Do These Roof Exhaust Fans Let In The Rain?

[UKJASE]

Hey guys, you know the rotating roof exhaust fans for letting out the hot air from the roof....

they look like this - http://i00.i.aliimg.com/photo/v1/485639682/600mm_Non_Power_Exhaust_Fan_Roof_Vent.jpg

does anyone know if they let in rain water when positioned on top of the roof? they seem to be open to the elements, so i imagine in a windy storm, they could let in lots of water

Also, any other tips on how to get the most from one?

[stoneyboy]

Had them in Thornaby,leaked like a cheap umbrella.

[eyecatcher]

Well they shouldn't.

Designers don't spend years designing and obtaining patents for a proprietary piece of kit that fails against the basic wind, rain, snow,sun.

My educated guess is that they leak when they have been installed incorrectly.

Then again my experience and education is all about construction so what do I know.

[UKJASE]

Well they shouldn't.

Designers don't spend years designing and obtaining patents for a proprietary piece of kit that fails against the basic wind, rain, snow,sun.

My educated guess is that they leak when they have been installed incorrectly.

Then again my experience and education is all about construction so what do I know.

yea you said it eyecatcher

designers here "dont spend years designing and obtaining patents"....... that is why i am thinking that they might leak.....

i mean they are open to let the air flow out easily...... so wouldnt the rain flow back in just as easy?

[eyecatcher]

With due respect. These roof contraptions are not designed by thais, they are more often than not a western import so my point about design is valid.

I will assume you know how they work but for those who don't.

They draw air from the roof via split vanes when they are operational.

When they are spinning the design of the vanes and the centrifugal forces cause any water to be thrown out.

You don't even have to have them switched on because more often than not rain is usually accompanied by wind, prior to rain.

The wind spins the head and stops rain or snow getting in.

What you would need to do is to check,grease,oil the ball bearings to ensure easy spinning.

So If I may reiterate, if rain is penetrating leaking then I doubt very much its the terminal head and more likely bad fitting or minor maintenance.

[ClutchClark]

This type of vent is typically used as a vent for a kitchen flue or a chimney and in such applications, the water that gets inside travels within the chimney and into a clean-out at the lower extremity.

It is not typical, nor is it designed, for an attic vent because it will do exactly as you were keen enough to identify.

Choosing the proper vent for the application is critical and if you are trying to vent your attic space then there was an excellent thread running just in the last couple weeks.

Cheers

[kkerry]

Some people say they work, others reckon they're a waste of money.

Got a couple in our house and they make a difference in the area we put them that was previously like an oven. Never had any issues with rain. Just be sure they're in a spot where the wind can get to them and not a dead spot e.g. airflow blocked by surrounding taller buildings.

[ClutchClark]

Some people say they work, others reckon they're a waste of money.

Got a couple in our house and they make a difference in the area we put them that was previously like an oven. Never had any issues with rain. Just be sure they're in a spot where the wind can get to them and not a dead spot e.g. airflow blocked by surrounding taller buildings.

These are not designed to be "wind-driven". They are designed to be powered by the force (pressure) of the hot exhaust air created by a hot stove or furnace.

If you use them for venting an attic space, then its an application they were not designed for and they will most always leak.

Furthermore, they are designed to be installed level to the horizon. If you install one parallel to the pitch of the roof because you are venting the attic then they will leak all the worse.

[David48]

We did a bedroom renovation, raised the roof, new tiles, now we have a ceiling ... new for a typicial Thai house.

I has happy to pay for the said roof vent.

The Man who owns the house (my gf's old man) basicially said NO.

No, as in they leak.

gf also had them at her work ... reckons they leaked there also.

One thing that I notice here in Thailand is that they are built slightly differently.

In Australia they are designed with a twistable shaft which compensates for the roof pitch ...

In Thailand, the one I did buy (another place) just had a straight, non-adjustible shaft (unlike the photo above).

Hence they spin parallel to the roof line and not to ground line.

Apart from that difference ... no idea why.

Edited July 4, 2014 by David48

[Tywais]

We have them in one of our research buildings at the university and they work fine. Considering the amount of very expensive systems plus very high voltage systems, hundreds of kV, in the building installing them was not taken likely. Had no problems with water entering the building from them. Also have them in a large storage area at work and also no issues. Proper choice of a quality vent and proper installation than they should work fine. None are motorized, all move via thermal venting.

