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philuk

vent.jpg

 

I'm looking to install a couple of these to vent the roof, when i get round to building, wind powered, turbo extactors,

 

Maybe fit one to vent the roof space and make a piped central extractor to vent bedrooms with a vent in each ceiling

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But I am 100% sure it is still cooler than a dark colored truck! 

Exhaust fans are great, but color makes a HUGE difference--White repels and dark attracts. Touch a dark colored car in the sun and touch a white one. My builder has been in the business for many year

Well as somebody from Florida I know VEry well that light colored or white roofs make the house exponetially cooler. Of course it is also a scientific fact that white repels heat while dark attractsab

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Knowdafish

I have a white truck. It is hotter than Hell if it has been left out in the sun. Oh...and you can burn yourself on that cool surface.

But I am 100% sure it is still cooler than a dark colored truck! 

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thebob

As long as you use the foil covered insulation under the steel sheeting, and vent the roof properly, it really doesn't make that much difference what the roof color is. I will have an exhaust fan in the roof (near the peak on the back side) to pull hot air out of the attic area if it builds up.

 

Light colored roofs are also a maintenance point. The darker roof is hotter and expands more so so the welds fracture faster because of the constant contraction/expansion cycle.

 

When you insulate the roof, don't insulate about 12" each side of the ridge, to allow heat out of the roofspace!

 

Shingles are just a poor mans way to have a roof that looks like slate or tile. The look really "pre-fab" to most euros.

 

@ Cebubird, I second Boysen Laguna White roofguard, and make sure you use the correct primer as well.

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Dragon

I will pass along the things I was told by my contractor.

The taller the roof the better and with many vents.

People like red roofs because it will not show rust spots later.

Only foreigners ask for insulation.  Filipinos consider that a waste of money.

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David_LivinginTalisay

Personally, if I was have another house built in the Philippines, I would go for a BIPV Roof.

BIPV - Building Integrated Photo Voltaic

 

Instead of bolting PV Solar Panels to an existing Roof (that might need strengthening, to take the extra weight). why not employ a roofing structure that is designed for PV use?

 

There are several types but basically for normal roof (as opposed to Terrace and Car Port shades), it can be BIPV Standing seam, or BIPV 'Tiles'.

englert-sunnet-solar-standing-seam-roof-

 

BIPV_module_solar_roof_tile_55W.jpg

 

bipv1.jpg

 

POWERHOUSE-Solar-Shingle_12.091.jpg

PV 'Shingles'?

 

492118570_253.jpg

 

1263861226170_hz_myalibaba_web11_15867.j

 

Whilst looking for images of such BIPV Roofing, found this one that give Solar Electric and Solar Hot Water:-

 

 

Snack on the Sun with a Solar Sandwich

By archives on Sep. 8, 2011    | Topics: Solar    Comments (10)

Solar-Sandwich-by-Englert-568x375.jpg

New Jersey-based Englert, a company that specializes in metal roofing and gutter systems, recently earned a citation from Architect Magazine for their incredible Solar Sandwichroof system.  On the surface, it looks like any other standing-seam metal roof with columns of thin-film photovoltaic solar.  Yet below that, to capture the warmth generated from hot metal roofing, there’s a grid of pex-filled purlins with a water and glycol solution for a solar thermal system.

Solar-Sandwich-w-Glycol-568x375.jpg

The system connects with conventional heat transfer and distribution systems for residential and commercial hot water systems, radiant floor heating systems, and swimming pool heaters, according to Englert.

Dawn Solar Systems makes the solar thermal component, while the thin-film PV aspect is similar to what’s provided in the EnergyPeak system with Uni-Solar PV laminates.  In this case, it’s the SunNet BIPV system, which uses an Englert metal roof.

Solar-Sandwich-Roof-Installation-568x334

[+] Learn more about the Solar Sandwich from Englert.

http://www.englertinc.com/solar-energy-systems/solar-thermal-energy-systems.html

 

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Dolsos

 

Personally, if I was have another house built in the Philippines, I would go for a BIPV Roof. BIPV - Building Integrated Photo Voltaic

 

Thats great info David, have you seen those available here or would you have to import it yourself?

