Roof color

[JohnRoberts]

I have long joked that if I were king, I would make everybody paint their roof white in the summer and black in the winter.  Since every man is king of his own castle when I replaced my leaky roof I decided to take my own advice.

Now after less than a week of living under my almost white (ivory) roof, the house is definitely cooler and air conditioner is not working so hard (my old roof was traditional black asphalt shingles.... so very hot in summer.).

An unintended consequence is that my indoor humidity bumped up slightly from the air conditioner running less (still low 40s because I manage humidity too).

JR

PS: Being cheap, I wrestled with the option of a bare tin (galvalume) roof, since that would reflect sunlight, but would be a little too redneck (look like a barn), for even me. 

 

[pucho812]

I've been in a tin roof house,  it was noisy when it rained.

 

[JohnRoberts]

I've been in a tin roof house,  it was noisy when it rained.

It rained hard today and not noticeably noisier than the old roof...

Tin roof on top of an empty space is noisy, and can be heard from a distance, but I live in a house, not a barn. So metal roof on top of old shingles is pretty quiet. 

I notice that the channels in the metal roof send water shooting almost a foot away from the house, not just dripping straight down like the old shingles did. This will change how my yard behaves, near the foundation... I am still thinking of adding gutters (it rains in MS). 

So far not one single regret, other than waiting so long.

JR

 

[abbey road d enfer]

I have long joked that if I were king, I would make everybody paint their roof white in the summer and black in the winter. 

Very nice thinking, John.
I would also ban black cars.

 

[scott2000]

I notice that the channels in the metal roof send water shooting almost a foot away from the house, not just dripping straight down like the old shingles did. This will change how my yard behaves, near the foundation... I am still thinking of adding gutters (it rains in MS). 

So far not one single regret, other than waiting so long.

JR

That's nice..... How much did that cost?  I've never looked into the pricing of them but know they aren't cheap......

If you do get gutters, make sure to check they don't goof the pitch towards the downspouts or set the gutters too low....Can't tell you how many times I've seen that and the water still shoots right over in a good storm or the water just sits in them......That and the anchoring set to low where the water level in the gutters will leak in those spots.... I'm sure there are systems that address this any how.... Most of the hokey ones I've seen are older....

Very nice thinking, John.
I would also ban black cars.

I've got a black suv and when I gutted it, I put that foil bubble insulation on the roof and floor board before putting back the headliner and all the carpet and it stays surprisingly cool ,,,, That stuff works really well.....

I actually have it on my garage door panels too and it makes a huge difference....

 

[Gene Pink]

I have long joked that if I were king, I would make everybody paint their roof white in the summer and black in the winter. 

Hmmm, one foot wide flaps that are black on one side, and white on the other, that cover the roof. Linkage connecting these together like an AC vent outlet. Handles hanging down every 10 foot, to manually flip them seasonally.

Or use servo motors to automate, and let some computer figure it out.

Gene

 

[abbey road d enfer]

I've got a black suv and when I gutted it, I put that foil bubble insulation on the roof and floor board before putting back the headliner and all the carpet and it stays surprisingly cool ,,,, That stuff works really well.....

The way it works, it actually increases the thermal resistance between the outer boundary (the paint coat) and the inside. This increases significantly the time-constant of heat transmission, from a couple of minutes to a couple dozen, so when you take your vehicle from a shady area to the open, you'll feel the heat maybe 20-30 minutes later instead of 2-3. If you do a lot of small hops, it really works, but for a long trip, the heat inside will be the same. The only way to really minimize A/C operation is by decreasing the amount of captured heat, i.e. reflecting it; that means painting the car in a light hue, such as white or light silver, even chroming the whole body.

 

[Youngwhisk]

I have been in the roofing supply business for over 30 years.

The colour of the roof does make a difference, however with adequate ventilation the transmission of heat can be significantly reduced. Ventilation inflow and outflow is required above your insulation . If you are missing one of those then you have minimal or no ventilation. Continuous ridge venting has become much more common. You also need to have enough insulation in your attic no matter if you are dealing with heat or cold.
Where I live in Canada, the roofs are all white from snow for approximately four months per year.

 

[JohnRoberts]

Hmmm, one foot wide flaps that are black on one side, and white on the other, that cover the roof. Linkage connecting these together like an AC vent outlet. Handles hanging down every 10 foot, to manually flip them seasonally.

Or use servo motors to automate, and let some computer figure it out.

Gene

Painting roofs could be good make work for a future generation of unemployable kids. If painted twice a year, the roofs would probably never need to be replaced.

Of course I am not king....

