Need Help Cooling My House/Attic in Bangkok

[chiang mai]

Some may find this useful:

"Touch your ceiling on a warm, sunny day. A hot ceiling tells you that the attic is acting like a solar oven".

http://www.familyhandyman.com/attic/how-to-improve-attic-ventilation/view-all

"How many vents do you need? First determine your attic area by multiplying the length by the width. A 30 x 40-ft. attic, for example, has an area of 1,200 sq. ft. Then aim for about 1 sq. ft. (144 sq. in.) of vent opening per 150 sq. ft. of attic".

What that says is that an attic/upper floor roof area of 1,600 square feet (circa 150 square metres) needs a decent area of the roof dedicated to ventilation.

The link does not discuss Thailand directly but the information is directly applicable to all countries.

Edited May 2, 2015 by chiang mai

[Naam]

Actually I now have a related question that pertains to attic insulation:

It's been agreed that foil backed insulation needs to be installed with the foil side facing the heat source, in Thailand that means installing it with the foil facing the roof, this to prevent condensation and to reflect the heat back towards the roof.

But most attic insulation in Thailand seems to be encased entirely in foil. Whilst that allows for heat to be reflected back towards the tiles it must surely mean that there is a potential for condensation build up on the underside, or have I missed something?

zero condensation if attic is properly ventilated.

[jsgatse]

OK, so the votes (as I calculate/decipher) were

2 for Whirlybird

and

2 for attic floor insulation

The attic floor insulation is easy - they sell it and install it down the street at the local HomePro. Any history with a good brand/R level that you can recommend?

For the whirlybird - they sell them at these little mom and pop hardware stores around my house. But, they look super cheap and as if they would stop spinning well and start squeeking up a storm rather soon. Is there anyone in Thailand who sells/imports/installs proper whirlybirds that anyone out there knows of?

Thanks to all.

[Naam]

OK, so the votes (as I calculate/decipher) were

2 for Whirlybird

and

2 for attic floor insulation

The attic floor insulation is easy - they sell it and install it down the street at the local HomePro. Any history with a good brand/R level that you can recommend?

For the whirlybird - they sell them at these little mom and pop hardware stores around my house. But, they look super cheap and as if they would stop spinning well and start squeeking up a storm rather soon. Is there anyone in Thailand who sells/imports/installs proper whirlybirds that anyone out there knows of?

Thanks to all.

it's always good to read the comments of eggsburts who can judge the performance of a technical gadget just by looking at it.

seven years ago i built a small home for our staff and had a locally made whirly bird installed. tomorrow i'll have it ripped off because it might soon stop spinning well and squeek during a storm. and now i will google for imported whirly birds

Edited May 6, 2015 by Naam

[weegee]

Read this topic completely...As I have the same problems as others, I will be using those vent tiles from Australia. That, to me seems the best way for a tiled roof.

I will be checking the price tomorrow if anyone is interested...The rest seem to have problems arriving after a couple of years with worn out Whirlies and leaky roofs.....

My ceiling is that hot , even the geckos wont live there...

Thanks for the informative reading fellas

[chiang mai]

Read this topic completely...As I have the same problems as others, I will be using those vent tiles from Australia. That, to me seems the best way for a tiled roof.

I will be checking the price tomorrow if anyone is interested...The rest seem to have problems arriving after a couple of years with worn out Whirlies and leaky roofs.....

My ceiling is that hot , even the geckos wont live there...

Thanks for the informative reading fellas

I'll PM you after getting over my jet lag.

[weegee]

Read this topic completely...As I have the same problems as others, I will be using those vent tiles from Australia. That, to me seems the best way for a tiled roof.

I will be checking the price tomorrow if anyone is interested...The rest seem to have problems arriving after a couple of years with worn out Whirlies and leaky roofs.....

My ceiling is that hot , even the geckos wont live there...

Thanks for the informative reading fellas

I'll PM you after getting over my jet lag.

Im off to the A/C and will log on tomorrow morning...Thanks

[chiang mai]

I'm strongly considering placing insulated foil across the rafters, starting about one foot up from the eves and ending just below the height of the gable vents. The purpose of this is to reflect/deflect/redirect upwards, towards the exit, any heat that is radiated from the roof tiles, this should provide an air gap between the insulated foil and the roof tiles of about 20cms.

As things stand presently I have four gable vents which will soon be doubled in size and also a series of eves/soffit vents measuring about two square feet in total. My attic floor is not insulated (yet) and before doing so, I want to try and understand the usefulness of trying to deflect the heat from the tiles before insulating against the heat they generate.

