Thread: Vinyl Siding Buckling

I know that this topic has been covered with respect to heat reflected by windows, but this one seems to be different. I'm looking at some siding damage that appears to be due to heat from a direct vent boiler. The windows on the neighboring house have not been changed recently, which would seem to rule them out as the cause . The damage occurred within 1-2 years after the boiler was replaced and the direct vent was installed. The siding damage is directly above and to the side of the vent. The vent would seem to be the culprit, but I've never heard of this being an issue. The exhaust is only about 78 degrees F. The siding about 30 years old and it's brittle, so I'm thinking the age of the siding might be a contributing factor.
Any thoughts?

Originally Posted by Steve Frederickson

I know that this topic has been covered with respect to heat reflected by windows, but this one seems to be different. I'm looking at some siding damage that appears to be due to heat from a direct vent boiler. The windows on the neighboring house have not been changed recently, which would seem to rule them out as the cause . The damage occurred within 1-2 years after the boiler was replaced and the direct vent was installed. The siding damage is directly above and to the side of the vent. The vent would seem to be the culprit, but I've never heard of this being an issue. The exhaust is only about 78 degrees F. The siding about 30 years old and it's brittle, so I'm thinking the age of the siding might be a contributing factor.
Any thoughts?

I would rule out the boiler exhaust for two reasons; 1) the distance the damage goes from the vent would require a large volume of hot air, 2) the damage is below the vent and heat rises.

Looks like they might have kept a grill too close to the siding?

Vern

Thanks for the input. The photos might not be clear, but the damage is to the side and above the vent. I could see the exhaust, and it was following the same pattern as the damage to the siding.
I tend to agree that the exhaust is not hot enough. Maybe moisture from the exhaust getting behind the siding, freezing, etc. I don't know I'm stumped

Originally Posted by Steve Frederickson

Vern

Thanks for the input. The photos might not be clear, but the damage is to the side and above the vent. I could see the exhaust, and it was following the same pattern as the damage to the siding.
I tend to agree that the exhaust is not hot enough. Maybe moisture from the exhaust getting behind the siding, freezing, etc. I don't know I'm stumped

While most of the damage is above and to the side, some is below the vent. I have never seen moisture cause that type of damage. Along with the reflection from a window theory, they could have been using a grill or had a generator in that area?

I don't think that's a direct vent boiler, but rather a condensing boiler.

I vote for gas grill or a bored teenager playing with a plumbers torch....

Originally Posted by Dom D'Agostino

I don't think that's a direct vent boiler, but rather a condensing boiler.

I vote for gas grill or a bored teenager playing with a plumbers torch....

I really doubt it's from a gas grill. The driveway is only 9' wide. There's really no room for a grill and a car. Also, the homeowner was there and he had no reason to lie. I was there to investigate an insurance claim. If it was damage from a grill, it would be to the owner's benefit to admit that

Originally Posted by Vern Heiler

I would rule out the boiler exhaust for two reasons; 1) the distance the damage goes from the vent would require a large volume of hot air, 2) the damage is below the vent and heat rises.

I suspect that it is the exhaust vent for two reasons: 1) the pattern matches how that hot air would flow, 2) most of the damage is at or above the vent and heat rises ... and as it exits the vent it would also migrate downward to some degree - I've seen hot air exhausting from vents and it does not all immediately go vertical.

Originally Posted by Jerry Peck

I suspect that it is the exhaust vent for two reasons: 1) the pattern matches how that hot air would flow, 2) most of the damage is at or above the vent and heat rises ... and as it exits the vent it would also migrate downward to some degree - I've seen hot air exhausting from vents and it does not all immediately go vertical.

So why isn't the vinyl vent pipe melted?

Originally Posted by Vern Heiler

So why isn't the vinyl vent pipe melted?

Because it is PVC, which is more resistant to heat than vinyl siding is.

Originally Posted by Steve Frederickson

Also, the homeowner was there and he had no reason to lie. I was there to investigate an insurance claim. If it was damage from a grill, it would be to the owner's benefit to admit that

Relax, it was tongue-in-cheek...