JR

PS: Elon Musk's solar shingles make sense, but a lot more expensive than painted galvalume.

 

[JohnRoberts]

That's nice..... How much did that cost?  I've never looked into the pricing of them but know they aren't cheap......

Less than $7k total including some earlier water damage repairs to soffits et al before the roof job.  I suspect the coated metal panels cost similar amounts in different regions, but labor is a huge variable component in a roof job so I benefited from reasonable labor costs here in nowhere MS.  Two men and one gofer/helper took about a week.  In the real world that would probably cost me a bunch more.

If you do get gutters, make sure to check they don't goof the pitch towards the downspouts or set the gutters too low....Can't tell you how many times I've seen that and the water still shoots right over in a good storm or the water just sits in them......That and the anchoring set to low where the water level in the gutters will leak in those spots.... I'm sure there are systems that address this any how.... Most of the hokey ones I've seen are older....

my roof guy suggests the continuous gutter systems that they make on site (he doesn't do them). Looking at how far the water shoots away from the roof, the gutters probably need to be different.  For now the water will already land further away from my foundation than it was before.

I've got a black suv and when I gutted it, I put that foil bubble insulation on the roof and floor board before putting back the headliner and all the carpet and it stays surprisingly cool ,,,, That stuff works really well.....

I actually have it on my garage door panels too and it makes a huge difference....

yup insulation matters... If I was king there would be more insulation in houses too.

JR

 

[Gold]

In the garden shed I use as a cabin I insulated it with foil faced rigid fiberglass. It made a huge difference. It stays pretty cool the summer and sips propane in the winter even in sub zero temperatures.

I just got another shed which is becoming the kitchen. That rigid fiberglass is expensive so this time I’m going to use foil sheets and then blue styrofoam of which I bought way too much of. I know styrofoam is toxic when it burns. I’ll cover it with something non combustible over the stove.

 

[JohnRoberts]

In the garden shed I use as a cabin I insulated it with foil faced rigid fiberglass. It made a huge difference. It stays pretty cool the summer and sips propane in the winter even in sub zero temperatures.

I just got another shed which is becoming the kitchen. That rigid fiberglass is expensive so this time I’m going to use foil sheets and then blue styrofoam of which I bought way too much of. I know styrofoam is toxic when it burns. I’ll cover it with something non combustible over the stove.

Yup, that sounds a little like what I wrapped around my smoker to help the puny electric hot plate get the temperature up high enough.

I made a foil covered styrofoam tent/cover for my slow cooker so it doesn't waste heat heating up my kitchen. Probably uses less electricity too....

JR

 

[abbey road d enfer]

The colour of the roof does make a difference, however with adequate ventilation the transmission of heat can be significantly reduced. Ventilation inflow and outflow is required above your insulation . If you are missing one of those then you have minimal or no ventilation. Continuous ridge venting has become much more common. You also need to have enough insulation in your attic no matter if you are dealing with heat or cold.

Indeed, as anyone who's ever designed power amps, there are conduction, convection and radiation. You could add forced-air and heat pump. Each has its own properties. They all can be used together. As always, the choice is guided by whatever constraints.
Anyway, starting with minimizing heat ingress makes sense to me.

 

[JohnRoberts]

I have been in the roofing supply business for over 30 years.

The colour of the roof does make a difference, however with adequate ventilation the transmission of heat can be significantly reduced. Ventilation inflow and outflow is required above your insulation . If you are missing one of those then you have minimal or no ventilation. Continuous ridge venting has become much more common. You also need to have enough insulation in your attic no matter if you are dealing with heat or cold.
Where I live in Canada, the roofs are all white from snow for approximately four months per year.

Indeed...  I have attic vents and even an attic fan, that I haven't used for years because it sucks small bugs into the house, through the screens, that mature to full sized bugs indoors.  :'(

I have access to attic, and crawl space from my laundry room and I have half considered pulling attic air down under the house in the winter, and crawl space air up to the attic in summer... This is on my "maybe" to-do list but pretty low on the list.

JR

PS: I have one patent for amplifier heat sink design so I grok heat flow (at least a little).  8)

 

[living sounds]

Looks pretty cool.  8)

I live under a roof that was insulated to German 2016 standards, so there's half a meter or so of insulating material between the roof and the ceiling (same goes for walls). It's black, but the heat seems to come in only through the windows, walls and ceiling are cool to the touch.

My only worry with the white roof would be that it may look dirty faster. My black car on the other hand looks dirty half a day after a full wash, while a white or even better - a silver one - looks cleaner than that after a month without washing it. 

