Roof Ventilation system?

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Roof Ventilation system?

Postby Treysd3 » Thu Jan 13, 2011 12:47 am

Hello All

Question for you all.

We will not have eaves on our house for roof vents so I was wanting to install Roof Ventilators on top of the roof.

Is there a certain amount of ventilators that I should put on top of the roof? And were would be the best place to put on roof?

In LOS do you recommend one roof ventilator over another?

Thank you for your help on this.

see pictures of my roof and how many roof vents do you think i need?

FYI I will have Roof foil under the cpac tiles and insulation above the gypsum ceiling.
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This is my roof.
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roof_vent_spin_thing.jpg
Do they have this style in Thailand?
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Re: Roof Ventilation system?

Postby geordie » Thu Jan 13, 2011 6:23 am

really do not think you can have too mutch venting
placement needs to be as high up the roof as you can normally you can buy vented ridge
however you need to allow air to enter from the bottom to create a natural flow upwards the more airflow the more cooling
my comments may be wrong but never deliberately
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Re: Roof Ventilation system?

Postby Roger Ramjet » Thu Jan 13, 2011 6:28 am

Treysd3,
The answer to your question is yes; the rotating aluminum industrial type vent is the most common vent used in Thailand/Bangkok and is available everywhere, just make sure they seal it properly.
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Re: Roof Ventilation system?

Postby Treysd3 » Thu Jan 13, 2011 6:55 am

geordie wrote:really do not think you can have too mutch venting
placement needs to be as high up the roof as you can normally you can buy vented ridge
however you need to allow air to enter from the bottom to create a natural flow upwards the more airflow the more cooling


Thank you Geordie

what is the best way to have the air to enter from the bottom? Sorry if that sounds like a stupid question but I am not a builder. :) Im sure my builder knows all this..... but you never know. I am in America now and I have to send all this info to my GF to make sure it all gets done. She will be going to GH this morning when she gets up and I want to make sure she buys everything needed.

whats also a vented ridge?

My roof is going to be similar to this roof.
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01 1.jpg
Last edited by Treysd3 on Thu Jan 13, 2011 7:00 am, edited 1 time in total.
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Re: Roof Ventilation system?

Postby Treysd3 » Thu Jan 13, 2011 6:57 am

Roger Ramjet wrote:Treysd3,
The answer to your question is yes; the rotating aluminum industrial type vent is the most common vent used in Thailand/Bangkok and is available everywhere, just make sure they seal it properly.


Thank you Roger. I will make sure she buys 2 of the vents today from GH.

How or what is the best way to get up flow of air from our roof in my picture?

My roof is going to be similar to this roof??
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01 1.jpg
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Re: Roof Ventilation system?

Postby Roger Ramjet » Thu Jan 13, 2011 7:14 am

Treysd3,
If you have insulation above the ceiling it will reflect the heat through the tiles upwards, the rotating vent will move slowly taking out the hot air. If there is a breeze outside it will rotate very quickly, ensuring the hot air is extracted at an even greater rate.
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Re: Roof Ventilation system?

Postby Treysd3 » Thu Jan 13, 2011 7:31 am

Roger Ramjet wrote:Treysd3,
If you have insulation above the ceiling it will reflect the heat through the tiles upwards, the rotating vent will move slowly taking out the hot air. If there is a breeze outside it will rotate very quickly, ensuring the hot air is extracted at an even greater rate.


Ok Thank you :)
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Re: Roof Ventilation system?

Postby BKKBILL » Thu Jan 13, 2011 12:38 pm

CPAC makes a roof vent tile you could use. There are two types.

Roof tile replacement

Roof ridge tile replacement

We did this roof vent thing before.
If you go to

http://coolthaihouse.com/forum/viewtopic.php?p=4876

There are pictures and comments.

Thaifly installed one on his guest house but no close up. I remember seeing one but can't find it.

Pictures at

viewtopic.php?f=12&t=1570
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Re: Roof Ventilation system?

Postby geordie » Thu Jan 13, 2011 5:46 pm

sorry for the late reply BK BILL did a better job than me and posted a link showing some examples
can i ask why no large overhang/eaves its the traditional way but for a reason it keeps the sun out of the windows/hopefully and stops it beating down on the walls and so making the house cooler although the picture you placed shows heavy shadow is your house oriented to give the same shadow and what is happening behind it ???
You may want to consider the mediteranian/spanish solution of shutters
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Re: Roof Ventilation system?

Postby kknaj » Thu Jan 13, 2011 11:41 pm

Actually since you have roof foil AND insulation I dont see why you would need more than the usual vents in the soffits. The circulating vents are a bit overkill in my opinion. But if you really want them you can go ahead, put them somewhere that is not seen from the front of the house or where they are easily seen when outside.

In the house we just built we have a few soffit vents (with aluminum insect screens to stop bugs getting in the roof) We have one small vent on the side of the house and foil under the tiles. This seems more than enough to keep the house cool even without insulation above the ceiling.
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Re: Roof Ventilation system?

Postby geordie » Fri Jan 14, 2011 12:00 am

kknaj wrote:
In the house we just built we have a few soffit vents (with aluminum insect screens to stop bugs getting in the roof) We have one small vent on the side of the house and foil under the tiles. This seems more than enough to keep the house cool even without insulation above the ceiling.


no disrespect intended here you have done a beautiful job but funtion has to be a consideration your adequate venting now may not be so adequate in the height of summer
personally i would not be too worried about seeing the ventilation if it worked and kept me cool which is the prime reason for having it there in the first place the main aim is to have a good draw of air through the roof so venting at the soffit is important equally important is to
vent it from the ridge or as near the ridge as possible so the hot air sucks the cooler air in through the roof the spinners in my opinion are of no great value as i have never other than on a bike felt a breeze over there
my comments may be wrong but never deliberately
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Re: Roof Ventilation system?

Postby Roger Ramjet » Fri Jan 14, 2011 9:50 am

I have one on the roof of my townhouse and so does half the village, some have two or more. The newer ones make no noise and we have ours positioned at the apex of the roof. It makes the house 5 degrees cooler in the heat of summer.
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Re: Roof Ventilation system?

Postby pattayapope » Fri Jan 14, 2011 10:58 am

Roger Ramjet wrote:It makes the house 5 degrees cooler in the heat of summer.


Thats interesting Roger, on my build I wanted to install one but the builder said he had bad experiance with them leaking so I droped the idear. All the bathroom fans vent into the roof space and in the Main lounge I have a 4 meter ceiling with two decorative fans and two extractor fans to suck out any hot air. It is a bit of an experiment to see if it will keep the lounge a little cooler, I will let you know in the hot season[*] :roll:

I did think about an extractor fan in the roof to blow hot air out thru the soffits as I think is is done sometimes, anybody any knowledge of this?
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Re: Roof Ventilation system?

Postby fredlk » Fri Jan 14, 2011 11:07 am

pattayapope wrote:on my build I wanted to install one but the builder said he had bad experiance with them leaking so I droped the idea

I have one which does exactly that. It's over the top of the stair-well and when it blows and rains at the same time it splashes rain all over onto the walls and onto the floors.
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Re: Roof Ventilation system?

Postby fredlk » Fri Jan 14, 2011 11:14 am

fredlk wrote:I have one which does exactly that. It's over the top of the stair-well and when it blows and rains at the same time it splashes rain all over onto the walls and onto the floors.

IMG_0058.jpg
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