[sotsira]

UKJase, here's a few ideas for you to look at:-

Edited July 4, 2014 by sotsira

[David48]

We have them in one of our research buildings at the university and they work fine. Considering the amount of very expensive systems plus very high voltage systems, hundreds of kV, in the building installing them was not taken likely. Had no problems with water entering the building from them. Also have them in a large storage area at work and also no issues. Proper choice of a quality vent and proper installation than they should work fine. None are motorized, all move via thermal venting.

Flat or pitched roof?

[ClutchClark]

Gents,

My apologies. I googled and found that some regions of the US do actually use turbine vents for attic space.

I am only guessing in "arid" regions.

As a contractor, I would never have even considered building a home with one of these because they do leak more than any other roof vent I have seen, they do blow off in high winds, and the bearings do lose lubrication and make alot of noise and quit spinning freely. These were all warranty calls when they used in commercial applications (restaurant kitchens) on flat roofs.

I had best leave this topic for builders & homeowners who actually use and think highly of these as attic space vents in Thailand. ;-)

Cheers

Edited July 4, 2014 by ClutchClark

[wpcoe]

Those vents like pictured in the OP: are the spun by the outdoors wind passing by, or are they spun by heat convection currents rising within the vacant attic space beneath the vent? I seem to have heard both versions...

[UKJASE]

it seems like the jury is hung on this one....... bu**er..... maybe to be on the safe side i better leave them alone.... admittedly they dont look great, and our house is in the countryside, by a lovely lake, so maybe the vent would not be so aesthetically pleasing

maybe i will use internal extractor fans at either gable end, plus maybe some ducting to shift the air from the centre of the roof to the edges, and out the gable vents

can i ask one other question.... lots of people talk about vented ridge tiles.... we have ordered CPAC monier and the ridge tiles will be delivered on monday.... does anyone know if all CPAC monier ridge tiles are vented, or will we have to especially order them?

[David48]

Mate, maybe a PM to IMHO.

He's Thai, his old man's in the building game.

Has a wealth of experience and he's a nice an approacable guy to boot.

[lopburi3]

We have had two units on main house for more than 20 years and another above cooking area of semi-outdoor cooking area for last 10 years (replaced high powered restaurant type unit) and after initial installation leakage due to not sealing flashing correctly (on 20 year old main roof) have not had any issues and the one above stove is easy to see and does not leak more than a drop or two. It made a huge difference in 2nd floor air conditioning getting the hot air out of attic. As for pitch they are built with that taken into account so you buy for the type of roof you have or they make for you. There are shops equipped to do so everywhere.

This post has been double checked with 'she who knows' who approves content. Almost no leakage even in heavy rain storms.

[IMHO]

it seems like the jury is hung on this one....... bu**er..... maybe to be on the safe side i better leave them alone.... admittedly they dont look great, and our house is in the countryside, by a lovely lake, so maybe the vent would not be so aesthetically pleasing

maybe i will use internal extractor fans at either gable end, plus maybe some ducting to shift the air from the centre of the roof to the edges, and out the gable vents

can i ask one other question.... lots of people talk about vented ridge tiles.... we have ordered CPAC monier and the ridge tiles will be delivered on monday.... does anyone know if all CPAC monier ridge tiles are vented, or will we have to especially order them?

Here's what the CPAC Monier vented ridge cap looks like:

Standard ridge caps aren't ventilated.

The standard passive methods to ventilate the roof cavity in TH are ventilated soffits, and gable vents, and the primary defence against a hot roof is radiant foil...

If you really want to implement "convection" cooling for the roof, in a way that's both effective and aesthetically pleasing, you might want to consider s design like this:

Note the small "hat" on the left - and the big "hat" on the right.

Edited July 5, 2014 by IMHO

[Naam]

Some people say they work, others reckon they're a waste of money.

Got a couple in our house and they make a difference in the area we put them that was previously like an oven. Never had any issues with rain. Just be sure they're in a spot where the wind can get to them and not a dead spot e.g. airflow blocked by surrounding taller buildings.

These are not designed to be "wind-driven". They are designed to be powered by the force (pressure) of the hot exhaust air created by a hot stove or furnace.

If you use them for venting an attic space, then its an application they were not designed for and they will most always leak.

Furthermore, they are designed to be installed level to the horizon. If you install one parallel to the pitch of the roof because you are venting the attic then they will leak all the worse.

-they are designed to be driven by wind/breeze,

-if there is no wind then they even hamper the flow of air,

-if properly installed they do not let rain in,

-they are not as efficient as a powered exhaust fan

but

-they do not use any costly energy.

[Naam]

We did a bedroom renovation, raised the roof, new tiles, now we have a ceiling ... new for a typicial Thai house.

I has happy to pay for the said roof vent.