 

[PRR]

> check they don't  .... set the gutters too low....

Florida boy.

In Maine, if the ice-pack can't slide free without catching the gutter, your gutters are lost the first spring.

> You also need to have enough insulation in your attic

That's what I was thinking. If he can tell roof-color from inside, he does not have enough insulation. 16" is a good start. He may have the 1949 Economy! 2" stuff I ripped out of a house recently.

 

[JohnRoberts]

Looks pretty cool.  8)

I live under a roof that was insulated to German 2016 standards, so there's half a meter or so of insulating material between the roof and the ceiling (same goes for walls). It's black, but the heat seems to come in only through the windows, walls and ceiling are cool to the touch.

My only worry with the white roof would be that it may look dirty faster. My black car on the other hand looks dirty half a day after a full wash, while a white or even better - a silver one - looks cleaner than that after a month without washing it. 

I have spent the last couple months researching roofs around town (during my bike rides), and around the internets. There are a few typical causes of roof stain/discoloration. The major one is leaves from overhanging tree limbs. I cut down a major (8") branch from a nearby pecan tree to create clear air space above my entire roof (In theory this increases heating from sunlight).

In my pursuit of cheap, I investigated white shingles, that seems like a win-win, cheap and light colored, but apparently the white shingles are notorious for getting infested with some airborne mold/biotics that turns them black quickly. Apparently they make a version of white shingle with copper embedded to control the discoloration, but it all sounds a little dodgy.

I also looked at the several dark colored coated tin roofs around town and they all look like they pick up typical stains from leaves.  There are also several bare tin (galvalume) roofs and they look unacceptably variable. One older bare roof building aged evenly and looks OK (aluminum oxidizes and forms protective outer layer), but one new house, not even occupied yet, looks like crap IMO (multiple different shades of roof, perhaps from different batches). 

We'll see what happens, I am optimistic my roof has a fair shot of looking good, longer than I will care about it.  :-\

wrt attic insulation, my house has average to above average for MS, but this isn't Maine so the house doesn't even have storm windows and other features typical in colder climates.  I made my own double insulated windows mounted on the inside.  This makes a huge difference to heating /cooling load. I did this several years ago to make house warmer in winter, but effect on cooling was significant. I have a second air conditioner in my bedroom that I haven't even turned on for a few years.

I am cooling my entire house with one through-wall unit, about the size of a large window unit in my living room. The most noticeable improvement is not just slightly cooler temps, but the entire house is cooler, not just the room with the air conditioner blowing cold air.  I do not want to make more of this than it is. It makes a noticeable difference in the margin as I expected. Come winter I may miss the extra heat.  :

It was raining this morning and I didn't even notice the rain until I looked out the window and saw the rainwater streaming off the roof.  More attic insulation over the bedrooms than the main living room so I can hear heavy rain out there in the main room (as a low rumble), but not noticeably louder than before .

[edit] it is quieter! I just put on my shoes to walk across the street to get my newspaper from the post office and couldn't because it is still raining.    I didn't notice the rain still coming down. [/edit]

JR

 

[AnalogPackrat]

Please help me select a color for this roof…it’s gonna be an architectural shingle … I’m not set on a brand yet but leaning toward atlas. I never minded the original color but if there is something they will make it look better and gave better curb appeal I’d like to do that! I’m thinking pewter or black, but I had a designer saying 100% weathered wood what are y’all thoughts?

A gray tone that picks up the colors on the granite wall would look good. What you've got isn't bad, IMO. Maybe a product that had random variation in it would work (kind of like a real slate roof looks). I would avoid darker gray or black due to increased heating in summer.

If "weathered wood" means silvery gray driftwood, that would work. If it means anything brown, I think that wouldn't work well with that nice stone section on the front of the house.

 

[JohnRoberts]

A gray tone that picks up the colors on the granite wall would look good. What you've got isn't bad, IMO. Maybe a product that had random variation in it would work (kind of like a real slate roof looks). I would avoid darker gray or black due to increased heating in summer.

If "weathered wood" means silvery gray driftwood, that would work. If it means anything brown, I think that wouldn't work well with that nice stone section on the front of the house.

I put a light colored roof on my house to reduce summer cooling costs and maybe it works, but a review of my annual energy use suggests I use more energy during cold winter months so maybe a dark roof would make more sense financially.

YMMV so try to review your personal situation.

JR

 

[scott2000]

Please help me select a color for this roof

They have paint selector programs so I decided to look real quick...Maybe there's something similar for roofs
https://www.iko.com/na/learning-center/design-center/roof-color-selector/