Roofing/Ventilation Works

[AnotherOneAmerican]

Two extractor fans at either end of the ridge.

Extractor high one end, one placed low at the other end of the ridge, with fan reversed.

(pull and push)

Cheap and cheerful.

Easy to fit.

Edited June 27, 2014 by AnotherOneAmerican

[evenstevens]

c/mai ,the cost of my spouts were 2,400 baht a pop (8yrs ago) sure u can find a enginering place to do the same or another model that takes your fancy

are very nice afternoon to all

[chiang mai]

The vent tile you show appears to be a CPAC product, MAGMA, the makers of my tile, stopped making the comparable tile along when they stopped making the vent tile! CPAC and MAGMA tiles are not interchangeable. I got off the phone with MAGMA Bangkok no more than an hour ago where they insisted that vented soffits alone are all that is needed, I of course cannot agree with that concept.

My plan B is that I'm going to explore hacking into a gable end to establish a vertical vent near the apex, possibly fan driven.

[evenstevens]

My plan B is that I'm going to explore hacking into a gable end to establish a vertical vent near the apex, possibly fan driven.

your o/post says u have no gable ends a pic of your roof would be great, which may help a member, to provide a answer for you

plan B ,thai workers just luv hacking into anything, would be on vigil alert ,when doing so, otherwise u will get more then u planned for

[chiang mai]

My plan B is that I'm going to explore hacking into a gable end to establish a vertical vent near the apex, possibly fan driven.

your o/post says u have no gable ends a pic of your roof would be great, which may help a member, to provide a answer for you

plan B ,thai workers just luv hacking into anything, would be on vigil alert ,when doing so, otherwise u will get more then u planned for

Yes, my error at the outset. When I first posted I had only seen the house once and was more focused on other aspects and hadn't noticed the gable at the front which is partially obscured by trees. I'll see what I can do about getting pictures but since the buying process is still underway, I'm not yet the owner and wont be so for another four weeks.

[ehs818]

Couldn't read thru all the replies, but the solution is simple. Whole house fan. Basically you buy a 60cm x 60cm heavy duty fan. Fits right into the space of the ceiling tiles. Choose a location above the stairway, Insert the fan, but hang it from the rafters for support using wire. THEN, you MUST have an exhaust vent in your attic. The hot air goes into the attic, pushing out the hotter air, and you have vertical ventilation. You can hook it up to a timer, or simply have an on'off switch connected to the electrical cord. Very easy to do. Those fans are about 2000 baht. Cost of putting in an attic vent, unknown. Good luck.

[djlissa]

Does anyone know of a contractor in Chiang Mai that installs blown-in attic insulation. I recently rented a small house and only visited early in the day before renting and the attic turns into an oven and heats the house all night long. Poor AC runs all night and can't really keep up. I know stupid me. I can't even find any access to the attic and zero vents up top.

Any help will greatly appreciated.

Denny

[tpthai2]

Thanks to the CM poster that recommended this:

Hatari ventilators ceiling model HT-VC25M1 (G) - Ivory White.

http://www.lazada.co...ite-861889.html

We have a standard 3Bd/3Bath two story. 4 gables on each floor,

standard foil under the tiles.

Mounted one of these in the roof access square on the top floor.

Went from hot as hell to it's warm up here in a few hours of use.

I would say 6 or 7+ degree drop.

Less than 1,000 bt.

[teatree]

Are you sure that's a good idea, the air inside the house on the lower floors is likely to be the coolest air of any and as your vent removes it, it will be replaced with warmer air from outside? That method also precludes the use of aircon in the living rooms.

Wouldn't the air outside be cooler? Air inside a house is warmer than outside in my experience, the house itself doesn't have a cooling effect - quite the opposite I would have thought.

The air downstairs is just cooler in comparison.

With regards to the aircon, provided there is an air source upstairs and the windows are closed downstairs, wouldn't the air be pulled from the upstairs source? The cool air from the aircon likes to hang low.

I have been considering what the poster you replied to was writing about i.e. an extractor fan in the ceiling blowing air to the loft and then a vent in the roof to dispel the hot air outside.

[sandyf]

I have both turbine vents and PU foam spray under the tiles. The PU foam spray under the tiles is GREAT and, for this climate, far, far better than insulation over the ceiling. If you would like to know more, PM me. I will surely get flamed on this forum for saying PU foam is better that ceiling insulation, so I am finished here.