Has anyone tried the above approach and if so/not, any observations/comments?

[djlissa]

Yup ^^^ let the hot air out.

Do you have gables? Gable vents would look nicer than whirlybirds and be equally effective, and you could add fans later if they weren't enough.

Nope, no gables, as my roof is like a pyramid...the only solution is to let this air out would thru a whirlybird, as I see it.

roof fans are available but bloody expensive. my stupid contractor did not consult me and purchased/installed one for 17,000 Baht (three-phase and overkill wattage). had to spend another 15,000 Baht on a frequency controlling device to reduce RPMs stepless.

lesson learned! a couple of years later i built a small house for our staff, had a whirly bird installed and attached an electric fan to the whirly. total cost if i recall correctly was approximately 5,000 Baht which also included a cheap timer.

roof fans.jpg

[djlissa]

Stupid me rented a house in Chiang Mai without checking for heat build up late in the day and now that I am in, the attic is an oven most of the night.

Does anyone know a decent contractor in CM that can install blown-in attic insulation and maybe a whirly bird vent in the attic. I can't even find access to the attic and can't image how hot it gets late in the day.

thank you any help is appreciated

Denny

[chiang mai]

We've never heard of anyone here offering blown in insulation in all the years we've discussed this subject.

A couple of large places on the Hang Dong road sell whirly bird fans, look for the displays in front of the shops and on the sidewalk. Perhaps stop and ask at one of those shops for the name of an installer.

I have yet to come across a contractor in Thailand who knows much about insulation and all it entails.

EDIT: Homepro sells rolls of R35, foil encased fibreglass/wool, 2.4 square metres of 6 inch costs about THB 325 a roll, when on special.

Edited May 9, 2015 by chiang mai

[djlissa]

Really, no one does this? In the states it is very popular, in fact in Orlando Florida where I lived the electric company even paid about half the cost. it's almost as good as the bat type insulation and is simple to install.

Hmmm maybe a good business opportunity here?

Thank you for replying and I will let everyone know if I do find someone

[Pacificperson]

A picture is worthwhile. I would do both the ventilation and the insulation. You might also consider painting the cement tiles with a reflective roof paint if you are willing to deal the the upkeep. You would be surprised at how much heat buildup it prevents.

Edited May 9, 2015 by Pacificperson

[Pacificperson]

I am back to ask a question. Why are the majority of roofs in Thailand dark colored? (You can use Google Earth to verify this.) I have lived in the tropics for more than 25 years and the effectiveness of white, reflective painted roofs is clear to me. You can almost walk barefoot on a well maintained coated roof on a sunny afternoon. Isn't an ounce of prevention worth a pound of cure?

Edited May 9, 2015 by Pacificperson

[Naam]

Stupid me rented a house in Chiang Mai without checking for heat build up late in the day and now that I am in, the attic is an oven most of the night.

Does anyone know a decent contractor in CM that can install blown-in attic insulation and maybe a whirly bird vent in the attic. I can't even find access to the attic and can't image how hot it gets late in the day.

thank you any help is appreciated

Denny

easy to install blown-in insulation beats hands down any other in Thailand available insulation (except the PU foam which in comparison is extremely expensive). that applies especially in single story homes where the gypsum ceilings are suspended by straps.

unfortunately in Thailand "no habb"

p.s. in my view it would be worthwhile to enquire whether any other medium (not necessarily blown-in) is available to use as insulation. for example in Europe small styrofoam pieces are available to use in the cavity of double walls. even a manual application would be quite cheap.

[ben2talk]

All the above is good stuff - maybe. The only way to cool a house in this weather is A/C. Duh.

Do an experiment, build a small greenhouse and sit inside. Then fit aircon and turn it on. See if you get cool before the aircon expires.

My first plan is to build an extension (Kitchen) at the rear (sunny side) of our house, with double height (simple/cheap silver backed metal roofing sheets) steel structure. This will provide shade for the entire rear wall of the house...

Next up is to seal in the airconditioning on the upstairs with foil covered fibreglass rolls.

I'm curios if there would be a huge difference between 3 inch and 6 inch (6 inch would be tougher to install in some parts, and I think one of the largest benefits is the reduction of roof radiation hitting the thin ceiling...

Thirdly, a prayer that the adjacent houses will help by cooling the largest walls from their side...

