Cool Roof – What’s The Best?

[Beachcomber]

Hi

In the LOS it can get HOT. What is the best kind of roof to have on your house to try keep the inside temperature down?

I would hazard a guess that the coolest roof would be a made from Nipa Palm fronds or the Cogon grass. But they require lot of maintenance. Corrugated tin is cheap but very hot.

Any one have practical experience on this subject. Please don’t say get AC.

On one of my travels up north somewhere, can’t remember where, I noticed a lot of shops had a water sprinkler system over their roofs to keep cool. I guess it worked for them but what would be the cost and do you recycle the same water or use fresh water?

Thanks

[tutsiwarrior]

Hi

In the LOS it can get HOT. What is the best kind of roof to have on your house to try keep the inside temperature down?

I would hazard a guess that the coolest roof would be a made from Nipa Palm fronds or the Cogon grass. But they require lot of maintenance. Corrugated tin is cheap but very hot.

Any one have practical experience on this subject. Please don’t say get AC.

On one of my travels up north somewhere, can’t remember where, I noticed a lot of shops had a water sprinkler system over their roofs to keep cool. I guess it worked for them but what would be the cost and do you recycle the same water or use fresh water?

Thanks

lots about this subject in the real estate, housing, etc forum...jus scroll down and do a search

a sprinkler system to beat A/C???

well, there are also various types of shade trees...a hammock and a sleeping bag wouldn't go amiss...

also look at www.coolthaihouse.com

[Youbloodybeauty]

In the LOS it can get HOT

Have a look through this:

Passive cooling home design

and this:

Earth sheltered house

YBB

[CGW]

Blue, tile? roof would be a start, blue being the second coolest, keast heat absorbing colour next to white!

[Sir Burr]

Blue, tile? roof would be a start, blue being the second coolest, keast heat absorbing colour next to white!

The larger the volume of the roof, the cooler the house. Thai-style rooves are high volume.

You also need adequate ventilation.

Heat absorbtion of roof-tiles has nothing to do with colour, but their shade. The darker it is, the more efficient it's heat absorbsion. You need light coloured tiles.

[tyler2uk]

Use light blue diamond brand tiles. get good gable end vents. and maybe fit soffitt vents in the overhang.

How many gable end vent and soffits depends on the roof you have of course.

don't put any insulation at ceilling level as you need heat that has risen to escape out of room and then out of the roof space.

Use reflective foil under the tiles and if you want to go the full hog you can wire each tile to the roof at the top to raise the lower edge so the heat can get out..(BUT this wont help with insects )

Also use raised raft foundations and fit vent bricks BELOW the foundation, a raised foundation will not rot and is equally strong (same as multi-story car park in design) this will allow air to flow under the house.

We now have a cool house and have no need for a A.C.

The trick is to allow the hot air that is trapped in the roofspace out because if you dont it will eventually radiate down on to you. good luck

[solo siam]

Just use some decent insulation in the above ceiling area (seal it completely) and some of the silver foil on the inside of the light coloured roof and that should be fine, Have a rood that overhangs the windows, air-cons etc... that helps keep heat from radiatig through the windows or falling on the AC Fan.

[sleepyjohn]

Blue, tile? roof would be a start, blue being the second coolest, keast heat absorbing colour next to white!

Actually I'm not sure that this thing about blue isn't wrong. The big heat radiation is at the red end of the spectrum. Therefore if you see the colour red it means this colour is being reflected. If you don't see it it's not.

You'd better not use blue any way because if you build another blue roof I will kill you.

I recommend, and have built abroad, high ceilings with insulated (pref polyurethane foam) layer beneath tiles, and pref also small ventilation gap situated above the insulation vented above and below, ie eaves and ridge..

Then inside the ceiling have air ingress below and egress at the peaks. You will in efect have ventilation INSIDE the roof structure and INSIDE the room.

You will need light up high....north facing skylight or side-peak-window....but will have a much bigger feeling room for your trouble.

You will not feel any heat at all.

[Lost in LOS]

I am a general contractor for 35 year in California and now the last 2 years Hawaii, retiring to LOS in May.

