Problem: An old house that moves around like a hound on the scent. Centered in one wall is a brick fireplace and chimney. Original construction is wood lath/plaster over studs for the wall and plaster only over the masonry above the mantle, all on one plane. Needless to say, there is a crack between the wall and the chimney that, I’m sure, will just keep on coming back unless I make some modifications.
Solution: What I’m thinking of doing is to shim out the existing wall 1/2″, install a sheet of 1/2″ ply over the chimney, spanning the distance, fastening it securely to the adjacent studs and only lightly to the masonry (if only to keep it from bowing out in the future). Then drywall (or maybe blueboard and plaster) over the whole wall.
Anyone have any better ideas?
Mike Hennessy
Pittsburgh, PA
Replies
An old house that moves around like a hound on the scent.
Hi Mike. Your colorful description makes me think I'd be better off looking at foundation and structural issues prior to coming up with solutions for making cracks vanish. Even an old house, if its on a good foundation, shouldn't have much movement.
jt8
"Take your life in your own hands, and what happens? A terrible thing: no one to blame." -- Erica Mann Jong
Foundation? LOL!!! I think the inspector was on vacation when this house was built! (75+ yrs. ago. Heck, there may not have been inspectors here then.) The "footer" is about 3" of "concrete", not much wider than the block, and no rebar that I know of. (Or so it would seem from the excavating I had to do to replace the house drain & trap.) There are some cracks in the block walls, none too severe, and I have been told that they are caused by the clay the house sits on expanding and contracting due to changes in ground moisture -- "nothing to worry about structurally". (Hope they were right!) Solving the problem "correctly" would cost more than the house is worth! (New footers and foundation.)
So, I've pretty much accepted the fact that I'll live with the settling and do what I can to minimize the effects. That said, my hunch is that, although the chimney likely has a beefier foundation than the rest of the house and thus moves less, this is not a settling problem. I suspect that the real problem is diferences in seasonal movement between the wood-framed wall and the masonry chimney. Trying to span a joint between such structurally dissimilar materials with only plaster is not something I would normally try to do even with a *great* foundation! So, I'm thinkin' I need to have the span over the mantel tie firmly into the wood framing and float over the masonry to avoid the differentials in movement, with a minimum of space lost to wall redesign.
Mike HennessyPittsburgh, PA
Any chance you could use 1/2" durarock or some other fire resistant material to fasten to the chimney just in case the masonary work/mortar is not as intact as it once was. I'd hate to see any combustable material up close to the path that heated gasses and smoke travel. Just a thought.
This sounds like a problem/opportunity to maybe do a little change in the original design of the fireplace to accomodate your situation. Regardless what you do, if you tie the brick fireplace to the structure of the adjoining walls, eventually, you'll be dealing with more cracks. Have you considered doing the fireplace fascade in something different like tile or stone or even cleaning off the old brick where you have an obvious change in materials at your problem point? And glsstep makes a valid point about combustables near an old fireplace... Most of this would involve your aethetics and preference. Nonetheless, taking the problem and making it into a design change could bury the problem for good by accenting the area rather than trying to blend it into the entire wall. Just another thought to ponder...
Hmmm. For some reason, this thread vanished from my PC and I had to dig a bit to relocate it. Sorry for the delayed response. Anyhow . . .
glsstep said:
>Any chance you could use 1/2" durarock or some other fire >resistant material to fasten to the chimney just in case the >masonary work/mortar is not as intact as it once was.
Fire issues/code was and is my main concern. However, the chimney is in good shape and lined (tile), and is covered with approx, 3/4" of plaster which is an effective firestop, no? I'm not sure durarock is available in 4X8 sheets which is what I would need to span the width of the fireplace. In response to Homewright's post, tieing the masony into the adjoining structure is exactly what I have now -- the plaster is applied in a single plane over the brick and the adjoing walls. I'm trying to break that connection by floating the wall over the masonry instead of tieing it in. I am considering what you have suggested regarding facing the chimney with stone, though. That said, one of the other options I have been considering is to panel the walls of the room with wood raised panels, since it's an Arts & Crafts-style (sort of <g>) home. And, there's already a wood mantle. So, assuming the plaster is intact, and in good shape, how would spanning the overmantle with plywood over the plaster be any different than paneling, which I've seen done a lot?
Just so I'm sure y'all understand my existing conditions, here's an attempt at an ASCII illustration of the situation: Crack Crack Interior / /========== =============== ========== <--- Plaster|| || || XXXXXXXXXXXXXXX || || || <--- Stud wall========== XXX Masonry XXX ========== <--- Exterior sheathing XXXXXXXXXXXXXXX XXXXXXXXXXXXXXX Exterior
Just trying to avoid being stoopid!
Mike HennessyPittsburgh, PA
spanning the gap with furring and then sheetrocking or skimcoat paster on blueboard is the way to go. You not only have a problem with the foundation moving, but the cimney in an exterior wall also means there are thermal differnces between wood/pl;aster and masonry fighting with each other like the bobcat your hound has finally caught up with
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Thanks, Piffin. That's what I pretty much what was thinking, just that I thought I'd use 1/2" ply for the furring to save some space and span the chimney. I thought of using metal chanels as an option as well.
Mike HennessyPittsburgh, PA
reason thread "vanished"The default sttings are for the left column to display messages unread by you. once you read all that is there and come back and no new postings were made interim, htis thread will not show to you. To find it, hit the upper left drop-down menu and chooseone of the other options, like threads of high interest to me.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Yeah. I know that's the way it's SUPPOSED to work! <BG>. For some reason, it just wasn't. I couldn't even bring it up by doing a search or asking for "all to me". (The only way I knew there were new posts was the e-mail notices I got.) Anyhow, all's well now! Thanks again for the advice.
Mike HennessyPittsburgh, PA