metal roofing and reflective foil

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Re: metal roofing and reflective foil

Postby Ians » Fri Jun 23, 2017 9:06 pm

Certainly overkill but more than effective, I assume flat roof.
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Re: metal roofing and reflective foil

Postby Andyfteeze » Mon Jun 26, 2017 1:14 pm

For a tin roof, your best insulation trick is the foil encapsulated fiberglass batts that sell everywhere. But I caution, dont install down lights. They require holes in the insulation for ventilation. Place the insulation over the ceiling plasterboard, the better the rating, the better the effect.

As for roof ventilation, you need a roof ventilator. In australia we used to call them whirlygigs.
Check this out as a start. https://www.bunnings.com.au/our-range/b ... ation/roof

Equalizing outside temperatures and ceiling cavity can take a good 20degrees out of the equation.

My thoughts on a tin roof? In australia, I wouldnt hesitate. Here I would have kittens. Not only are the tin sheets very very thin, the spacing between battens is a ludicrous 1.2m. I am used to 60cm max spacing, 45cm being the normal. The battens aren't even fastened properly, you cant buy fasteners off the shelf like in australia and so everything is "tac welded".
Not full welds, Tac welds. My wife has various pieces added to her house and what i see makes me giggle, hammer my fist in rage and cautious when using their standard materials. In other words, I have little faith in their standards.
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Re: metal roofing and reflective foil

Postby Sometimewoodworker » Mon Jun 26, 2017 5:51 pm

Andyfteeze wrote:For a tin roof, your best insulation trick is the foil encapsulated fiberglass batts that sell everywhere. But I caution, dont install down lights. They require holes in the insulation for ventilation.


Better to also use the foil just under the roof first. It's cheap easy to fit and makes a difference that well outweighs its cost

For lights that depends on the downlight, with the advent of LED down lights that may not be needed

Place the insulation over the ceiling plasterboard, the better the rating, the better the effect.


Can't hurt.

My thoughts on a tin roof? In australia, I wouldnt hesitate. Here I would have kittens. Not only are the tin sheets very very thin, the spacing between battens is a ludicrous 1.2m. I am used to 60cm max spacing, 45cm being the normal. The battens aren't even fastened properly, you cant buy fasteners off the shelf like in australia and so everything is "tac welded".
Not full welds, Tac welds.

For the metal sheet you can buy thin stuff or the same or better quality than you get in Australia.
For the welding what you say suggests that you haven't had good workers or a good supervisor. Properly welded battens are probably better than ones held on with clips. Clips are used there because they are faster to fit so because labour is much higher they are cost effective.

My wife has various pieces added to her house and what i see makes me giggle, hammer my fist in rage and cautious when using their standard materials. In other words, I have little faith in their standards.

The majority of Thai people will take the simple route and accept what is done for an easy life.
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Re: metal roofing and reflective foil

Postby Roger Ramjet » Mon Jun 26, 2017 7:24 pm

Sometimewoodworker wrote:For the metal sheet you can buy thin stuff or the same or better quality than you get in Australia.
For the welding what you say suggests that you haven't had good workers or a good supervisor. Properly welded battens are probably better than ones held on with clips. Clips are used there because they are faster to fit so because labour is much higher they are cost effective.

Everything here has to be supervised. Properly welded battens? Where? The welding crew I had only did runs because I stood over them and made them do it my way. There is nothing wrong with the clips when using Colorbond roofing. They are used extensively in Darwin and other areas that have strict cyclone building standards. I used them on this roof and even though I've lost fibro sheets caused by storms and air currents, not one Colorbond clip has lifted.
The standards in Australia were set by the civilian people under the supervision of Major General Alan Stretton after cyclone Tracy decimated Darwin and its suburbs. The army was used as a communications tool to the outside world and helped civilian engineers with the planning of the new Darwin. Colorbond made a name for itself after Tracy and supplied many homes with free Colorbond and all was clipped after extensive tests were carried out by the Corps of Engineers.
Most modern day houses in cyclone prone areas use Colorbond and clips, not because it's faster and saves on labour, but because they were designed to withstand cyclones.
I wouldn't use the Thai thin tin sheets (mostly made in China), I can rip them with my hands.
The only tin roof I'd use is Colorbond, which comes in various thicknesses and is guaranteed for 30 years.
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Re: metal roofing and reflective foil

Postby Andyfteeze » Mon Jun 26, 2017 8:42 pm

As I said , a tin roof would give me kittens here. Thai trades? Unless I have worked with one before, I see them all as supect.

plumber i just had running pipes had the IQ of a primate. Why stop at two holes for the pipes when 7 will be just as good, sheesh. I turn my back for literaly 10min and they try it on. Luckily for me, the electrical and plumbing is just about done and they all go. I will have some pleasure finishing ALONE. Pi Bah was exclaimed more than once in the last two days. I have two bathrooms that look like swiss cheese. The concreters and block layers/renderers were top notch trades but even there, not without some angst. If they dont want to do something, its usually the most asinine excuse. But thats your cue to say thankyou and let them go.
"why dont you finish rendering around the bathroom windows? No you put the tiles first then we come back." The wife says ok, limply. WTF just happened? :lol: :lol: :lol:

The builder (me) just collected another job.
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Re: metal roofing and reflective foil

Postby kmanonmaui » Fri Jan 12, 2018 7:25 pm

Hi, know this is an old thread, but I think applicable to my questions.

