This repair is continued from Part 1.
Cracked Roof Vent Boot Flashing Repair
I called several roofing companies in my area about the cracked vent boot, but none were available due to the once in 500 year flooding rains that fell on the Atlanta metro area in September. One company said they’d received 600 calls on Monday and most could only put me on a waiting list for a call back. I was quoted $125 to install lead pipe flashing for labor and materials, but no one could promise when they could get to it.
I was able to buy an Oatey Galvanized Base No-Calk® Roof Flashing at Lowes for about $7 that fit a 2″ inch vent pipe. I would have preferred a lead pipe flashing because it’s the best and longest lasting flashing solution that avoids the problem of cracked rubber boots. I can always hire a roofer when they’re not so busy and have lead flashing installed.
Oatey Galvanized Base No-Calk® Roof Flashing
Roof Vent Flashing Installation
Removing the old roof vent and installing a new one is simple:
- Pry up the roofing nails used to attach the old flashing.
- Gently lift up the shingles above the flashing.
- Lift the flashing off the vent pipe.
- Slide the new flashing over the vent pipe.
- Tuck the uphill part of the flashing under the shingles.
- Fasten the new flashing with galvanized roofing nails.
- Apply a dab of roofing sealant to the nail heads and bottom tabs of the shingles that were disturbed.
The entire job takes less than 15 minutes. It seems easy and it is, unless you have a high and steep roof like mine. A 40 foot ladder is necessary to reach the roof from the ground and I’m not comfortable working so close to the edge of the roof. Time to hire a professional roofer, but none were available on short notice. What to do?
I got lucky and noticed a roofing crew working in the neighborhood. I asked the foreman if I he could install the new vent flashing. He said they were almost finished with the current job and could send someone over in 45 minutes. He asked if I had the new vent flashing, I said yes and showed him the Oatey No-Caulk flashing. He said he would install my flashing and add a rubber rain collar for extra protection for $50.
Two men from the roofing crew a short while later as promised. They setup a 16 foot ladder by the garage and bear crawled up the hip ridges with a big block of foam rubber (i.e. an old couch cushion) wearing regular tennis shoes with amazing agility! Compare this to my Poor’s Man’s roofing shoes in this article. In this photo the roofer is getting into position to start work.
Roofer Bear Crawling along the Roof Hip
The roofer has pried up the nails and is removing the old vent pipe flashing. The block of foam rubber grips the roof so he doesn’t slide off. The new flashing is tucked under the edge of shingle above him so it’s doesn’t slide away.
Removing the old Roof Vent Pipe Flashing
The new flashing is slide over the pipe, tucked under the shingles on the high side, and nailed to the roof.
BASF SONOLASTIC® NP 1 roof sealant is applied to the nail heads and bottom tabs of the roof shingles that were raised to install the flashing. This makes everything waterproof and ensures the shingles are glued to the next row so they won’t be lifted by the a strong wind.
Roof Sealant is Applied to the Nail Heads
Rain Collar – Leak Even While Raining
Rain & Repair Pipe Collars are simply the rubber boot without the metal flashing. It acts like an umbrella to shed water over a cracked boot. A rain collar costs $5 to $10 and can be installed while it’s raining or wet for an emergency fix. No caulking, it stretches over the pipe for a water tight seal.
This is the new roof vent flashing with an added rain collar for extra protection.
New Plumbing Roof Vent Flashing with Rain Collar
Cracked Vent Boot Inspection
The boot on the old Oatey all-plastic vent flashing was severely cracked/split in the places. This broke the watertight seal around the 2″ PVC vent pipe and allowed rain water to leak in and run down the vent pipe onto the drywall ceiling. This vent boot failed after about 10 years on the southern exposure of the roof.
