Rungs on chimney (but not for Santa)
During construction I would like to put some type of rungs on the part of my fired clay brick chimney above roof level to make inspection/ maintenance easy and safe (for me). (Woodburning fireplace, st. steel chimney liner.) I would put them on the proximal (side farthest from view) side of the chimney. I’m thinking of using #4 rebar about 28″ or so long bent in a “U” shape with the two ends entering the mortar the 3-1/2 ” brick width and protruding about 4″ out from the brick. Other than the “problem” of occasional maintenance of touch-up painting to prevent rust stains running down the side of the chimney, does anyone have any disadvantages, suggestions, improvements, simpler ways, comments or experiences with such a scheme? Southern Ontario climate.
Thankyou – Brian.
Replies
I would think that if you just stobbed the rung into the mortar joint between bricks you would likely pry the joint apart. Mortar joints don't have much tensile strength.
The ladders I have seen mounted onto brick walls were units that combined rungs and were hung from the wall face by way of anchors drilled into the brick faces. This puts the anchors in shear with only a little withdrawal force, the anchors strong points, and kept the forces on the bricks primarily in compression. The bricks strong suit.
To do this you might use an upright with the rungs welded on perpendicularly. The uprights would also have tabs, predrilled for anchors, welded so they fit flat against the bricks face and spaced to hit the middle of the bricks faces not the mortar joint.
You might want to add reinforcement to the brick courses involved. Check with an experienced mason about the reinforcement. Any good metal fabrication shop should be able to put he ladder together for you. I'm just an electrician and I'm guessing based on what little I know about the strength of materials and design so maybe a more experienced contractor or design person will correct or improve on my ideas.
I can't say I have ever mounted any ladders to bricks but I have mounted a few transformer platforms and some conduits to brick walls. As far as I know none have fallen down or damaged the wall beyond what was necessary to do the installation.
Thanks 4LORN1 - I will consider a single ladder unit.
However, with the single-rung scenario I was thinking that I might minimize the pry-apart forces by having the rungs take a bend in the downward direction after they extend outside the brick surface. Technically, it will reduce the rotational moment of the part of the rung that is embedded in the wall, and more force will be directed downward (compression) at the front surface of the brick, and less upward (tension) at the back interior surface of the brick. I guess the pry-apart forces would also be reduced depending on how many bricks were above the rung joint, as their weight would contribute to holding the joint together. (To help me visualize this I'm considering here what the hypothetical situation would be like with the rungs stuck in a stack of bricks without any mortar at all.)
I will take your advice and check with the mason before I do anything.
Best regards - Brian
Think Stainless steel
If you just bend them that won't realy have any affect. If cut take a cross section of the rod where it goes into the brick it will still have exactly the same forces on it.
What you can do it to add another piece to it so that it has a "back" that reset against the brick. That is basically make a single step version of the multiple step ladder that he mentioned earlier.
I think you're right Bill - The sloppy vector diagram I drew in my head last night was errant. It's just the distance out from the wall that the rung extends that really has an effect on multiplying the splitting forces between the bricks.
Unfortunately stainless isn't within my budget, and even an old pool ladder wouldn't make it past my wife's watchful eyes. ; )
Thanks guys - I'll see what my mason can come up with.
Rgds - Brian.