Curious, why would it benefit the homeowner to admit he burned the siding? (Not saying he did, but I don't follow the logic.)

Maybe there's something wrong (intermittently) with the boiler.

Originally Posted by Jerry Peck

I suspect that it is the exhaust vent for two reasons: 1) the pattern matches how that hot air would flow, 2) most of the damage is at or above the vent and heat rises ... and as it exits the vent it would also migrate downward to some degree - I've seen hot air exhausting from vents and it does not all immediately go vertical.

Why did all the heat go to the right?

Originally Posted by Vern Heiler

Why did all the heat go to the right?

It probably didn't ... there is a door to the left and it survived better than the vinyl siding to the right.

Just like above the exhaust tee - no damage as the heated air had dissipated enough into the outdoor air by the time it was above the top of the tee to not cause the damage.

The PVC pipe is thicker than the vinyl siding and can thus dissipate and handle the heat better than the quite-thin vinyl siding can.

Maybe heat from the exhaust of a vehicle warming up in the driveway?

Originally Posted by Vern Heiler

Why did all the heat go to the right?

Probably due to prevailing winds. When I was there, I could see the exhaust and it was following a pattern exactly like the damage to the siding.

My guess is a gas grill and the warped pattern fits that pretty well, and have seen similar. There would have to be some serious heat blowing out of the exhaust to warp the siding. I believe vinyl starts to soften around 160 degrees Fahrenheit, which is pretty hot and I would imagine a different vent and possible location would be required at those temps.

Even PVC (Sch 40) itself is only rated to about 140F, so it would be showing signs of warping if the siding is getting that hot.

I'm not saying I'm correct, but just trying to help with the detective work. If the siding to the far right is warped wouldn't the vented exhaust be 200F+ to allow for cool down 3-4 feet away with a horizontal blowing wind? Heat wants to rise ASAP.

I'm thinking gas grill as the heat would push to the side a bit then rise up, pyramid style, like in the photo, getting smaller towards the peak until it dissipated.

As far as the owner, people don't like admitting to stupid...

Originally Posted by Dom D'Agostino

Relax, it was tongue-in-cheek...

Curious, why would it benefit the homeowner to admit he burned the siding? (Not saying he did, but I don't follow the logic.)

Maybe there's something wrong (intermittently) with the boiler.

If the owner caused the damage, the insurance company would probably pay (they usually insure against stupidity). If the problem is due to normal aging, they generally wouldn't pay.

Originally Posted by Jerry Peck

Because it is PVC, which is more resistant to heat than vinyl siding is.

My original thought was that it was heat from the exhaust, because the pattern on the siding matches exactly with the pattern that the exhaust could be seen exiting the vent. but the temperature of the exhaust is only 80 degrees.

My next thought was that it possibly was not due to heat from the exhaust, but moisture from the exhaust, which is finding its way behind the siding and freezing. You can see some icicles at the bottom of the siding, but I don't know if ice could cause siding to warp/buckle. Maybe it could be due to differences in temperature between ice behind the siding and the warm exhaust air on the exterior of the siding. The siding is very old and brittle (30+ years old) so I was thinking that might be a factor.

It it's due to the exhaust temperature, I would think this would be a widely reported problem, but I've never seen r hear about this being a problem.

Originally Posted by Mike Kleisch

Even PVC (Sch 40) itself is only rated to about 140F, so it would be showing signs of warping if the siding is getting that hot.

I believe the reason that the PVC is okay is that, first of all, it is thick enough to resist the heat, and secondly, that the furnace is only running when it is cold outside which helps protect the PVC from getting too hot. The vinyl siding, being much thinner, would heat up much quicker and is also of a formulation which is more flexible than that used for the PVC pipe, thus likely to be more susceptible to distortion from heat.

That's my story and I'm sticking to it ... (until more information comes forth and causes me to change my mind ).

Originally Posted by Steve Frederickson

The driveway is only 9' wide.