Oatey – Cracked/Split Boot on Vent Pipe Flashing
A side view of the old vent flashing:
Oatey – Cracked Plumbing Vent Boot Flashing
I may have all my vent boots replaced with lead flashing when the roofing companies are less busy in a few months. Lead flashing lasts practically forever and almost never leaks because the rim of the lead flashing is folded into the top of the plastic vent pipe for a 100% seamless and waterproof installation. The rubber vent flashing costs $7 compared $30 for a lead flashing. The reliability of lead flashing is well worth it in my opinion… unless you have squirrels because they like to chew on the soft lead flashing.
Take care,
Bob Jackson
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Thank You for this information. I’m no roofing expert..well..I know a heck of a lot more now thanks to your pictures and links. The Rain Collars are great. It was impossible to purchase them locally in my City of Austin, Texas. Nobody stocks them! What A Quick Fix. Thank You Again. Johnny Goyen Austin, Texas
If a rain collar isn’t immediately available, you can always cut out the rubber boot from a standard flashing and slide it over the vent pipe to cover the cracks in the old boot.
Thanks,
Bob Jackson
My old boot looked like it was melted and separated from the plastic pipe just enough to leave a space for rain to enter. I was able to remove the rubber boot from a new aluminum flashing by pulling it out of the channel it’s tucked into. If you pull hard enough it will come out. I cleaned the deteriorated rubber from the old boot with a putty knife and sandpaper and siliconed the gap on the old boot for added protection. I applied a little dish detergent to the plastic pipe to make the rubber slide on easier and slid the new rubber boot on without the metal flashing creating a little “umbrella” directly over the existing boot. A quick fix that should last for as long as the new rubber boot lasts for less than $7.00.
Yes, that will work. You’ve made a field-expedient rain collar and avoids removal of the old boot flashing.
I just repaired 4 leaky roof vent pipes. I used the plastic oatly roof vents I got from home depot $7 per piece. There was nothing wrong with the existing flashing. I simply cut out enough of the new piece and slid down over the existing flashing. I used a little ‘Roof Jack’ petroleum based asphalt sealer on the top of the old one, so when I pressed the new piece that I made it would have something to adhere to. What I didn’t realize is the in small words on the new Oatly vent flashing, which is made of all plastic and softer rubber to seal around the pipe, are words that say ‘Petroleum Based Sealants should be avoided’ Do I have anything to worry about? Will this type of sealant cause any harm to the plastic/rubber?
I’ve seen roofers do exactly what you describe – it’s quick, inexpensive and avoids disturbing the shingles when a proper rain collar isn’t available or the weather is cold and the shingles may crack.
The petroleum-based sealant can attack the vent boot rubber. Check it in a week and again in a few months. I doubt it will crack immediately but will probably shorten the lifespan of the boot. Pick a warm day next Spring to replace the entire boot and add a rain collar.
Thanks Bob,
Certainly will do as you advise.
Your post is very useful. The roofer that I hired used DAP® ALEX PLUS® Acrylic Latex Caulk Plus Silicone to seal the nail and gap between new vent boot and the pipe since he had to tear off the inner ring to fit in the pipe. Is this type of sealant sufficient enough?
Roofing applications are not listed in the “Suggested Uses” section of the DAP® ALEX PLUS® Acrylic Latex Caulk Plus Silicone technical bulletin.
Whereas the SONOLASTIC® NP 1™ data sheet states under the “Where to Use” section (partial list follows):
* Roofing
* Wastewater treatment plants
* Dams
* Spillways and storm drains
* Wetwells and manholes
* Interior and exterior
* Above and below grade
* Immersed in water
* Clay & concrete roof tiles
A key product spec. in my opinion is the “Joint Movement Capability“:
* +/- 35% for the BASF NP1
* +/- 12% for the DAP ALEX PLUS
because roofs expand and contract a lot between the cold nights and roasting hot sunny days.
Given that the DAP ALEX PLUS product is not specifically rated for roofing applications and the wide variety of high performance roof-rated caulks available at roofing supply stores, I’d be disappointed with your roofer.
