Thread: Residential Chimney Question

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

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Dave, we would love to see a pic

thanks in advance

Originally Posted by Stephen G

Dave, we would love to see a pic

thanks in advance

Well, there is not much to take pictures of, aside from a new chimney.

Just wondering if

a) I was taken for a (expensive) ride

b) if the new chimney was constructed correctly


The old one was not attached to the house above the rake, except by the flashing, which had clearly been patched (poorly) a number of times.

The old siding was behind the old chimney with about a 1/2 air gap. That space had been caulked along the seam between the chimney and the house, but it was damp, and in fact had some vines growing on the siding.

The contractor removed the siding behind the chimney, beefed up the existing T&G sheathing with 5/8 ply, added ice and water dam, and tied the chimney into the sheathing every 4 courses with brick ties.

-dave

Attached is what NC says about chimneys...

David, If you want it from an authoritative source then contact CSIA.org.
These guys will knock your socks off with excellent info.

You'll also find very good info at gobrick.com. Click on Technical Notes and find the appropriate PDF.