There's really no room for a grill and a car.

Whats shown is Pryor damage.,

Small driveway with car glass reflective heat done during the Summer months.

Originally Posted by Billy Stephens

Whats shown is Pryor damage.

I like that one, Billy, the new owners can say "Oh that? That was was like that when we bought the place, that is Pryor damage." That's way .

Originally Posted by Jerry Peck

I like that one, Billy, the new owners can say "Oh that? That was was like that when we bought the place, that is Pryor damage." That's way .

We were talking about the cause of the heat damaged vinyl siding ( not the "New Owners.")

Summer heat makes a lot more sense than furnace exhaust.
*if the exhaust was hot enough for the damage shown it would be blowing flames.

It's all a SWAG......


My swag is that a non condensing boiler (direct vent) was installed at one time and it caused the damage before the new condensing unit was installed.

I like the car and reflected light theory!

With 78f degree exhaust temp the condensing boiler is not the culprit. If that was the case we would have melted siding on every home in the country.

Do they have a gas dryer? Looks like a dryer vent below the PVC vent pipe.

Originally Posted by Billy Stephens

We were talking about the cause of the heat damaged vinyl siding ( not the "New Owners.")

You mean you didn't come up with that 'Pryor damage/Pryor condition' intentionally? I feel soooo let down, man.

What's the difference between Pryor and Pyro? Someone forgot to spell check ...

Originally Posted by Jerry Peck

You mean you didn't come up with that 'Pryor damage/Pryor condition' intentionally? I feel soooo let down, man.

What's the difference between Pryor and Pyro? Someone forgot to spell check ...

The funny thing is I thought this was going down the road of this was "Richard Pryor's home and he caused the damage" joke, because, well, Billy is clever, and Richard Pryor set himself on fire at one time...

I'm guessing it was supposed to be "Prior" vs. "Pryor" as I follow the thread now, or I just goofed up a joke in the brewing...

Originally Posted by Jerry Peck

You mean you didn't come up with that 'Pryor damage/Pryor condition' intentionally? I feel soooo let down, man.

What's the difference between Pryor and Pyro? Someone forgot to spell check ...

Someone has way over thought this.
Please reply spell check error with red lines,throw in a few circles ,arrows and maybe a graph on how 78degree exhaust in the winter buckles and distorts the cladding several feet away.

Ask if the neighbors have had their windows replaced recently
It can be the reflected light form the adjacent homes windows!

Originally Posted by Steve Frederickson

The windows on the neighboring house have not been changed recently, which would seem to rule them out as the cause .

Originally Posted by Jeff Zehnder

Ask if the neighbors have had their windows replaced recently
It can be the reflected light form the adjacent homes windows!

1st Post OP Said No.

Missed that post in my haste!

Originally Posted by Jeff Zehnder

Missed that post in my haste!

Been there.

Not a home inspector nor do I work in HVAC, but I have a couple of ideas that may bear investigating.
That the escaping gas condenses on the siding is shown by the icicles in the photos. If the vent is from a condensing boiler (probable because of the low exhaust temp and the plastic pipe for the exhaust), I believe the flue gas and the condensate is acidic. Not dangerously, think grapefruit juice. But, could warm acid warp vinyl siding over time? Particularly old siding?
There may be other chemicals in the gas as well, I don't know.
I note that the visible hinge of the door near the vent is corroded much more than I would expect, which supports this chemically-based-damage theory.

Another thought is that if the gas is warm and emitted intermittently, the siding is allowed to get quite cold along it's length, then warmed in a small area, then allowed to get cold again, then warmed in the same small area...
Over time the repeated expansion and contraction of the siding in only those warmed area could lead to warping, even if the temperatures are never outside the acceptable range.

Originally Posted by Steve Frederickson

If the owner caused the damage, the insurance company would probably pay (they usually insure against stupidity). If the problem is due to normal aging, they generally wouldn't pay.

Unless the damage was intentional, the insurance company will (generally) pay, subject to the home owner's deductible.