Chimney fell off the building

[geotek]

I got a startling call the other night, apparently the chimney fell off of the back of my mothers garage. Its was a CMU chimney that (apparently) was never secured to the garage. So over time it began pulling away and then finally fell away from the building.

My question is this: I don't want to spend $$$ for a new CMU chimney and would like to put up just a generic single walled "metal" pipe up the back of the (CMU) building. Nothing fancy, since no one will see it except me and the trees. Any suggestions or recomendaitons on products or advice on installation?

I'll post pictures next week after I inspect the damage this wekend.

 

[Charles (in GA)]

OK, After Googling CMU chimney (never heard of that term before) I find that it refers to chimneys made with concrete blocks and having a premade interior flue liner put into it. Thats probably what is on my house (don't use it, never have, never will) and what I watched my former land lord down the road build on his house several years ago (he is pretty crafty and good at doing this kind of stuff).

You need to replace it with a double wall. You need the insulation for protection of adjoining structure and surfaces from heat, but just as important, you need the heat retained in the chimney to create a draft. With single wall, you could end up with no draft or actually have a downdraft and lots of problems.

Metal double wall insulated will be expensive, but nothing like the old masonry unit. Those masonry type chimneys require a good solid foundation. They don't need to be "secured to the house" they just need to stay upright. I have two neighbors who have had to their chimneys braced, excavated underneath, jacked up level and tons of concrete poured into the hole around the jack to make a solid foundation. Once that was done, they never again tried to pull away from the house.

Charles

 

[phbsales]

If you are rebuilding the chimney with metal, you will save yourself a lot of future repair issues by using double-walled pipe, stainless steel construction.

At the bare minimum, it should be at least galvanized steel, since stainless is extremely expensive, but stainless won't rust.

 

[lametec]

When I redid my roof a couple years ago, I noticed that my chimney was about to fall down as well.

I solved it by knocking it down and replacing my old furnace with a side-vented hi-eff unit.

 

[Highbeam]

You will find that building codes do indeed require the masonry chimney be attached to the structure. There are very specific requirements about this.

I wouldn't rebuild it as a masonry chimney either but no chimney is cheap. You will spend lots of money to buy the proper class A chimney pipe. The pipe can be black single wall connector pipe within the stove room but as soon as it goes into the thimble it needs to be class A from then on.

I have actually seen people salvage the bottom of a masonry chimney and then extend it to proper height with class A.

 

[larry_g]

I would suggest that you at least get a bid to replace the CMU chimney. I replaced one a few years back and it was not expensive as I remember.

lg
no neat sig line

 

[PCO6]

When I redid my roof a couple years ago, I noticed that my chimney was about to fall down as well.

I solved it by knocking it down and replacing my old furnace with a side-vented hi-eff unit.

That's similar to us. We had our furnace and water heater replaced a few years ago with high efficiency units that vent out of the wall. We are about to have our roof redone. The cost estimate for repairing the chimney was $2,500 vs. removing it for $500. The next step will be to install a gas fireplace insert ... and make sure NO ONE starts a fire in the meantime!

 

[geotek]

Thank you all.
Sadly there is nothing left of the chimney to salvage, it went over like a Jenga set according to my brother.

It looks like it'll be a pricy fix based on phone estimates from the local mechnical contractor. I'm thinking the garage is going to be very cold this winter.

As for the venting out of the wall. The furnace is an old waste oil heater. It does have a clay pipe through the wall, but I'm guessing that since it's not a high-efficiency unit, it'll still have to be vented to roof level.