Thanks Bob! Do you have any suggestion? Should I have him come back to take out the DAP Sealant and reapply the Sonoplastic NP1 to the nail heads?
He did apply the TAM-PRO PREMIUM SBS (http://www.tamko.com/Cements-Coatings/TAM-PRO/ProfessionalMastics-Cements-SBSAdhesives/Q-20PremiumSBSFlashingCementTube) under the bottom tab of those shingles that were raised to install the flashing.
I did ask him to apply the TAM-PRO Premium SBS to the nail head as well but he said the DAP sealant is good enough.
I’d have the roofer come back out, scrape off the DAP ALEX PLUS and reseal the nail heads. A dab of the TAM-PRO PREMIUM SBS Q-20 asphalt flashing cement on the nail heads would’ve been OK, so I wonder why he used DAP instead?
The risk with the DAP caulk is it may peel or crack after a couple of seasons, but it’s not like it’s an emergency. It’s more about a doing a quality job and using materials that have comparable service lives. If rain water worked it’s way around the nail head, what’d you see is a water stained area under the roof deck from inside the attic, which could over time deteriorate as the glue in the OSB or plywood deck failed. If you had your roof reshingled down the road, the next roofer would say that section of roof deck needs to be replaced for an extra charge.
I couldn’t find the Sonalastic sealant at the local store. I might order it online but that will take time. Can I substitute it with DAP® 3.0™ Advanced Blacktop & Roof Sealant with Kwik Dry® Technology (http://www.dap.com/docs/tech/00010054001.pdf) being sold at Home Depot?
For the DAP sealant, that can be scraped off even after more than a week after it was applied since the roofer prob can’t make it back till the coming weekend?
The DAP 3.0 Roof Sealant will be fine for sealing the nail heads.
> For the DAP sealant, that can be scraped off even after more than a week after it was applied
> since the roofer prob can’t make it back till the coming weekend?
A property of silicone & latex caulks is they are easy to scrape or rub off even when cured. Scrape off what you can with a small putty knife, the rest will rub off with your thumb. You need a clean surface for the roof sealant to adhere directly to the flashing.
Finally got roofer back to redo the job. Beside having him sealing around the edges of the boot, I also have the roofer apply the Sonalastic sealant between the area where the plastic part of the boot made contact with the vent PVC pipe as extra precaution. Will that be a problem? Does the chemical in the sealant cause any damage to the PVC pipe? Thanks!
> I also have the roofer apply the Sonalastic sealant between the area where the plastic part
> of the boot made contact with the vent PVC pipe as extra precaution. Will that be a problem?
It wasn’t necessary to apply sealant there. The boot is designed to hug tightly around the vent pipe to make a watertight seal. The sealant won’t prevent the boot from cracking over time due to UV light damage from the sun. The rain collar is your best protection *in addition* to the boot. The rain collar “floats” freely as it’s only attached to the vent pipe, experiences no stress due to heat contraction/expansion of the roof and shields the vent boot from UV damage.
> Does the chemical in the sealant cause any damage to the PVC pipe?
The sealant won’t bother the PVC vent pipe. PVC is very resistant to most chemicals.
Good article on replacing the flashing. I currently have lead flashings, but squirrels have chewed on them to the point where rain is getting through. Considering the Oatey. Any suggestions on which is better in this circumstance? Really don’t want to spend the money on lead flashings if in a year those rodents are going to chew through them again.
Thanks
I have lots of gray squirrels that come up to the house all the time for the bird feeder. They’ve never bothered the plastic vent boots or PVC vent pipes. My guess is they like the soft lead flashing on your roof.
You might try SquirrelGard™ – the product literature looks very convincing.
