David Dolch
01-16-2012, 07:01 AM
I have read the various threads on chimney design and am still confused.
I had an inspection done on the home we recently purchased and the inspector specificaly omitted certain parts of the roof because of snow cover. Well, the snow has since melted.
I had the fireplace chimney (on the exterior of the gable end of the house) cleaned and the sweep mentioned problems with the flashing. I went up and looked and the flashing was clearly patched, and the patch was also cracking. There was efflorescence in the firebox (which the inspector mentioned) and the though was this is where water was penetrating. The cap of the chimney was also cracked and needed some patching.
The sweep came back to do the repairs and removed the old flashing. That is when we noticed that the chimeny was not attached to the house - no brick ties. When the flashing was cut, you could push on the top of the chimney and move it 4-5 inches. In addition the chimney was built around the protruding fascia. In other words the bricks were stepped back to clear the 4" or so fascia, as opposed to the fascia being removed and the bricks laid up plumb.
There is no evidence of settling of the chimney foundation. The fireplace and chimeny were most likely built after the house was built (+/- 1974). There existing cement siding is behind the chimeny and as I said, the fascia was also continous.
So - what is the proper way to build a chimney? Should there be brick ties every 4 courses as you would build a wall? If it is supposed to be two inches away from the siding (or sheathing) then what fills that gap - backer rod and caulk? No brick ties make sense on one hand - interior chimneys dont have them, and they are 2" away from all framing with firestopping, but then brick sheathing has them, and they dont have quite the same wind loading as a chimeny.
I can't seem to find a consistent, authoritive answer. The chimeny guy tells me one thing, internet sources another, looking at other chimenys around the area (Northeast NJ) shows a variety of ways they are constructed.
Thanks
Dave
I had an inspection done on the home we recently purchased and the inspector specificaly omitted certain parts of the roof because of snow cover. Well, the snow has since melted.
I had the fireplace chimney (on the exterior of the gable end of the house) cleaned and the sweep mentioned problems with the flashing. I went up and looked and the flashing was clearly patched, and the patch was also cracking. There was efflorescence in the firebox (which the inspector mentioned) and the though was this is where water was penetrating. The cap of the chimney was also cracked and needed some patching.
The sweep came back to do the repairs and removed the old flashing. That is when we noticed that the chimeny was not attached to the house - no brick ties. When the flashing was cut, you could push on the top of the chimney and move it 4-5 inches. In addition the chimney was built around the protruding fascia. In other words the bricks were stepped back to clear the 4" or so fascia, as opposed to the fascia being removed and the bricks laid up plumb.
There is no evidence of settling of the chimney foundation. The fireplace and chimeny were most likely built after the house was built (+/- 1974). There existing cement siding is behind the chimeny and as I said, the fascia was also continous.
So - what is the proper way to build a chimney? Should there be brick ties every 4 courses as you would build a wall? If it is supposed to be two inches away from the siding (or sheathing) then what fills that gap - backer rod and caulk? No brick ties make sense on one hand - interior chimneys dont have them, and they are 2" away from all framing with firestopping, but then brick sheathing has them, and they dont have quite the same wind loading as a chimeny.
I can't seem to find a consistent, authoritive answer. The chimeny guy tells me one thing, internet sources another, looking at other chimenys around the area (Northeast NJ) shows a variety of ways they are constructed.
Thanks
Dave