Comp shingles on 2:12 to less than 4:12 pitch.

Pablo is also my favourite go to shingle over the years. More so the past few years as they are packaged 4 to a square and are easier to handle in my old age :) I believe they have kept the same colour blend for the past 25 years where as other manufacturers seem to change theirs up every 5 years or so. They also are very accommodating with warranty claims. Had dealt with a few of their late 80's HO25 cracking issues and the homeowners received full material credit. Goes a long way in my books when a company takes ownership for a mistake without putting up a fight.

egg: I was looking at the specs on the Pabco Radiance and they say they reflect 28% of solar rays. Question: Do you feel any of that heat being reflected back on you when installing them?

seen-it-all:

Not like the radiated heat you feel when you hold up a space blanket next to your face. I'll have to pay better attention next time. Has to be something though.

What I'm thinking...conductive heat is what burns your butt when you sit down on red-hot shingles and convective heat is what you see when you put your head down next to the roof and look down the line at the heat waves coming off the surface. Both of those heat types are the result of heat gain in the comp looking for a way out and neither of those are nearly as radical as for other, regular comp. You also don't get bundles heating up under the topmost bundle in a stack and you don't have to peel them apart because they don't get nearly as limp and sticky.

I'm sure the radiant energy that isn't reflected causes the heat gain there is, but the radiant energy that is reflected never shows up as heat because it only turns to heat when it "lands." Travelling through space it has no heat. The radiant comp just sends it off down the road to strike something else.

So.....Does all radiant energy get absorbed somewhere once it enters the earth's atmosphere? I'm not a scientific type of guy but sometimes things like this intrigue me. If you say that the radiant energy reflected keeps going somewhere to find a place to land, would that place be my shady side facing the roof surface? Something akin to getting a sunburn off of reflected snow when skiing or out on the water when fishing. I've been barbecued a few times out on the boat even though I've been in the shade of the canopy all day.

I remember asking about red roofs reflecting more radiant energy than any other colour a few years back. I also found red shingles tended to last longer than other colours.

I'm not what you call a scientific type of guy either but I pay attention as well as I am able as often as I am able. I've got a scientist daughter who sometimes gets annoyed with my tactile-based sensibilities but she has never given up on me entirely cuz I do try. lol.

I ran across this explanation recently which I found helpful and hope is accurate.

http://www.radiantbarrier.com/physics-of-foil.htm

I believe the sunburn/snowburn is caused by UV (related but different and far nastier)

The problem for us unscientific types is we can't actually see infra-red, ultra-violet, radio, or any other type of electro-magnetic energy. Microwaves aren't hot but they get things hot. While we're out there pounding nails a lot of other folk are making a living off of this stuff. I would say it behooves us to stay, or try to stay, within sight of what they discover. It certainly does affect us and with the newer building standards and building science, it impacts our reputations big-time if we ignore it all.

anything less than 3 I recommend 3 tab with double layer 15# felt. Someone mentioned malarkey and I have and I had been tempted to use them since they have a tapered edge. That confirms what I was thinking so may start giving those a shot for customers who still want dimensional on lower slopes. Also, don't know what it's like in your area, but most companies are using synthetic felt now and some brands stat right on them that they are not to be used in less than 4/12 pith. I must be the only one in my area that double laps traditional felt and stays away from synthetic in those applications.

I'm kind of in the same boat there, but I increase the setbacks and use stainless nails and even on laminates have had no problems with any of the underlayments, either synthetic or rag felt. My biggest issue is with composted leaf debris. Much as I like it, rag felt rots.

That was an interesting article on the radiant energy. A good day is when you learn something new that gets your mind working. I'm considering doing an exterior refit on my house and was looking at the radiant insulation but after reading the reviews about the product I don't know if it's worth the money.

Do they make a radiant vest to keep you cool in the summer and warm in the winter. Maybe that's what those ETs wear. 😀

Atlas has an 1.5 inches on their lamination and I have been using ever since they went that way, I love that fact. With our recent 30 inches of rain in 50 hours event, ive had a few that water travelled from the butt joint to the closest fasteners and leaked I found it to be due to aggressive sealing of the shingle also. The duration has a deflection in their nail line that will cause water to travel to the fasteners wouldn't use them under a 6/12 pitch. if you run your finger across it you will feel it, it is a water diverter guaranteed