My first contractor install BlueScope without any form or foil backing over the main house. He had indicated that he would just spray foam later. Now I'm concerned about finding a company that will actually do this. We are also about to order BlueScope for the decks and Carport, so some question(s) about that as well:

1. Can anyone recommend a spray-foam contractor, ideally in the Udon Area?
2. Is there some other material I should consider instead?
3. Aside from the noise factor, any benefit to having BlueScope use the form or reflective backer on the roof sheets over the decks and carport?

Thanks in advance for any guidance you can provide.
-k-
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Re: metal roofing and reflective foil

Postby Sometimewoodworker » Sat Jan 13, 2018 5:04 am

kmanonmaui wrote:Hi, know this is an old thread, but I think applicable to my questions.

My first contractor install BlueScope without any form or foil backing over the main house. He had indicated that he would just spray foam later. Now I'm concerned about finding a company that will actually do this. We are also about to order BlueScope for the decks and Carport, so some question(s) about that as well:

1. Can anyone recommend a spray-foam contractor, ideally in the Udon Area?
2. Is there some other material I should consider instead?
3. Aside from the noise factor, any benefit to having BlueScope use the form or reflective backer on the roof sheets over the decks and carport?

Thanks in advance for any guidance you can provide.
-k-

1) sorry no
2) probably not
3) without insulation it will get uncomfortable under the roofed area. I had a measurable 58 degrees C in the underside of a metal roof. So the minimum would be the silver foil sheet, if you get the single sided type make sure you install it shiny side down.http://www.coolthaihouse.com/forum/viewtopic.php?f=40&t=4476
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Re: metal roofing and reflective foil

Postby kmanonmaui » Sat Jan 13, 2018 3:54 pm

Sometimewoodworker wrote:1) sorry no
2) probably not
3) without insulation it will get uncomfortable under the roofed area. If had a measurable 58 degrees C in the underside of a metal roof. So the minimum would be the silver foil sheet, if you get the single sided type make sure you install it shiny side down.http://www.coolthaihouse.com/forum/viewtopic.php?f=40&t=4476


Thanks...finding out the lay of the course as I run it :D
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Re: metal roofing and reflective foil

Postby kmanonmaui » Sun Jan 14, 2018 7:41 am

Sometimewoodworker wrote:without insulation it will get uncomfortable under the roofed area. I had a measurable 58 degrees C in the underside of a metal roof. So the minimum would be the silver foil sheet, if you get the single sided type make sure you install it shiny side down.http://www.coolthaihouse.com/forum/viewtopic.php?f=40&t=4476


Jerome, that was a pretty dramatic temp. difference you achieved with your foil application. Absent a second quote on spray foam (my first was 650 baht per sq. meter x 230 sq. meters = more than the roof cost) I am looking for something else.

For the attic area, which which has already been sheeted, thinking about applying the foil similar to the method you used. Do you think I need to keep the foil as close to the actual roof panels as possible at all points, or would running it across the rafters, leaving an air gap in-between, be acceptable.

Secondly, I've been reading quite a bit that having a ceiling (attic floor) as airtight as possible can also help considerably. And, the addition of some insulation even more so. Any experience and/or thoughts on this?

Thanks,
-k-
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Re: metal roofing and reflective foil

Postby Sometimewoodworker » Sun Jan 14, 2018 6:51 pm

kmanonmaui wrote:
Sometimewoodworker wrote:without insulation it will get uncomfortable under the roofed area. I had a measurable 58 degrees C in the underside of a metal roof. So the minimum would be the silver foil sheet, if you get the single sided type make sure you install it shiny side down.http://www.coolthaihouse.com/forum/viewtopic.php?f=40&t=4476


Jerome, that was a pretty dramatic temp. difference you achieved with your foil application. Absent a second quote on spray foam (my first was 650 baht per sq. meter x 230 sq. meters = more than the roof cost) I am looking for something else.

That price should have got you 50+ mm depth of foam, we decided on 25mm

For the attic area, which which has already been sheeted, thinking about applying the foil similar to the method you used. Do you think I need to keep the foil as close to the actual roof panels as possible at all points,

No

or would running it across the rafters, leaving an air gap in-between, be acceptable.


No problem, you will need to allow for the hot air to exit the roof space.