The Man who owns the house (my gf's old man) basicially said NO.

No, as in they leak.

gf also had them at her work ... reckons they leaked there also.

One thing that I notice here in Thailand is that they are built slightly differently.

In Australia they are designed with a twistable shaft which compensates for the roof pitch ...

In Thailand, the one I did buy (another place) just had a straight, non-adjustible shaft (unlike the photo above).

Hence they spin parallel to the roof line and not to ground line.

Apart from that difference ... no idea why.

adjustable shafts are available in Thailand.

[chiang mai]

it seems like the jury is hung on this one....... bu**er..... maybe to be on the safe side i better leave them alone.... admittedly they dont look great, and our house is in the countryside, by a lovely lake, so maybe the vent would not be so aesthetically pleasing

maybe i will use internal extractor fans at either gable end, plus maybe some ducting to shift the air from the centre of the roof to the edges, and out the gable vents

can i ask one other question.... lots of people talk about vented ridge tiles.... we have ordered CPAC monier and the ridge tiles will be delivered on monday.... does anyone know if all CPAC monier ridge tiles are vented, or will we have to especially order them?

Here's what the CPAC Monier vented ridge cap looks like:

Standard ridge caps aren't ventilated.

The standard passive methods to ventilate the roof cavity in TH are ventilated soffits, and gable vents, and the primary defence against a hot roof is radiant foil...

If you really want to implement "convection" cooling for the roof, in a way that's both effective and aesthetically pleasing, you might want to consider s design like this:

1b.jpg

Note the small "hat" on the left - and the big "hat" on the right.

That is not the vented ridge tile, it's a tile designed to vent a specific unit to the outside such as an antennae or similar, as per the picture.

The CPAC vented ridge tile is a standard ridge tile that has cutouts along the long sides of the tile to allow warmer air to vent, there are sample set ups of them in many hardware/DIY shops that sell CPAC - it's designed to be screwed to the metal cross beam at the ridge rather than cemented in. Also, the vent pipe tile is special order and takes three months for delivery.

Post 11, top left corner picture describes the ridge tile vent concept.

Edited July 6, 2014 by chiang mai

[chiang mai]

If you google:

https://www.google.co.th/search?q=ridge+tile+vents&client=firefox-a&hs=eKc&rls=org.mozilla:en-US:official&channel=sb&tbm=isch&imgil=MnKmop2_SeBBjM%253A%253Bhttps%253A%252F%252Fencrypted-tbn2.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcRsqY5ix7KSc1-YQpSip9AFdM3jsVNu5lUJIqKLqDEicU_B35lXFA%253B570%253B450%253Bqc3M40sYvKaTkM%253Bhttp%25253A%25252F%25252Fwww.heidelbergcement.com%25252Fuk%25252Fen%25252Fhanson%25252Fproducts%25252Fchimney_and_roofing%25252Fridge_products%25252Fridge_ventilation_system.htm&source=iu&usg=__WHHy6VxzwUqqtg2GiH1QNT8WxfE%3D&sa=X&ei=-Ju4U5aDEJXj8AWqjoK4BQ&ved=0CD4Q9QEwAg&biw=1268&bih=856#facrc=_&imgdii=_&imgrc=MnKmop2_SeBBjM%253A%3Bqc3M40sYvKaTkM%3Bhttp%253A%252F%252Fwww.heidelbergcement.com%252FNR%252Frdonlyres%252F525394F7-9753-4CC3-BDD6-AEFB1CB6FE1E%252F0%252Fridge_ventilation_570.jpg%3Bhttp%253A%252F%252Fwww.heidelbergcement.com%252Fuk%252Fen%252Fhanson%252Fproducts%252Fchimney_and_roofing%252Fridge_products%252Fridge_ventilation_system.htm%3B570%3B450

There's loads of pictures of ridge tile vents that may even give you some ideas, the Australian market has loads of after market products.

[IMHO]

it seems like the jury is hung on this one....... bu**er..... maybe to be on the safe side i better leave them alone.... admittedly they dont look great, and our house is in the countryside, by a lovely lake, so maybe the vent would not be so aesthetically pleasing

maybe i will use internal extractor fans at either gable end, plus maybe some ducting to shift the air from the centre of the roof to the edges, and out the gable vents

can i ask one other question.... lots of people talk about vented ridge tiles.... we have ordered CPAC monier and the ridge tiles will be delivered on monday.... does anyone know if all CPAC monier ridge tiles are vented, or will we have to especially order them?

Here's what the CPAC Monier vented ridge cap looks like:

Standard ridge caps aren't ventilated.