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David_LivinginTalisay

Thats great info David, have you seen those available here or would you have to import it yourself?

 

The BIPV 'Tiles' are made in China.

 

Most of the thin Film PV self adhesive rolls for the standing seam steel roofing, seems to be outside of China or produced there under license so cost has not fallen so much.

 

I would use the glass PV Panels that go into Aluminium Framing to create a terrace awning, window awnings, or car port roof.  This gives shade, protects from rain, and generates electricity.

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Knowdafish

I believe the key to house cooling is in insulation and setting up adequate convection currents in the attic. If you can set up air flow where cool air is being pulled in through vents in the eaves, and heated air is escaping through vents high in the roof, then the attic area will remain close to the outside temperature. I will add a fan to that passive system to help if the self ventilation falls behind, but that shouldn't be very often. Now, it is possible to coat your roof with coatings than will prevent adsorption of heat, or you can simply insulate against that heat. I don't particularly care for the look of a white roof. It reminds me of the crap they put on mobile homes to reseal the roofs. So...for me it is partially an aesthetic question.

 

http://www.mrinspector.net/mutual-resources-psds/Attic_ventilation.pdf

 

attachicon.gifRoof Venilation.jpg

 

http://www.nrca.net/consumer/attic_ventilation/passive.aspx

 

I also believe that it is extremely important that you adequately insulate the area just above your top floor (living space). If I ever decide to build in living space into my attic, then I will put insulation in the roof trusses, but for now, my main insulation layer will be below the attic (and above my second floor). I will also have the roll-type foil-backed foam insulation just under the roof sheeting

 

Therefore, I believe that if you set up adequate convection currents in conjunction with proper insulation, you really don't need to worry too much about roof color. You can choose the roof color that looks good to you.

 

Ridge venting works out very well, But it really needs to be well designed in order for it to be problem free. The problem is when the rain is blowing sideways, such as what happens during strong winds or a typhoon. In a situation such as this a "normal" ridge vent will leak massive amounts of water into the attic.

 

vent.jpg

 

I'm looking to install a couple of these to vent the roof, when i get round to building, wind powered, turbo extactors,

 

Maybe fit one to vent the roof space and make a piped central extractor to vent bedrooms with a vent in each ceiling

 

These have a tendency to leak also during periods of heavy rain.

 

 

Personally, if I was have another house built in the Philippines, I would go for a BIPV Roof.

 

BIPV - Building Integrated Photo Voltaic

 

Instead of bolting PV Solar Panels to an existing Roof (that might need strengthening, to take the extra weight). why not employ a roofing structure that is designed for PV use?

 

There are several types but basically for normal roof (as opposed to Terrace and Car Port shades), it can be BIPV Standing seam, or BIPV 'Tiles'.

 

englert-sunnet-solar-standing-seam-roof-

 

BIPV_module_solar_roof_tile_55W.jpg

 

bipv1.jpg

 

POWERHOUSE-Solar-Shingle_12.091.jpg

PV 'Shingles'?

 

 

492118570_253.jpg

 

1263861226170_hz_myalibaba_web11_15867.j

 

Whilst looking for images of such BIPV Roofing, found this one that give Solar Electric and Solar Hot Water:-

 

 

Snack on the Sun with a Solar Sandwich

By archives on Sep. 8, 2011    | Topics: Solar    Comments (10)

Solar-Sandwich-by-Englert-568x375.jpg

New Jersey-based Englert, a company that specializes in metal roofing and gutter systems, recently earned a citation from Architect Magazine for their incredible Solar Sandwichroof system.  On the surface, it looks like any other standing-seam metal roof with columns of thin-film photovoltaic solar.  Yet below that, to capture the warmth generated from hot metal roofing, there’s a grid of pex-filled purlins with a water and glycol solution for a solar thermal system.

Solar-Sandwich-w-Glycol-568x375.jpg

The system connects with conventional heat transfer and distribution systems for residential and commercial hot water systems, radiant floor heating systems, and swimming pool heaters, according to Englert.

