Chimney flashing


#1

can someone tell me the correct way the flashing should be dealt with around the chimney.

this is on a re-roof that i’m having problems with…leak around chimney and contractor has been back twice already.

i would like to know the correct way this is done before meeting with him tommorrow.

                       thanks

#2

With counter flashing cut around the chimney.


#3

Hi,

If the contractor was back twice already. My bet is there is nothing wrong with the flashing.

Chimney probably is taking in water. Might need a chimney cap or/and waterproofing.

If you post a picture, I can help you out.

Most roofers/customers will never consider the actual chimney as taking in the water.


#4

Chimney can leak. that is why pan “thru wall” flashing with weep holes are used in many coastal areas. Also they sometimes specify Waterstruck brick because it is not as porus. But mant times I find a hack job on the flashing work, in particular the way the corners are done. In Massachusetts you have to have a cricket for any chiminy 30" and over.


#5

This is just one way to flash a chimney. This is just a basic job, nothing fancy, but will last as long as or longer than the shingles.

roofingcontractorreview.com/Basi … shing.html

But sometimes, as mentioned, it’s not the flashing. It may be the mortar or the wash(top) of the chimney.


#6

I always end up doing two layers of flashing around chimneys.

The first lower layer, I grind out the necessary mortar and run metal about 3/4" into the brickwork. Naturally, I stagger pieces with roof slope vs. mortar line situation. The flashing is nailed to the WOOD of the roof. I force mortar into the gap and smear on tar over the metal/brick joint. If this first layer is already there, LEAVE IT ALONE when you do the tear off. This layer allows expansion/contraction of the chimney while maintaining a near air-tight connection to the roof.

Second Layer is the I&W over the flashing and wood completely around the chimney. Same thing - top overlaps bottom.

Third layer is what Dennis showed in his link.

Chimney flashing is the most time consuming part of the job. Figure 1 day to tear off, 3 days for surface prep, and 1 day to put the shingles down.

Other items in surface prep are deck repairs, edge flashing, valley flashing, I&W, and felt. Surface Prep is HARD WORK. Unfortunately, it’s the easiest to hide when it’s not done.

After the shingles are on, is the WRONG time to fix a chimney leak. All I can do is offer condolences, knowing this is may be the first of many leaks you will probably have.

Get a reputable roofer up there to see what else is wrong. You might be looking at a complete tear off.


#7

“The first lower layer, I grind out the necessary mortar and run metal about 3/4” into the brickwork. Naturally, I stagger pieces with roof slope vs. mortar line situation. The flashing is nailed to the WOOD of the roof. I force mortar into the gap and smear on tar over the metal/brick joint. If this first layer is already there, LEAVE IT ALONE when you do the tear off. This layer allows expansion/contraction of the chimney while maintaining a near air-tight connection to the roof."

Five full days to do a standard brick chimney flashing? Not to be mean but are you a roofer? Never heard of a chimney done in this fashion or taking this long. Also if you are inserting your same piece of metal into the raglet and then running onto and securing it to the decking you’re wrong. The whole reason behind a standard 2 piece chimney flashing system is because due to the weight of the chimney it will settle at a different rate than the house. The 2 piece step/counter flashing system is designed to “float”. Otherwise you have the weight of the chimney eventually ripping the flashing off the roof deck. No reason to ever use tar on a new flashing either. Gross. Also last I checked bricks don’t expand and contract…

To the OP… Lefty may very well be right and your chimney/crown is taking on water. If your chimney is small enough wrap the masonry parts of it in a garbage bag or other plastic and duct tape. Make sure you make an opening for the flue! If it doesn’t leak then it’s probably the masonry. The illustration Dennis posted is what your flashing should look like.


#8

Tar, where do you see “five days”? I may have to go & re-read the post.

Also, not every chimney is brick. We get about 80% or more Hardie siding here in Central Texas & on my house, it’s Masonite (I’m changing over to Hardie).


#9

man poor roofers who cant do metal work. Makes me sad.


#10

Oh come on the bucket of tar works great.


#11

Never heard of the whole 3-layer, tar on the brick, flashing thing, sounds nasty. The main thing that I think is important is to solder all the seams on the pans and lap joints of the counterflashing. You would be suprised at all of the “so-called” roofers who do not know how to properly solder (sweat and lace) metal seams. Either because they never learn, don’t want to learn, or don’t care to learn how to solder. I would do a controlled water test, running a hose higher up the roof in front of the chimney to see if it is the flashing and then only on the counterflashing and see if there is moisture around the inside, then you may be able to determine if it is the flashing or the mortar.


#12

‘Another’ is right about the garden hose trick.

I can solder surface mount parts onto a PC board under a microscope, but I never solder flashing. Solder has no give. no flexibility. You’re right about bricks, but the house expands/contracts around the bricks. The lower flashing is a barrier to separate the house air from the chimney. I don’t like condensing water getting in there to screw up the upper flashing when it freezes.