The standard passive methods to ventilate the roof cavity in TH are ventilated soffits, and gable vents, and the primary defence against a hot roof is radiant foil...

If you really want to implement "convection" cooling for the roof, in a way that's both effective and aesthetically pleasing, you might want to consider s design like this:

1b.jpg

Note the small "hat" on the left - and the big "hat" on the right.

That is not the vented ridge tile, it's a tile designed to vent a specific unit to the outside such as an antennae or similar, as per the picture.

The CPAC vented ridge tile is a standard ridge tile that has cutouts along the long sides of the tile to allow warmer air to vent, there are sample set ups of them in many hardware/DIY shops that sell CPAC - it's designed to be screwed to the metal cross beam at the ridge rather than cemented in. Also, the vent pipe tile is special order and takes three months for delivery.

Post 11, top left corner picture describes the ridge tile vent concept.

I can't see anything like that in the CPAC product guides.. got a link to a Thai supplier?

[chiang mai]

it seems like the jury is hung on this one....... bu**er..... maybe to be on the safe side i better leave them alone.... admittedly they dont look great, and our house is in the countryside, by a lovely lake, so maybe the vent would not be so aesthetically pleasing

maybe i will use internal extractor fans at either gable end, plus maybe some ducting to shift the air from the centre of the roof to the edges, and out the gable vents

can i ask one other question.... lots of people talk about vented ridge tiles.... we have ordered CPAC monier and the ridge tiles will be delivered on monday.... does anyone know if all CPAC monier ridge tiles are vented, or will we have to especially order them?

Here's what the CPAC Monier vented ridge cap looks like:

Standard ridge caps aren't ventilated.

The standard passive methods to ventilate the roof cavity in TH are ventilated soffits, and gable vents, and the primary defence against a hot roof is radiant foil...

If you really want to implement "convection" cooling for the roof, in a way that's both effective and aesthetically pleasing, you might want to consider s design like this:

1b.jpg

Note the small "hat" on the left - and the big "hat" on the right.

That is not the vented ridge tile, it's a tile designed to vent a specific unit to the outside such as an antennae or similar, as per the picture.

The CPAC vented ridge tile is a standard ridge tile that has cutouts along the long sides of the tile to allow warmer air to vent, there are sample set ups of them in many hardware/DIY shops that sell CPAC - it's designed to be screwed to the metal cross beam at the ridge rather than cemented in. Also, the vent pipe tile is special order and takes three months for delivery.

Post 11, top left corner picture describes the ridge tile vent concept.

I can't see anything like that in the CPAC product guides.. got a link to a Thai supplier?

No, I've looked and can't find an exact picture match. The ridge tile looks like a standard pointed ridge tile except it stands on four feet thus creating an air gap, I've seen it in the flesh at Home Works (?) on the ring road in Chiang Mai, just up from the Central Festival where they have a roof display set up with all the options, if I'm passing there I'll stop and take a picture and post it. BTW it's designed to be used with foil backed against the tiles in order to provide a vent for the hot air in the gap.

[UKJASE]

Here's what the CPAC Monier vented ridge cap looks like:

Standard ridge caps aren't ventilated.

The standard passive methods to ventilate the roof cavity in TH are ventilated soffits, and gable vents, and the primary defence against a hot roof is radiant foil...

If you really want to implement "convection" cooling for the roof, in a way that's both effective and aesthetically pleasing, you might want to consider s design like this:

1b.jpg

Note the small "hat" on the left - and the big "hat" on the right.

That is not the vented ridge tile, it's a tile designed to vent a specific unit to the outside such as an antennae or similar, as per the picture.

The CPAC vented ridge tile is a standard ridge tile that has cutouts along the long sides of the tile to allow warmer air to vent, there are sample set ups of them in many hardware/DIY shops that sell CPAC - it's designed to be screwed to the metal cross beam at the ridge rather than cemented in. Also, the vent pipe tile is special order and takes three months for delivery.

Post 11, top left corner picture describes the ridge tile vent concept.

I can't see anything like that in the CPAC product guides.. got a link to a Thai supplier?

No, I've looked and can't find an exact picture match. The ridge tile looks like a standard pointed ridge tile except it stands on four feet thus creating an air gap, I've seen it in the flesh at Home Works (?) on the ring road in Chiang Mai, just up from the Central Festival where they have a roof display set up with all the options, if I'm passing there I'll stop and take a picture and post it. BTW it's designed to be used with foil backed against the tiles in order to provide a vent for the hot air in the gap.