I am not sure of all the materials available there but some suggestions I can give you

concrete tiles, light color to reflect heat

attic insulation fiberglass great thicker the better [in L.A. it is R-30 10.5" thick] not squashed together but loose. the air trapped is the key. if no room than 4" foam under the roof tiles which is just as good but more expensive

large attic space well ventilated

high ceilings

ceiling fans throughout

a whole house exhaust fan unit ventilated to exterior

if a plywood is used on the roof under the tile there is one with a sheet of foil under it that will reflect most of the heat, if not available then you can buy a roll of this inexpensively an install it under the roofing material and it will reflect most of your heat. put it on my house in Hawaii and checked with a infrared gun. where the foil was to where it was not was 15 degrees different

feel free to pm me with any questions

Jimmy

[Beachcomber]

Thanks for all replies and will follow up the suggested leads.

Ventilation in the roof space I had thought of and insulating material beneath the tiles sounds good idea. And is that right not to insulate the ceiling so as to let the heat from the room pass through?

Having lots of plants and tall trees will also help but these take time to grow and would have to figure where to plant them to optimize the shade.

So which is better Red or Blue tiles? I would guess the plain cement light colored ones would reflect the most but they don’t look good. Personally I prefer blue, sorry SLEEPYJOHN it won’t be near Chiangmai.

The water sprinklers on the roof I saw were all on open shops or restaurant where AC would not be practical. The water mist system works I seem to remember they used something like that at the OZ Olympics.

Guess the next stage would be to somehow work out if the old house would take the weight of a cement tile roof. At the moment it is corrugated tin.

[sleepyjohn]

Guess the next stage would be to somehow work out if the old house would take the weight of a cement tile roof. At the moment it is corrugated tin.

It will not take the weight.

Cement tiles are three times as heavy as slate, and if a slate roof in UK is replaced with tiles it must be heavily reinforced. The slate itself is already going to be massively heavier than your tin sheets.

Take my word for this I have personally re-slated my girlfriend's cement tile roof that started gaping open between the tiles as the rafters sagged.

There may be a way round this that will save you a lot of money and effort and look better:

I personally think corrugated pressed cement sheet, the one that looks like asbestos, green or dull red but NOT blue can do very well indeed. The problem is usually it has no edgeing here and therefore looks cheap and nasty. Put a gutter around it and nice ridge and saddle mouldings, and it looks good, much better than cement tiles to my mind. Somewhat neo-colonial from the 50s. Also low cost and no heat retention as less massive. Not quite as light as tin but not far off you may get away with a little extra propping in the framework, like a purlin (easy) or even nothing.

[sbkpeterpan]

There is a company in Bangkok manufacturing insulated long run steel roofing, unfortuntaly I cannot locate their location but they do have a website. From Memory, its painted steel formed sheets with an insulating material sandwiched between each sheet, it would be very rigid saving on support structure as well as an excellent insulator.

[sbkpeterpan]

Just found their details, although their website is not working.

P.U. METAL SHEET CO., LTD.

Address:

80/54-55 Moo 20

Soi Triump Center,

Teparak Rd.,

Bangpliyai, Bangpli, Samutprakarn

Thailand 10540

Telephone:

027304880

Fax:

027304880

Email:

[email protected]

URL:

www.pumetalsheet.co.th

[Beachcomber]

Thanks SLEEPYJOHN the corrugated cement sheet seems like a good solution. Since this all came up I have been taking more notice of roofs and have seen those sheets finished with cement edgings that did not look too bad.

SBKPETERPAN - the insulated sheet steel sounds promising as combined solution solver. I will follow up the link and try get a picture to see what the finished look will be.

We plan to go visit up-country, where the house is, in the next month or so, and I’ll take more notice of the roof structure details. Wasn’t relevant last time.

Beachcomber

[phibunmike]

The water sprinklers on the roof I saw were all on open shops or restaurant where AC would not be practical. The water mist system works I seem to remember they used something like that at the OZ Olympics.

Sprinklers on the roof work, but I think are really only for existing galvanised rooves - not a design idea.

Be careful with misters - if you don't run them every day, you have a great bacteria farm complete with aerosol dispensing system, excellent way to get everyone sick.