Does anyone know if the clay tile liner is required to extend any certain amount past the cap .
Picture is from my video pole for obvious reasons.
Your PIC doesn’t show a “cap.” However the liner should extend 2" above the crown, splay or wash. Source: http://www.nachi.org/comsop.htm#17 17.8.6.4.
Thanks .
I purposely omitted that fact to see if noticed.
Had stains and readings from the attic on my meter of course.
Check out this :"Hot seat " that was next to it.
![Space heater [1024x768].jpg](https://global.discourse-cdn.com/internachi/original/2X/6/67832c759c0dc2f3181186304c5bef69b3cd081f.jpeg)
This was looking the other direction.
![creepy attic [1024x768].jpg](https://global.discourse-cdn.com/internachi/original/2X/2/24085f80fe29c58e80df674d34b43701b583c95d.jpeg)
If it is a double wythe brick chimney it is not required.
all the way to the down BOB.
A single width chimney or a gas or other inset a liner of ( galvanized or stainless ) The second choice being the best , is required and HIGHLY RECOMMEND.
The gas burns as a lower temperature and the exhaust is highly toxic and acidic and will eat through clay tera-coata liners and brick very quickly. The repair for such an event can be costly depending upon the repair needed.1.) No Concrete crown. Some call it a cap ( CROWN ).
4" wider than the brick or concrete CMU’s. Projecting over the surface of all the clay or CMU units with a curf cut or relief under the first 1" to act as a rain stop .
2.) No rain cap.
A cap is for rain or a spark arrestor.
Looks short BOB.
The liner should be a minimum of 2" in your INACHI EXAMPLE .
I have seen specifications for the liner to be higher. 4" being a standard requirement.
I always installed the liners a minimum of 6" inches. It prevents back drafting in windy conditions.
Will look for some Canadian codes and recommendations for your cold northern, locked in ice and snow INCHI BROTHERS.
CROWN must be 4 inches high and 4 inches wider than the chimney body ( on all sides ) of the structure.
The bottom or lowest side of a chimney CROWN.
A concentric cut 1’ from the farthest point, A cut in the concrete of 3/8 wide and 1/2 deep and within the first 1" inch of the total parameter of CROWN.
This acts as a kick-out and stops the advancement of water to the brick.
The last course of brick on a chimney can be affected great by moisture.
The most critical part of the chimney to inspect in my opinion, the CROWN. Look for cracks.
Then were the CROWN sits.
Look at the 4 courses under the **CROWN **for cracked masonry bedding and head or butt joint bedding and also for spalled brick.
Hypotheses only.
When wind ( atmospheric pressures ) come into contact with the chimney structure the forces go in all directs.
The uplift forces come in contact with the underside or over hang of the CROWNS 4" over hang.
The intersection of the 2 planes is a right angle. 90 degrees
It start a turbine affect when the winds or uplift atmospheric pressure come into contact with the planes 4" exposed right angle.
The stronger the winds the greater impact.
It creates a tornado on its axises or side.
It is carried over the CROWN.
Several conditions may occur.
All can affect the ability for the chimney draft positively or negatively.
The height of the liner will stop the atmospheric turbulence from running down the chimney CROWN opening causing any instability.
A positive pressure or Back drafting can be created without a properly installed liner to act as a shield or break.
The liners height is important along with the CROWNS, WIDTH, HEIGHT AND CIRCUMFERENCE.
With improper building conditions" and or " improper maintenance are carried out the ***CROWN **and **liner, it *can play a pivotal roll in deficiencies and degrading material and system.
I am being rough in my description.
I will look to polish it up and prove my hypotheses.
Looks like an unlined chimney to me.
The liner is missing or never installed.
It was a flaunched cap on the stepped brick.
The stepped brick where to give the illusion of a crown.
The CROWN must extend the chimney in all directions by 4 inches.
To protect the last several courses from Moisture.
If I rebuild a crown this year I will save it on video.
SUSPECT: It is a single width chimney with no liners.
Now you have to look down the chimney to see if a liner was extracted and to look for deficiencies when inspecting. If you can.
Terracotta liners come in 2" foot sections.
Sometimes removed because it was deficient. Cracked.
No one replaced that top section? That is the hypotheses right now.
Easy to do the math to see how wide the interior is.
Measure the exterior subtract the 3.3/4 or 3 7/8 or what ever the brick width is.
Will a liner go in the void?
The smallest terracotta liner is 7/7". It is 1/2’ inch smaller in diameter. 6.5 inches
Or metal liners go down to 4". I have not heard or seen smaller.
The metal liners protrude out of the top by 4 to 6 inches and can be pulled lightly to get more room to fit your CAP.
Now calculate: inside the chimney is rough. Masonry squeeze or unfinished jointing. No tuck.
When a chimney is REPAIRED OR BUILT.
AT TIMES, You will leave a 2" minimum void all around to allow the liners to stack as you build your chimney minamum15’ feet.
The liners are held in place as you continue building up.
First the build the brick walls then insert the liners at a certain point depending on many factors…
You plumb the liners buy using masonry and broken brick I am free hand guy and use brick for wedging.
You try to leave airspace to allow for RH to escape.
You are allowed 1/16 in offset plumb. Multiply that by 60 courses and you understand the 2" gap. To allow for play.
More to it than that.
I will try to develop a inspection routine for chimney inspections for INACHI INSPECTORS.
Give me time.
That’s how it appears from my vantage point…
Thanks guys.
That was close as I could get and actually had to climb my ladder to get that high.
No actual cap and there is a clay tile liner that shows better on my video since I simply took a still off it for you guys.
I knew not having it extend was wrong as well as not having a cap if I read you right.
That is what I put in the report .I posted late because I had to do the report after my NACHI Chicago meeting.
p.s …surprised nobody mentioned the Chicago style base flashing.
I see that here also Bob.:roll:
That’s what I was thinking.
Bill I already said it is clay tile but it apparently stopped to short and the clay tile liner can be seen if you have a bigger screen perhaps.
Mid efficiency furnace and Hot water heater.(B vents) though as you can see there is a space heater in the attic which ties in also.
I have flashed like that for over 15 years or more BOB.
It outward bend int the chimney’s counter flashing is called a GUM EDGE.
It accepts a larger amount of caulk.
What is that HOT SEAT BOB. I have never seen one.:roll:
Electric or is the chimney attached to it?
Ha ha ,that is the space heater Robert.
It is funny when you look at it as a photo BOB.
I thought it was a space heater but have seen gas reflective heaters in 3 season country homes that have ducting that look similar.
Forgot to give you a link yesterday.
Cover some good fireplace subject matter.
Have a geat day.
http://www.superiorclay.com/pdf/catalog.pdf
No fireplace here Robert.