Hey guys - i went to the Home Mart in Cha Am yesterday, and saw the cpac vent tiles in there on the roof display set up. as described above they have the sides cut away 2 or 3 cm and the bottom corners remain, and i can see they will allow good air flow

the only thing was, they sales guy told us that we would need to buy some rolls of rubber seal to put on top of the ridge. this stops the rain coming in, but has some small holes in to let the air vent out. i didnt know if he was just doing the sales pitch thing. i looked at the vents and they do hang over the edges quite far, thus stopping vertical falling rain from entering the roof space. i am not sure what they would be like on a windy day

the rubber was 1450 B for 3 metres, so we didnt buy any yet

do you guys know if the roof needs sealing on the top with rubber etc? the guy said if we were cementing the top ridge tiles down, then rubber is not needed, but if we were screwing them in position, then we should buy the rubber

[chiang mai]

Great, for everyone else, the product is made by CPAC Monier and is the Trachang brand, as said, Home Mart is the stockist..

And if I was going to use that product I would simply cement it into place, just like a normal ridge tile but obviously leaving the air gaps open.

Edited July 6, 2014 by chiang mai

[UKJASE]

Great, for everyone else, the product is made by CPAC Monier and is the Trachang brand, as said, Home Mart is the stockist..

And if I was going to use that product I would simply cement it into place, just like a normal ridge tile but obviously leaving the air gaps open.

would you think the rain would likely blow under these tiles during a windy storm Chiang Mai? the guy in Home mart told us we should buy the rubber seal too to go with the tiles, that had air holes already punched through

it was quite hard to judge from the display tiles in the shop, if the rubber would be necessary or not. i guess without the rubber, a better airflow would be achieved, but if the rain leaked in sometimes, i would be in for the chop from the Mrs

[chiang mai]

Great, for everyone else, the product is made by CPAC Monier and is the Trachang brand, as said, Home Mart is the stockist..

And if I was going to use that product I would simply cement it into place, just like a normal ridge tile but obviously leaving the air gaps open.

would you think the rain would likely blow under these tiles during a windy storm Chiang Mai? the guy in Home mart told us we should buy the rubber seal too to go with the tiles, that had air holes already punched through

it was quite hard to judge from the display tiles in the shop, if the rubber would be necessary or not. i guess without the rubber, a better airflow would be achieved, but if the rain leaked in sometimes, i would be in for the chop from the Mrs

If you're looking at the one metre strips of rubber that have vent holes already punched in, they are typically used at the eves level and not at the peak, they are contoured to follow the shape of the tiles?

From looking at the display it seems that water ingress from blown rain at the peak is unlikely, it must depend however on how far down the roof the first row of tiles starts, as long as there's a decent overlap between the ridge tile and the topmost course I can't see it being a problem. Putting in a layer of rubber can't be helpful to venting the hot air, it's not as though you can create a one way flap. But I think I probably would put a layer of mesh under the tile to prevent creepies and bugs etc from making home in your attic.

[IMHO]

Great, for everyone else, the product is made by CPAC Monier and is the Trachang brand, as said, Home Mart is the stockist..

And if I was going to use that product I would simply cement it into place, just like a normal ridge tile but obviously leaving the air gaps open.

would you think the rain would likely blow under these tiles during a windy storm Chiang Mai? the guy in Home mart told us we should buy the rubber seal too to go with the tiles, that had air holes already punched through

it was quite hard to judge from the display tiles in the shop, if the rubber would be necessary or not. i guess without the rubber, a better airflow would be achieved, but if the rain leaked in sometimes, i would be in for the chop from the Mrs

Perhaps the sales rep was showing you the "Dry Tech" system?

We now use this exclusively - no more using cement on ridges, and no more problems with cement cracks and leaks.

[UKJASE]

Great, for everyone else, the product is made by CPAC Monier and is the Trachang brand, as said, Home Mart is the stockist..

And if I was going to use that product I would simply cement it into place, just like a normal ridge tile but obviously leaving the air gaps open.

would you think the rain would likely blow under these tiles during a windy storm Chiang Mai? the guy in Home mart told us we should buy the rubber seal too to go with the tiles, that had air holes already punched through

it was quite hard to judge from the display tiles in the shop, if the rubber would be necessary or not. i guess without the rubber, a better airflow would be achieved, but if the rain leaked in sometimes, i would be in for the chop from the Mrs

Perhaps the sales rep was showing you the "Dry Tech" system?

We now use this exclusively - no more using cement on ridges, and no more problems with cement cracks and leaks.

yes, that is teh exact system the sales rep was showing us IMHO

it seems quite expensive at 1450 B for 3 meters. is there a cheaper alternative system that you know about mate?