I only do a couple roof jobs a year, I’m usually a high tech handyman. Most of my frustration is shortcuts by low bidders. I find myself fixing areas I never imagined getting into.

I’m amazed we have nail guns for roofing when it’s the easiest part of the job. I never use one.

Any good roofer will tell you that Surface Prep is the most critical part of the job. With good surface prep, 20 year shingles will last 40 years. Bad surface prep, and 30 year shingles will last 5.

If a roofing job takes 5 days, 1 day for tear-off, 3 for prep, and 1 for shingling. That’s how I explain it. The 3 days also allow the 'what-if’s that always pop up. Every roof system is different with vents, chimneys, yada, yada, yada. Brick chimneys are the toughest due to the mortar work.

The trick is to find 10 straight hot sunny days. I like to have 5 more hot days to seal the new roof. That’s why August is the best roofing month. That’s the only time I do roofs. All the other times I’m doing wiring, plumbing, heating, and repairing electronics.

I realize most of you are 365.25 day a year roofers, and I’m sort of an outsider since I don’t need to make a living off of it. I can afford to be picky. A lot of times you guys have a profit/loss and competition to worry about. Here in Central PA, another local roofer went out of business… Roofing Prices are the highest here. Signs of the times. Looks like I’ll be doing more and more of this for desparate people. I’d rather retire.

I’ve also repointed a few chimneys… while I was on the roof (more surface prep).

My biggest pet peeve is the location of the water heater. Most folks put it right next to the load center. I put it in the center of the house, so folks don’t have to wait 3 minutes for hot water. Eights seconds to any faucet is my target. Then there’s the ‘Tankless’ water heaters which are just another scam.

Got any electronics questions? Those are easier.


#13

AVR,

Maybe you should stick to electronics, You apparently don’t know a whole lot about roofing. 5 days to comnplete a job? 3 days to get the roof dried in? 5 hot days in August to get a roof to seal?

While what you call “surface prep” certainly is important, it is not the most critical part of the job. Properly executed flashing details and ventilation are what I would consider to be the most “critical” parts of the job.


#14

Oh boy here we go again


#15

You said it!

Y a w n…


#16

Please, do go on. Tell me your concerns / hypothesis on them 'cause I am very interested in this for a house me 'n the wife will be building “some day”.


#17

try tarping off the chimney , then water test roof only for awhile , then if it dont leak, try water testing the chimney
you may be able to determine origin.
then go from there.

good luck.

gweedo.


#18

When I first heard of Tankless water heaters, I gleefully imagined we’d be getting a small Hot Water Heater under each sink, or for each bath tub. That would be NEAT. We would be saving water, and saving electricity. In addition, there would be only a COLD water line to each room of need, cutting long plumbing runs in half.

Unfortunately, they didn’t turn out so gleeful.

Tankless water heaters draw up to 100 amps to instantaneously heat water on demand. At that much current you would need HUGE wires to run to each appliance, or at best, one to each bathroom or kitchen. Another problem with the milti room scenario is ‘what if’ the two bath and one kitchen units turn on at the same time? Demand of 300 amps on your load center…

Another problem, I don’t know any electricians who want to wrestle those ‘sausage’ 150 Amp power cables through floors and walls (50% overkill for safety) to your remote upstairs bathroom.

So we end up putting one ‘Tankless’ water heater in the basement, next to the load center. As I stated before, this can be the worst place since you may need to run the faucet a long time in some places before you can rinse the soap off the dishes.

Read the fine print on the Tankless Water Heater brochure. Hot water is not INSTANT. It can take 6-10 seconds to get hot water out the side of it. Add this to the length of pipe going to your faucet. If hot water took 20 seconds with a tank heater, it’ll take 30 seconds on tankless.

So they will waste water.

Modern ‘Tank’ heaters have reached the pinnacle of efficiency Glass/foam lined tanks keep the heat in very well. Cycle time for no water flow is only 30 minutes at 15 amps per day (I ran the test myself - .9KW/Hr). They have grossly exaggerated the ‘cost savings’, saying they will pay for themselves in 20 years.

Tankless water heaters are more subject to corrosion than tanked types. In the WORST hard water conditions, tanks will last 3 years, tankless gum up in 6 months. They are more fragile.

And last of all, there is the SURVIVAL scenario. You lose power, water, cable, roads, and phone from some freak hurricane or snow storm. Tanked water heaters will give you a SURVIVAL supply of fresh water to drink and flush the toilet.


#19

And last of all, there is the SURVIVAL scenario. You lose power, water, cable, roads, and phone from some freak hurricane or snow storm. Tanked water heaters will give you a SURVIVAL supply of fresh water to drink and flush the toilet.

Must…refrain…from…sacastic…comments…


#20

Tar: Drink first, flush second.