IF I can make it half as good as my condo was, I'll be happy. The condo was 40m and I could leave the 18000 btu inverter running (variable power - minimum around 4000 btu before the compressor turns off) and find that it rarely had to work more than 20 minutes before it started scaling down. Total monthly bill 1400 (compared to the older Samsung 12,000 btu unit at 2200 per month).

We started out with Mitsubishi inverter units - and now need to work fast to reduce their consumption. The extension (costing about 50,000 total) will add a 3.5 by 5.5 metre kitchen, plus a 2nd floor patio with access via roof door and stairs from the kitchen/laundry room.

It's a 'townhouse' (terrace) so roof modifications are not straightforward; but I'm sure that a decent ceiling insulation will make actual attic temperatures (as well as the radiant heat coming from the roof) will prove irrelevant.

I'm slightly curious to know whether the foil-topped insulation will collect dust, so I guess I'll have to go up and check periodically - maybe take a vacuum cleaner to clean up periodically.

Now, about prices... Currently you can get

SUNSHIELD 3" 0.6X4M EX-COOL FIBGLASS INSULATION THB 239

(Stay Cool - the green packs) CHANG 0.6X4M PREMIUM FIBER GLASS INSULATION 325 THB

CHANG 0.6X4M PREMIUM FIBER GLASS INSULATION 150mm (6") 428 THB

SUNSHIELD 0.6X4M EX-COOL FIBER GLASS INSULATION (6") 319 THB

Can anyone dissuade me from going for the cheaper Sunshield product?

Edited April 13, 2016 by ben2talk

[chiang mai]

A partial answer:

Radiated heat from roof tiles that radiates onto the ceiling of the living space needs to be interrupted with a layer of aluminium foil sheeting or radiant barrier, that changes the source of heat from radiated to convected. Three inch insulation will help prevent convected heat (hot air) from reaching the living space but will be defeated quite quickly, a six inch barrier will take longer to defeat - FWIW I have installed 12 inches of aluminium encased wool type insulation on my ceiling/attic floor in addition to the radiant barrier and it withstands even the temperatures we're experiences currently.

Attic ventilation is however the key, post 103 shows diagrammatically what is required, do that and you'll need far less insulation. A note on ventilation: the hot air exhaust points must equal the same surface area as the cool air intake points, put another way, the vents in the eves/sofffits must equal the vent size in the ridge or gable vents, having one square foot of gable venting and five square feet of soffit venting means you have one square foot of roof venting.

EDIT TO ADD: foil encased insulation will collect dust over time but less so if you have adequate attic ventilation because you will have air flow. In my roof space right now there's about one foot of cool air that sits just above the foil encased insulation, this the result of ventilation, that means the insulation hasn't even started to be challenged yet - I have seven square feet of hot air out via vented gables and seven square feet of cool air in via vented soffits. BTW, it's 80 degrees outside right now and in my living room it's 28 degrees and the air con hasn't been turned on today. Before I did the works described above the temperature inside would have been the same as or higher than the external temperature, unbearable.

Edited April 13, 2016 by chiang mai

[chiang mai]

A partial answer:

Radiated heat from roof tiles that radiates onto the ceiling of the living space needs to be interrupted with a layer of aluminium foil sheeting or radiant barrier, that changes the source of heat from radiated to convected. Three inch insulation will help prevent convected heat (hot air) from reaching the living space but will be defeated quite quickly, a six inch barrier will take longer to defeat - FWIW I have installed 12 inches of aluminium encased wool type insulation on my ceiling/attic floor in addition to the radiant barrier and it withstands even the temperatures we're experiences currently.

Attic ventilation is however the key, post 103 shows diagrammatically what is required, do that and you'll need far less insulation. A note on ventilation: the hot air exhaust points must equal the same surface area as the cool air intake points, put another way, the vents in the eves/sofffits must equal the vent size in the ridge or gable vents, having one square foot of gable venting and five square feet of soffit venting means you have one square foot of roof venting.

EDIT TO ADD: foil encased insulation will collect dust over time but less so if you have adequate attic ventilation because you will have air flow. In my roof space right now there's about one foot of cool air that sits just above the foil encased insulation, this the result of ventilation, that means the insulation hasn't even started to be challenged yet - I have seven square feet of hot air out via vented gables and seven square feet of cool air in via vented soffits. BTW, it's 80 degrees outside right now and in my living room it's 28 degrees and the air con hasn't been turned on today. Before I did the works described above the temperature inside would have been the same as or higher than the external temperature, unbearable.

EDIT above: should read 38 degrees outside and 28 degrees inside.