The theory sounds good, but heat rises hence trying to create positive pressure inside the roof void is not likely to force the hot air downwards and out through the soffits, dunno, this sounds like one for Herr Naam. But as you say, if it fails then reverting to the status quo is cheap and easy so you're probably right to give it a shot.

Also, am wondering if anyone has tried spray on foam to the underside of the roof, the theory being that it prevents/reduces heat transfer from the CPAC into the roof void. That's another one where the theory sounds good but at 500 baht a square metre it needs to be proven before actually doing it.

Just as a matter of interest what was the rough cost of the foam? I looked at this about10 years ago and a very nice chap came to the house to give me a quote. I politely declined after picking myself up off the floor. If the price has reduced it may be worth doing.

I'm sure that poster will reply, in the meantime, the costs I have seen from two companies recently in northern Thailand are between THB 500 and THB 700 a square metre.

Probably about right price wise. Quote I had when I was building my house, unfortunately the budget did not stretch that far.

roof spray_a.pdf

[chiang mai]

Are you sure that's a good idea, the air inside the house on the lower floors is likely to be the coolest air of any and as your vent removes it, it will be replaced with warmer air from outside? That method also precludes the use of aircon in the living rooms.

Wouldn't the air outside be cooler? Air inside a house is warmer than outside in my experience, the house itself doesn't have a cooling effect - quite the opposite I would have thought.

The air downstairs is just cooler in comparison.

With regards to the aircon, provided there is an air source upstairs and the windows are closed downstairs, wouldn't the air be pulled from the upstairs source? The cool air from the aircon likes to hang low.

I have been considering what the poster you replied to was writing about i.e. an extractor fan in the ceiling blowing air to the loft and then a vent in the roof to dispel the hot air outside.

I have two thermometers set up to measure temperature, one in the living room and one under the front porch, the numbers currently are 26 degrees and 32 degrees, respectively. I suppose the air inside the house remains cool from overnight and is slower to heat up throughout the day, the air on the outside is heated directly by the sun and is convected into even shaded areas, such as my front porch.

Re. aircon: hot air rises and is unable to defeat the cool layer beneath is caused by the downstairs aircon. So no, the hot air upstairs would not be pulled downstairs as a result of suing downstairs aircon with the windows closed - aircon only needs air, it doesn't need to be warmer air it can simply re-cool cooler air.

But since I started this thread last year, things have moved on. I have now finished enlarging the gable exhaust vents to provide for a total of 7 square feet of exhaust ventilation. I've also installed vented soffits around the eves which supplies a further 7 square feet of cooler input air - I've also installed a radiant barrier to reduce/eliminate heat radiated from roof tiles, onto the ceilings below - up to twelve inches of bat type insulation has also been laid. Finally, I'm in the process of installing a 1600 cubic feet per minute exhaust fan into one of the gable vents, if ever I can find one I intend to hook it up to a thermostatic switch so that when the attic temperature reaches say 95 degrees, the fan will kick in.

[LivinLOS]

I am pretty sure I can guess but..

u are always welcome to drop in,to have a bow peep just p.m

That would translate to 'sleep' doesnt it ??

[MastaMak]

I'm also looking for a similar solution.

It has been asked before, but does no one import / build solar attic fans in Thailand? With the heat and amount of sun you would think it is a no brainer for any house?

Looking for something like that, looks good and is basically free since it uses solar power:

http://www.solatube.com/residential/solar-star

[chiang mai]

I'm also looking for a similar solution.

It has been asked before, but does no one import / build solar attic fans in Thailand? With the heat and amount of sun you would think it is a no brainer for any house?

Looking for something like that, looks good and is basically free since it uses solar power:

http://www.solatube.com/residential/solar-star

I've looked hard and never found them, I couldn't even find an attic fan on a thermo. switch!

[evenstevens]

I am pretty sure I can guess but..

u are always welcome to drop in,to have a bow peep just p.m

That would translate to 'sleep' doesnt it ??

uuuhhh?????whats your point cobber

[LivinLOS]

just not heard it used that way.. Boo Peep = Sleep..