Thank you so much for posting! We have a 7 yr old roof that I recently discovered was leaking around not just one ventilation pipe, but 5! I don’t believe there was ever a boot type flashing put around the pipes from looking at the roof from outside, but that may be b/c the texas heat will melt them! I bought some of the “as seen on tv” flex seal and have considered putting that around the pipe from the inside, but not sure if that will keep the water out and/or cause more damage if the water has a place to pool up. It is not a big flow of water, its like a trickle but I can see daylight from the attic all around the pipe, so something is insulating, but not installed properly I am guessing. It seems we don’t get just a normal rain storms either…its 9 inches in a day or drought!! I keep asking my husband to fix this…I think we need to have a professional take care of it – the towel solution only goes so far! Of course, he is out of town and it rains heavily – murphys law!!
Funny… didn’t think anyone else would be using the knotted towel technique!
Perma-Boot is a quick and simple DIY solution for leaking vent pipe flashing. I just had my roof replaced due to hail damage and installed these over the new vent pipe flashing as extra long term protection. My roofer said Perma-Boot works well and recommended the product. Cost is ~$19 and they’re available at Home Depot.
Bob,
Have you ever heard of rain water that goes down a vent pipe leaking out? What are the odds of the pipes elbow joint simply coming loose after 20 years and allowing rain water to leak out? This is what my roofer is suggestion.
I assume your roofer inspected the pipe boot on the roof and looked at the roof deck from inside to attic to confirm there’s no leak? Did the roofer replace the pipe boot or install a Perma-Boot just to be sure?
It’s not unreasonable the vent pipe could have a leak at the elbow, however the elbow is also where water would drip off the outside of the pipe if the problem is with the vent boot on the roof. Do this to identify the leak source: Wrap the vertical part of the vent pipe above the elbow in a single layer of toilet tissue as a tell-tale, then secure it with a piece of tape. Place a pan under the pipe elbow with a piece of toilet tissue in the pan.
Check the tell-tales during or after the next rain shower. If the tell-tale wrapped around the vent pipe shows signs of being wet, then water is running down the outside of the pipe from the roof and you have a bad vent boot. If the upper tell-tale is dry and there’s water in the pan, then the pipe elbow is leaking. A PVC pipe elbow is easy and inexpensive to replace.
Thank you for this!! I am in ATL and after the last weekend of rain, I have discovered a leak in the roof where the bathroom vent is – very similar to the situation you described. There is no way I’d be able to do what you suggested by myself. But I’ve been getting crazy quotes, from $300 to $500 to $1250. I know it’s not a huge job, but am having trouble finding a reputable roofer. Do you have recommendations for the ATL area?
Thank you again!
Call Dr. Roof at 770-552-7663 for repairs in the Atlanta metro area.
$300 to replace a cracked pipe boot could be reasonable because a small job just to replace the boot may incur the minimum repair charge.
On the other hand $1,250 could be warranted if the pipe boot leak caused the roof deck to rot necessitating a major repair to tear off the shingles, replace the rotted section of deck, install new felt and shingles. Can you inspect the roof deck around the vent pipe from inside the attic?
Wow! Such a speedy reply. Actually, I think the decking has to be replaced because there’s a spot that is black (mold?). I think it’ll be about a 3 square foot piece that needs to be removed, then resealed, then shingles replaced. I had two roofers come out to look and this is what both said. One was at $500, the other $600. So I’m pretty sure this is the problem. I figured I ought to have a couple more quotes, and called a few places with this description. That’s where the $350 and $1250 quotes came from –just over the phone. I’m learning a ton as I go through this, but just don’t trust my decision-making completely. Your site is incredibly helpful to at least learn about how houses work! Thanks again.
> I think it’ll be about a 3 square foot piece that needs to be removed, then resealed, then shingles replaced.
Beware of a “patch” between only two rafters versus the better practice of replacing a section of deck that spans at least 3 rafters for strength and durability.
If you’d like to learn more about roofing work, see these posts for a full roof replacement including reworking the pipe vents, flue vents and rotted sections of roof deck:
* Hail Damaged Roof Replacement: Part 5 – Plumbing Vents
* Hail Damaged Roof Replacement: Part 7 – Rotted Roof Deck Repair