Dawn Solar Systems makes the solar thermal component, while the thin-film PV aspect is similar to what’s provided in the EnergyPeak system with Uni-Solar PV laminates.  In this case, it’s the SunNet BIPV system, which uses an Englert metal roof.

Solar-Sandwich-Roof-Installation-568x334

[+] Learn more about the Solar Sandwich from Englert.

http://www.englertinc.com/solar-energy-systems/solar-thermal-energy-systems.html

 

 

These systems are a very good idea, but proper insulation is a must! The water heater coils trap massive amounts of heat, and solar panels do too. In fact, if solar panels aren't kept from getting too hot they lose a lot of their efficiency. Most solar panels are designed to be installed raised up slightly off of a roof for cooling purposes. I'm not sure how solar shingles would stay cool. 

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Dolsos

 

I'm not sure how solar shingles would stay cool. 

 

Maybe a well ventilated attic under the panels would draw enough heat away and out to keep them working.  Or maybe they just add in extra panels to account for the efficiency loss?

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cebubird

Light colored roofs are also a maintenance point. The darker roof is hotter and expands more so so the welds fracture faster because of the constant contraction/expansion cycle.

 

When you insulate the roof, don't insulate about 12" each side of the ridge, to allow heat out of the roofspace!

 

Shingles are just a poor mans way to have a roof that looks like slate or tile. The look really "pre-fab" to most euros.

 

@ Cebubird, I second Boysen Laguna White roofguard, and make sure you use the correct primer as well.

 

Well as somebody from Florida I know VEry well that light colored or white roofs make the house exponetially cooler. Of course it is also a scientific fact that white repels heat while dark attractsabsorbs heat. The "crap" that headshot refers to is called Kool shield and it is terrific.I learned of the Boysen Roofguard from somebody here on the forum.

Our home is almost finished and again, the contracters were inside for 2 hours this hot afternoon, and were again marveling at how comfortable inside. The workers, some of who have been doing this for many years, comment everyday at how cool it it is.

I certainly am not going to criticize anyone who wants a dark colored car or roof here as that is their business, but facts are facts and light is cooler. PERIOD.  

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Headshot

Well as somebody from Florida I know VEry well that light colored or white roofs make the house exponetially cooler. Of course it is also a scientific fact that white repels heat while dark attractsabsorbs heat. The "crap" that headshot refers to is called Kool shield and it is terrific.I learned of the Boysen Roofguard from somebody here on the forum.

Our home is almost finished and again, the contracters were inside for 2 hours this hot afternoon, and were again marveling at how comfortable inside. The workers, some of who have been doing this for many years, comment everyday at how cool it it is.

I certainly am not going to criticize anyone who wants a dark colored car or roof here as that is their business, but facts are facts and light is cooler. PERIOD.  

 

You are absolutely correct that the lighter the surface, the better it will be at reflecting sunlight. And...if your attic is going to be living space, that should probably be considered. Insulation should also be considered, even though it was mentioned earlier that Filipinos don't understand why you need insulation. If it isn't properly insulated, even a white roof will absorb heat from the sun, and after a while, the space directly under the roof will not be a nice place to be. My attic will not be used for anything but utilities, so I'm not too concerned. And like I said, there will be adequate insulation between the attic and my second floor living space. For that reason, for me, roof color is an aesthetic issue...not a heat issue. With proper ventilation built into the eaves and peak of my roof, my attic shouldn't heat up too much even with the grey color roofing that I'm using.

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Knowdafish

The BIPV 'Tiles' are made in China.

 

Most of the thin Film PV self adhesive rolls for the standing seam steel roofing, seems to be outside of China or produced there under license so cost has not fallen so much.

 

I would use the glass PV Panels that go into Aluminium Framing to create a terrace awning, window awnings, or car port roof.  This gives shade, protects from rain, and generates electricity.

They are also made in the U.S.

 

http://www.dowpowerhouse.com/why-solar/index.htm

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David_LivinginTalisay

.