[teatree]

Are you sure that's a good idea, the air inside the house on the lower floors is likely to be the coolest air of any and as your vent removes it, it will be replaced with warmer air from outside? That method also precludes the use of aircon in the living rooms.

Wouldn't the air outside be cooler? Air inside a house is warmer than outside in my experience, the house itself doesn't have a cooling effect - quite the opposite I would have thought.

The air downstairs is just cooler in comparison.

With regards to the aircon, provided there is an air source upstairs and the windows are closed downstairs, wouldn't the air be pulled from the upstairs source? The cool air from the aircon likes to hang low.

I have been considering what the poster you replied to was writing about i.e. an extractor fan in the ceiling blowing air to the loft and then a vent in the roof to dispel the hot air outside.

I have two thermometers set up to measure temperature, one in the living room and one under the front porch, the numbers currently are 26 degrees and 32 degrees, respectively. I suppose the air inside the house remains cool from overnight and is slower to heat up throughout the day, the air on the outside is heated directly by the sun and is convected into even shaded areas, such as my front porch.

Re. aircon: hot air rises and is unable to defeat the cool layer beneath is caused by the downstairs aircon. So no, the hot air upstairs would not be pulled downstairs as a result of suing downstairs aircon with the windows closed - aircon only needs air, it doesn't need to be warmer air it can simply re-cool cooler air.

But since I started this thread last year, things have moved on. I have now finished enlarging the gable exhaust vents to provide for a total of 7 square feet of exhaust ventilation. I've also installed vented soffits around the eves which supplies a further 7 square feet of cooler input air - I've also installed a radiant barrier to reduce/eliminate heat radiated from roof tiles, onto the ceilings below - up to twelve inches of bat type insulation has also been laid. Finally, I'm in the process of installing a 1600 cubic feet per minute exhaust fan into one of the gable vents, if ever I can find one I intend to hook it up to a thermostatic switch so that when the attic temperature reaches say 95 degrees, the fan will kick in.

Where are the living room and porch facing? If the living room is facing east and the porch west, that could explain the difference in temperature.

About the A/C, I meant in my previous post that if there was an air source upstairs (open window), under/near the exhaust ceiling fan, would the air not be pulled from there rather than from downstairs, meaning that the effect on the A/C downstairs would be minimal? I wasn't saying the air would from upstairs would be pulled downstairs.

If I had gables as you do then I think your set up is the best way to go about cooling the loft, but I don't. I'll probably give the ceiling fan/twirly bird a go and report back.

Edited October 15, 2015 by teatree

[chiang mai]

Are you sure that's a good idea, the air inside the house on the lower floors is likely to be the coolest air of any and as your vent removes it, it will be replaced with warmer air from outside? That method also precludes the use of aircon in the living rooms.

Wouldn't the air outside be cooler? Air inside a house is warmer than outside in my experience, the house itself doesn't have a cooling effect - quite the opposite I would have thought.

The air downstairs is just cooler in comparison.

With regards to the aircon, provided there is an air source upstairs and the windows are closed downstairs, wouldn't the air be pulled from the upstairs source? The cool air from the aircon likes to hang low.

I have been considering what the poster you replied to was writing about i.e. an extractor fan in the ceiling blowing air to the loft and then a vent in the roof to dispel the hot air outside.

I have two thermometers set up to measure temperature, one in the living room and one under the front porch, the numbers currently are 26 degrees and 32 degrees, respectively. I suppose the air inside the house remains cool from overnight and is slower to heat up throughout the day, the air on the outside is heated directly by the sun and is convected into even shaded areas, such as my front porch.

Re. aircon: hot air rises and is unable to defeat the cool layer beneath is caused by the downstairs aircon. So no, the hot air upstairs would not be pulled downstairs as a result of suing downstairs aircon with the windows closed - aircon only needs air, it doesn't need to be warmer air it can simply re-cool cooler air.

But since I started this thread last year, things have moved on. I have now finished enlarging the gable exhaust vents to provide for a total of 7 square feet of exhaust ventilation. I've also installed vented soffits around the eves which supplies a further 7 square feet of cooler input air - I've also installed a radiant barrier to reduce/eliminate heat radiated from roof tiles, onto the ceilings below - up to twelve inches of bat type insulation has also been laid. Finally, I'm in the process of installing a 1600 cubic feet per minute exhaust fan into one of the gable vents, if ever I can find one I intend to hook it up to a thermostatic switch so that when the attic temperature reaches say 95 degrees, the fan will kick in.

