Roof Insulation

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Roof Insulation

Postby patsfangr » Fri Sep 16, 2005 10:07 pm

I'm planning on having insulation put into my roof. I recently received a recommendation for an Australian based company named "Cool and Cosy". Is anybody here familiar with that company? If so, what is your opinion?

What other companies would any of you recommend for this work. Obviously, the highest priority for us is effective insulation. Cost, while important, is only second in my prioritization to that objective.

I am also considering adding some sort of extraction fan system. Your thoughts and recommendations on providers for that would also be appreciated.

Thanks in advance for the advice!
George
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Postby Screws » Thu Sep 22, 2005 11:25 pm

Is that So Cal as in Southern California?
Are you insulating against solar heat (as in Thailand) or against both heat and cold?
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Postby patsfangr » Thu Sep 22, 2005 11:34 pm

OOPS! Sorry about the confusion. I NOW live in Southern California. I have bought a house in Pattaya, and will be moving there early next year. It's that house in Pattaya that I want to insulate. - George
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Postby Itchy » Fri Sep 23, 2005 7:23 pm

Effective roof insulation is essential, I have a friend who measured the temperature under his roof at 55DegC, that?s like having a huge toaster beaming heat through your ceilings into your rooms.

He solved the problem by adding about six inches of glass fiber insulation (comes in pre formed plastic covered pads and by adding two ventilation windows, one in each of the eaves.
I have been in houses where a fan has been installed but has resulted in vibration noise (they also use electricity), far better to rely on natural convection.

The guy I know that took these steps told me that after insulating and ventilating the roof space he halved his use of A/C.


Things to take into account:

Position the windows as high in the eaves as possible, to reach and allow the flow of the hottest air.

Make the ventilation windows as large as practically possible, my mate used standard single window frames with wooden louvers over the opening.

Don?t forget to add insect screens AND security bars inside the frames. You have to be very careful to keep the cockroaches out ? and the insects!

Finally, I know Thais sometimes use rice husks for insulation but I wouldn?t advice this for a number of reasons. If they become damp, they will rot, they might be providing food for pests and perhaps worst of all they are flammable. Given that most people are running electrics through their roof space, I?d not want to take the risk.
Last edited by Itchy on Fri Sep 23, 2005 7:33 pm, edited 2 times in total.
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Postby Itchy » Fri Sep 23, 2005 7:30 pm

Here's a sketch
Attachments
roof ins.pdf
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two types of insulation

Postby dozer » Fri Sep 23, 2005 8:30 pm

I notice there are two types of insulation used here, the type being described which would sit on top of the ceiling and the more commonly used insulation sheets which are installed directly under the roof tiles.
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Postby Itchy » Fri Sep 23, 2005 8:40 pm

I think the difficulty with under the roof tile insulation is getting it to be thick enough to be effective.

Glass fibre insulation is very cheap, light weight, very easy to install so you can keep piling it in until you get sufficient thickness to achieve the desired insulation.

It's also easily removed if you ever have to do maintenance.

I've also seen spray on insulation, often advertised as an added security function (Thai burglars often come throught the roof), but this spray on stuff is horendously expensive, and again not really thick enough to provide very effective insulation.

Of course the disadvantage of roof space glass fibre is you can't use the space for storage.
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under roof insulation

Postby dozer » Fri Sep 23, 2005 9:20 pm

Yes, the under roof insulation is fairly thin. Insulation is probably the wrong term as it is designed to keep heat out as opposed to keeping the cool air in. I saw a little demo at Homepro which I thought was somewhat impressive. The have a heat lamp (emulating the sun) above a section of the roof insulation in an enclosed area. The heat differential above and below the insulation is large (hot above the insulation layer, cool below).

This stuff is used in almost all of the new developments going up, although that doesn't mean it is good.
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Postby Itchy » Fri Sep 23, 2005 9:44 pm

Insulating to keep heat out is the same principle as insulating to keep heat in.

I'd be interested to see a measurement done on the temperature in the roof space with this thinner material, depending on the colour of the roof tiles the external temperature can be extremely high, and it only takes a very little heat to get through the insulation before the heat starts loading your A/C usage.

Keeping in mind the huge area of a roof, the heat gain from a even a slightly less effective insulation can be very significant
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Postby cruzing » Fri Sep 23, 2005 11:49 pm

Itchy wrote:Finally, I know Thais sometimes use rice husks for insulation but I wouldn?t advice this for a number of reasons. If they become damp, they will rot, they might be providing food for pests and perhaps worst of all they are flammable. Given that most people are running electrics through their roof space, I?d not want to take the risk.


Are you talking about regular rice husks. We used Burnt rice husks. Can't see that they'd be flammable or a very inticing meal for bugs either.

Might add that was only in the double walls. Ceiling has fibreglass.
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insulatio

Postby dozer » Sat Sep 24, 2005 8:32 am

I'd be interested to see a measurement done on the temperature in the roof space with this thinner material, depending on the colour of the roof tiles the external temperature can be extremely high, and it only takes a very little heat to get through the insulation before the heat starts loading your A/C usage.

Indeed. The thing to do would be to compare two identical units, on with this reflective insulation and one without. If the Homepro demo accurately portrays the situation, I would expect the temperature near the roof of the house without to be higher.

In any event, this insulation isn't expensive and it can be used in conjunction with the insulated blankets laid on top of the ceiling. Those are especially productive for A/C areas.
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Postby Screws » Thu Oct 06, 2005 10:31 pm

Bulk or (non) conductive insulation is of little use in hot climates. However I have had a lot of success with reflective insulation in Australia and Thailand.
I was a teacher in a private school in north Queensland some years ago. One of the classrooms simply had a galvanised iron roof. Another teacher and I put in a double layer of double sided sisalation and a ceiling. It changed the room from a black hole of Calcutta to the coolest room in the school.

Last year I moved into a house belonging to a friend, near Pattaya. This house was also hell, from 10 or 11 am on sunny days, the heat was unbearable. All you could think of was to escape outside to under the mango tree. So I got my friend to do the same; put in two layers of double sided Sisalation. House is great now; we put in air conditioning at the same time - I have never turned it on. Instead of escaping the heat outside now, if you are outside, even under the mango tree, you escape the heat by going inside. The ceiling temperature before was typically ambient plus 10 deg. C; now it is ambient plus around 2 degrees.

I know that a light coloured roof is a good idea, having painted our roof white in the 60's, but there is also no substitute for a good reflective barrier. I would suggest that you test this by putting a couple of layers of this material on the roof in the morning, then check the temperature underneath a few hours later. I could not consider having a house without it, as it has been so effective. And so cheap, esp if done in the building, not later.

I have heard that the Australian government has made it illegal to build a house without it.

Unfortunately I have now moved into a concrete roofed building, so i have a new set of challenges.
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Postby tutsi » Tue Oct 25, 2005 2:07 pm

anyone have contact details for a fibreglass roof insulation supplier/installer? I live in Suphanburi and I know that I may have to hire someone out of either BKK or Pattaya for this work.

Please PM.
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Postby teletiger » Sat Oct 29, 2005 9:07 pm

what do you do if you have no eaves?
regards
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Postby cruzing » Sat Oct 29, 2005 9:51 pm

oops!
Last edited by cruzing on Sat Oct 29, 2005 9:59 pm, edited 2 times in total.
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