These systems are a very good idea, but proper insulation is a must! The water heater coils trap massive amounts of heat, and solar panels do too. In fact, if solar panels aren't kept from getting too hot they lose a lot of their efficiency. Most solar panels are designed to be installed raised up slightly off of a roof for cooling purposes. I'm not sure how solar shingles would stay cool. 

 

That is correct PV cells work more efficiently if they are kept cool.

 

Do a search on YouTube and you might find a Video where a guy puts a PC panel in a fish tank, and it shows the Volts /Amps to a load, increases as it got cooler.

 

I was contemplating if one could combine water-cooling with PV panels to i) cool the PV panel, ii) generate hot water (or pre-warm the feed to a solar powered water heater (evacuated tube),  My idea was to consider the raised seam type BIPV, and on top of the thin film stick on PV strip, add a layer of that Polycarbonate-Hollow-Sheet (that is a series of box sections),  Have these filled with water and the water would conduct away some of the heat and thermal Conduction, wold take the heated water up the slope to the ridge, where it could be taken to a a storage tank (or feed into a solar water heater to increase the temperature if required),  Fresh cold water at the bottom, would replace the water drawn off the top.

 

post-198-0-05051400-1369066651_thumb.jpg

 

Now I see this  englertinc.com, has done just that, but more along the lines of a water cooled heat sink.

 

post-198-0-69103900-1369066655_thumb.jpg

 

 

The bottom layer:

A Englert Thermal Energy System installed under the standing seam metal roof provides energy for heat and hot water. The Thermal Energy System also automatically cools the metal roof making the BIPV more effective. Together they lower energy costs, reduce dependency on conventional energy sources, and reduce pollution

 

http://www.englertinc.com/html5/ogp/solar_sandwich.ogg

 

 

Edited by David_LivinginTalisay
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thebob

The roof angle is important because of the angle of the sun. Flat roofs are perpendicular to the sun at noon when it is hottest. That is one reason why high roofs are cooler, because they have a shallower angle to the sun for most of the day and are only perpendicular in the early morning and late evening.

 

Alignment is also important. An East/West facing roof will be hotter than a NE/SW facing roof as the angle to the sun will be better in the morning/evening.

 

Metal roofs heat up and then radiate heat in the infrared. Metal and air are almost transparent to this radiation, so the heat shines straight through. Reflective foil helps to stop it but not completely. A hot roof space is usually hot because of the steel holding heat, not the air. That is why roof fans don't work as well as expected. Flowing air doesn't remove the heat from the structure, that shouldn't have been there in the first place.

 

The hotter that the metal gets, the more heat is radiated in the infrared spectrum. Specialized roof paints, like the Boysen Laguna White roofguard, which is grey by the way, are designed to combat this problem. 

 

Treating roof welds against rust is another subject, but "tinning" them with a blow lamp and a copper with plumbers lead is far more effective than any primer or paint.

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easy44

The roof angle is important because of the angle of the sun. Flat roofs are perpendicular to the sun at noon when it is hottest. That is one reason why high roofs are cooler, because they have a shallower angle to the sun for most of the day and are only perpendicular in the early morning and late evening.

 

Alignment is also important. An East/West facing roof will be hotter than a NE/SW facing roof as the angle to the sun will be better in the morning/evening.

 

Metal roofs heat up and then radiate heat in the infrared. Metal and air are almost transparent to this radiation, so the heat shines straight through. Reflective foil helps to stop it but not completely. A hot roof space is usually hot because of the steel holding heat, not the air. That is why roof fans don't work as well as expected. Flowing air doesn't remove the heat from the structure, that shouldn't have been there in the first place.

 

The hotter that the metal gets, the more heat is radiated in the infrared spectrum. Specialized roof paints, like the Boysen Laguna White roofguard, which is grey by the way, are designed to combat this problem. 

 

Treating roof welds against rust is another subject, but "tinning" them with a blow lamp and a copper with plumbers lead is far more effective than any primer or paint.

The Laguna White on my roof looks white to me.

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