Where are the living room and porch facing? If the living room is facing east and the porch west, that could explain the difference in temperature.

About the A/C, I meant in my previous post that if there was an air source upstairs (open window), under/near the exhaust ceiling fan, would the air not be pulled from there rather than from downstairs, meaning that the effect on the A/C downstairs would be minimal? I wasn't saying the air would from upstairs would be pulled downstairs.

If I had gables as you do then I think your set up is the best way to go about cooling the loft, but I don't. I'll probably give the ceiling fan/twirly bird a go and report back.

Both West facing.

[chiang mai]

Just to wrap this up: I checked the temperatures again this morning and they were almost the same, 26 and 32. But if I open the sliding doors in the living room for an hour, the inside temperature increases to within 2 degrees of the outside air, caused presumably by external convected air. But then if the doors are closed again and the source of hot air closed off, the internal room temperature drops back to 26 degrees within half an hour. This is presumably caused by 1 - removing the source of heat and 2 - allowing the warmer air in the living room to be offset by the cooler air in the rest of the house. All of this without aircon, just in case somebody was wondering!

I think what this says is that as long as your property is well insulated and the sources of heat removed, the inside air temperature can remain significantly cooler (resulting from the night before) than the outside air. At some point in the day however, if the outside temperature rises significantly and/or the sun takes a different (seasonal) path through the sky, the insulation will be defeated and the internal temperature will rise.

OK, you need to remember all of this because there'll be a quiz later.

[sandyf]

I think what this says is that as long as your property is well insulated and the sources of heat removed, the inside air temperature can remain significantly cooler (resulting from the night before) than the outside air. At some point in the day however, if the outside temperature rises significantly and/or the sun takes a different (seasonal) path through the sky, the insulation will be defeated and the internal temperature will rise.

OK, you need to remember all of this because there'll be a quiz later.

It is all about how the building is constructed, how you use the aircon and live during the day.

Concrete is a hidden asset, if you have a solid concrete floor it will act like a storage heater in reverse. If however you have large windows and doors and during the day they are wide open the stored negative heat will soon dissipate. You also need to run the aircon regularly to top up the stored negative heat.

I have cavity wall construction and solid concrete floors and the internal temperature is well below the outside ambient. I couldn't afford the foam insulation and had to settle for roof vents at each end but I am glad now that I saved the money.

[chiang mai]

I only partially agree, my house is raised up from the ground by about one metre hence the reverse storage heater concept you describe does not apply.

Overnight the house cools, the trick is to retain that reduction of heat as long as possible, throughout the following day.

The heat source is from above therefore the key issue is to prevent that heat from entering the living space and heating the cooler air, attic ventilation and ceiling insulation are key elements in that.

Secondary is to prevent the heat source from penetrating windows and walls, reflective window film, overhanging eves and external blinds all work well, all of which I have deployed.

A last resort measure of course is an attic exhaust air extractor fan, that to be used if/when the insulation has been defeated.

[a99az]

I fixed the problem of excessive heat up stairs by putting in two very large roof vents and insulating above the ceiling. Fresh air is drawn in from the underside of the roof overhang. Massive improvement.

[sandyf]

I only partially agree, my house is raised up from the ground by about one metre hence the reverse storage heater concept you describe does not apply.

Overnight the house cools, the trick is to retain that reduction of heat as long as possible, throughout the following day.

The heat source is from above therefore the key issue is to prevent that heat from entering the living space and heating the cooler air, attic ventilation and ceiling insulation are key elements in that.

Secondary is to prevent the heat source from penetrating windows and walls, reflective window film, overhanging eves and external blinds all work well, all of which I have deployed.

A last resort measure of course is an attic exhaust air extractor fan, that to be used if/when the insulation has been defeated.

If you are up on stilts then you will not have the thermal mass available to utilise. You are quite right that you have to try and prevent heat penetration, that's is why I had cavity wall construction, bricks externally with Q block internally. I also kept the windows quite small and it all worked out quite well.

At the end of the day, you cannot bring the internal temperature down below the outside ambient without mechanical intervention, creating draughts helps but not a solution.