em large... 3/4" or larger) thru the chimney to attach to angle iron brackets, or whatever, to attach to the wood beams.  It would be easy to stand-off the beams using washers, or large pipe, .... or letting the spools extend beyond the chimney masonry. 

Food for thought!

Redoverfarm

Quote from: JRR on September 15, 2012, 03:16:40 PM
One might plan on laying in some black pipe "spools" in the chimney masonry.  The spools should lay all the way though the chimney section, avoiding direct contact with the flues.  The black pipe spools allow one to pass some all-thread rods (Make 'em large... 3/4" or larger) thru the chimney to attach to angle iron brackets, or whatever, to attach to the wood beams.  It would be easy to stand-off the beams using washers, or large pipe, .... or letting the spools extend beyond the chimney masonry. 

Food for thought!

Would that not make them attached solidly to the chimney rather than the chimney be free standing by itself.   ???  If it is permissable then a pocket would essentially work.  The area where the flue is present would have to be headed off (similar to skylight) for the rafters that were replaced by the flue.  Brackets could be fabricated to attach the rafters running adjacent to the flue.  But is this sufficent to pass any codes if applicable.  I am not sure.

Redoverfarm


Tome