Thread: Masonry chimney wrap

Interesting find yesterday - masonry/brick chimney base, wrapped(?) with wood siding. I'm puzzled by method of attachment they may have used for this project, and whether this .

The house was remodeled ~15 years ago - wood siding installed to cover older existing siding, including wrapping the chimney too. Brick chimney base could be seen at the bottom 2 feet, and wood siding for 2 storys, including wood siding at roof for a chimney chase. Unable to see any of the chimney structure other than the bottom 2 feet.
Attachment method to hold up the full height of the chase is unknown. I've disclaimed this in the report. Dont know what to tell them other than a masonry chimney is required to have clearances and not designed to support a load.
Wrapping it? Could wrapping it cause other concerns such as trapped heat when in use?

Looks like they did a nice job - they might have even done it right by using a steel lining for the chimney as well - I think you were smart to disclaim it and I think we shall see many more of these showing up with direct venting for heating systems and Hot water heaters (I am suspect that is the case here and the flue is for a fireplace or wood stove ? -

The real question is what is the purpose of the chimney now - to hold the lining ? support the siding ?

I suspect that it is simply a frame chimney chase with metal chimney sections installed within the frame chase.

It's a standard masonry/brick fireplace inside, and I could see 1 or 2 tile flue liners up inside - but very limited view up the flue.
The house is originally 1955 with a newer remodel - which, I suspect is when the wrap occured, but because of the age, likely was an all brick chimney structure.
The metal termination cap had rusted screws so I didn't remove to look down the flue.

Two intersecting roofs behind chimney, looks like there is no slope. Where is the water to go? I would be concerned about water entry behind wood which is in contact with shingles. Where is the flashing.

Good catch Raymond, but actually its ok. Just that it's hard to see there is a down slope about a foot behind the chimney where the valley ends - not a cricket, but a continuation of the slope from the left. Note how the siding at the base of the chimney chase is sloped to mirror the angle.

The real issue is - was the chimney given a steel liner (not as original but more recent) or is it clay tile on the inside - I think it is important for the future home owner to know this. Strapping that is used to hold the siding is attached to the mortar somehow and if there is no liner then there could be leaks (fire hazard , co hazard). You really need to be able to look at this stuff and also to see what kind of condition is the brick itself - for all we know the siding is covering up a crumbling chimney

Another comment was made about flashing - I thought about that now after writing - I see this as a potential problem as well maybe even draining into section between the chimney and the nice looking siding.

Again , I think you were smart to disclaim it - this warrants much more investigation and code checking as well.

So what about the heating system and Hot water heater - where do they vent to ?
(from the picture it looks like it had 2 flues )

Possible second story addition? I've seen them extended like that. In fact, I have an extension like that on my house, although we didn't bother wrapping it. We capped the clay flue with a metal flue and extended it up another 10 feet or so.

Wrapping the chimney with combustibles brings it into the house and must be treated as an interior chimney requiring a ventilated 2" clearance to combustibles, which I seriously doubt you have. The pipe is not a liner but a factory built listed chimney. It must be sized to 1/10th the opening size of the fireplace. Figuring a nominal 30"x30" fireplace opening, you're looking at a min. 11" chimney, which I seriously doubt that is. Looks more like 8" rd. Several mfrs. of listed chimney make a listed masonry transition but not all. You cannot downsize, which is a problem with rectilinear tiles. The hearth extension is too short and needs to be assessed for proper support without combustibles under it. The chase would have to comply with the building code. It would need to be balloon framed for inherent strength, which is hard to do when extending a masonry chimney. Depending upon where the transition is made, you'd need a listed firestop with approved fireblocking at each floor/ ceiling or every 10ft.

Recommend a Level 3 internal inspection, which includes a level 2 with a video camera internal inspection by a qualified pro.

Dwight - yeah, i think this siding wrap is concealing too much information for my comfort. There is a big question mark about this that I can't answer - so off it goes to the next level of inspection.
About the flues for water heater and FAU - these are separately located and not part of this chimney.

Jim - yeah, I wondered about that too - if it's a 2nd story addition. I don't know, but there is evidence of additions, and I'll be recommending a permit search.

Bob H - that's what I was looking for. BAM! Thanks for the info. I'm going to use some of that for the report (if that's ok). Great information.

"Wrapping the chimney with combustibles brings it into the house and must be treated as an interior chimney requiring a ventilated 2" clearance to combustibles" Did not catch that one. Whew, glad you logged on - thanks again. When I looked underneath the base of the wrapped siding (hoping to see up inside), there was no clearance or cavity to see - just wood framing against the bricks - a relatively tight fit.

The hearth extension was 16" but still had wood forms underneath - as do most of the hearth extensions I see. "Its just too much trouble to go back under there after the mud dries."

Thanks again for all the info