Secondly, I've been reading quite a bit that having a ceiling (attic floor) as airtight as possible can also help considerably. And, the addition of some insulation even more so. Any experience and/or thoughts on this?
Thanks,
-k-


When we were putting in our ceilings I got a quote for adding insulation on top of the ceilings and it was a very modest amount so had it added to all of them. I think that it makes a significant difference.
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Re: metal roofing and reflective foil

Postby roy.sokolowski » Thu Feb 08, 2018 7:45 am

Our Bluescope roof has been installed. White color, thickest I could buy in Thailand, with the premium foam and foil radiant barrier installed on the underside from the factory (with two solar powered attic fans rated at 650 cfm mounted just below the roof peak). On a hot day you can touch the underside of the foil insulation and it does not feel warm. I did extensive research on the topic of radiant barrier prior to this build in Thailand and before we replaced our roof on our house in Hawaii. This stuff works, and if properly installed with adequate ventilation of the attic area it can dramatically reduce the amount of time that A/C needs to be running. If your attic is at 70 degrees C that heat will eventually be transferred to your ceiling and then into your home. Radiant barrier can significantly reduce the amount of heat that gets trapped in your attic and this can dramatically reduce the amount of heat that eventually enters the living spaces of your house, and needs to be reduced.

If you are still not a believer in the benefits of radiant barrier send me a PM and you can come visit us in Lahansai, Buriram and see for yourself.
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Re: metal roofing and reflective foil

Postby schuimpge » Fri Feb 09, 2018 8:16 am

roy.sokolowski wrote:Our Bluescope roof has been installed. White color, thickest I could buy in Thailand, with the premium foam and foil radiant barrier installed on the underside from the factory (with two solar powered attic fans rated at 650 cfm mounted just below the roof peak). On a hot day you can touch the underside of the foil insulation and it does not feel warm. I did extensive research on the topic of radiant barrier prior to this build in Thailand and before we replaced our roof on our house in Hawaii. This stuff works, and if properly installed with adequate ventilation of the attic area it can dramatically reduce the amount of time that A/C needs to be running. If your attic is at 70 degrees C that heat will eventually be transferred to your ceiling and then into your home. Radiant barrier can significantly reduce the amount of heat that gets trapped in your attic and this can dramatically reduce the amount of heat that eventually enters the living spaces of your house, and needs to be reduced.

If you are still not a believer in the benefits of radiant barrier send me a PM and you can come visit us in Lahansai, Buriram and see for yourself.


There's no arguing against that Roy.

The only thing that always keeps me wondering is the attic-fans. You sure need ventilation or you'd still get (albeit slower) heat building up in the attic.
But I wonder what's the better solution here?
- Passive ventilation with ventilation openings at the roof peak and vents at the soffits
- Or as you have, active ventilation with fans just below the roof peak

My first thought would be that if you actively ventilate, you're pulling hot air from outside continuously over a colder surface (ceilings), which increases heat-exchange between the cold and hot air.
If you're using passive cooling, then hot air will rise slowly and escape through the roof-vents, but it will happen slower, so heat-exchange would slow down also.

Just wondering if anyone here has a bit more knowledge on that?

Cheers,
Luc
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Re: metal roofing and reflective foil

Postby Sometimewoodworker » Fri Feb 09, 2018 9:27 pm

Radiant barrier can significantly reduce the amount of heat that gets trapped in your attic


Not quite. The Radiant barrier will dramatically reduce the heat radiating into the attic, but it does nothing to reduce heat trapped in the attic, except indirectly.

I suspect that you probably ment to say "Radiant barrier can significantly reduce the amount of heat that gets generated in your attic."
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Re: metal roofing and reflective foil

Postby kmanonmaui » Sat Feb 10, 2018 1:40 pm

For our decks and carport, we have the Bluescope with 50mm foam and a METAL (not aluminum) bottom. My problem is that my first contractor ordered the main roof without anything. So, for the main roof I am considering:
1. spray-foam
2. spray-foam + an aluminum radiant barrier after that
3. just a radiant barrier
4. nothing.

Regardless, I plan on:
1. Insulating the attic floor and;
2. Having vent fans on both ends of the long roof...but one bringing in fresh air and one to push it out. I believe, *but do not know*, that simply pushing air out from both gables will create a bit of a vacuum. No circulation will result in a much hotter attic which I believe will result in a heat transfer to the living area below as well as allowing for moisture buildup in the attic.

This said, I would greatly appreciate any commentary and thoughts on my ideas.

TIA,
-k-
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Re: metal roofing and reflective foil

Postby Sometimewoodworker » Sat Feb 10, 2018 1:58 pm

1) Easy to install, sound reduction, depending on thickness heat reduction from OK to good, about 300 Baht sqm per 25mm thickness
2) Not so easily installed, sound reduction, heat reduction from good to great.
3) not sure about ease of installation, no sound reduction, heat reduction good to great, material cost low.
4) 555555 up to you

My opinion;
Fans, suck out at one end (1 or 2), yes. Blow in, I wouldn't bother, I would just have ventilation at one end.

I don't think that you would have a moisture problem in the attic unless you like to set your AC on freezer mode, and even then the ceiling insulation might prevent that.
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