Sorry, first link didn't work, it's five ways to heatproof a 50c city" and talks about different methods.

Duncan wrote: ↑Wed Jul 24, 2019 7:30 am What is the temperature of the ceiling inside the apartment. ?

I think sheets of polystyrene would work, but you may have to glue or weight them down so a wind will not suck them up and blow them away.

Ceiling temperature is about 2 degrees hotter than counter top level. I thought it would have been more but it was only slightly higher.

The room was 31 degrees this morning, at 7am, and after the AC was off for 7 hours (only getting it down to 29c by 12pm!) The outside temperature at 7am was 26.9c So, either this room is super insulated or the the roof structure is retaining so much heat it makes internal overnight cooling impossible.

The room is 4m x 6m. The BTU calculation is 6500 and the AC unit is a 1,5HP 12000BTU unit so there should be no issue there.

The other day, when it was mostly overcast, the room could be cooled to about 26c. However, yesterday when it was sunny almost all day I could not get the room temp below 29c. Yesterday the roof suface temp went up to 56c.

As for fixing, I was going to use some strong resin type glue and affix 2' batons to the ceing and then the poly tiles over them, thus creating a gap underneath to allow water to leave the roof in the normal way. If this works a more permanent solution will be sought but in the meantime this is just an experiment.

Sorry for long winded reply...

Some glues will desolved polystyrene so check with a sample first. I painted the roof tiles of my place with a cheap white paint and it certainly lowered the temperature.

Duncan is quite right about some/many glues dissolving polystyrene. And about painting your roof (and house) white.

Sorry to be a nay-sayer, but unless you think fire safety and good building regulation should only apply to Chinese developers - DO NOT use polystyrene for this purpose. A very bad idea.

Go look it up - i thought everybody would already know this.

Duncan wrote: ↑Wed Jul 24, 2019 8:09 am
..... I painted the roof tiles...

Gee Dunc, this photo shows you to be a lot younger and fitter than i imagined.

SternAAlbifrons wrote: ↑Wed Jul 24, 2019 8:36 am

Duncan wrote: ↑Wed Jul 24, 2019 8:09 am
..... I painted the roof tiles...

Gee Dunc, this photo shows you to be a lot younger and fitter than i imagined.

No, when I looked down from the fourth floor I realized I couldn't hold onto my walking stick , the paint and the brush all at the same time, so I got my twin brothers second cousin to paint the parts closest to the edge.

Duncan wrote: ↑Wed Jul 24, 2019 8:09 am Some glues will desolved polystyrene so check with a sample first. I painted the roof tiles of my place with a cheap white paint and it certainly lowered the temperature.

I was thinking about white paint as a heat reflective colour but wondered just how effective it was. The current colour is dark reddish black.

AndyKK wrote: ↑Tue Jul 23, 2019 5:49 pm

Barang_doa_slae wrote: ↑Tue Jul 23, 2019 4:08 pm I bought some in the cardboard boxes shop near Olympic stadium on upper Sihanouk close to the big Canadia branch.

Yes that would be the place too look, I have not looked in Phnom Penh personally, but there was plenty in battambang at around that type of thickness you are wanting. And about a meter long by half wide, some bigger. Not that I need any just now for myself, but Doc67, if you go and buy some would you be kind to post back on size and price please? Thanking you very kindly.

Polystyrene is available at the packaging store about 5 shops along from Canadia Bank on Sihanoukville. They have lots of home made cool boxes outside, you cant miss is. Poly' is available in thin sheets right up to 50mm thick.

For 1000mm x 500mm x 50mm (so 0.5 of a square metre) is 9000 riel. It was 10,000 but she offered a discount. I suspect that is the barang price and have not tested it with a Khmer friend asking for a price. So, it's about $4.5 per square metre and I need 25 of them so $100 or so. Plus glue.

As all around me thinks sticking polystyrene on the roof tiles is a bad idea, I will look at the white paint option. But I still can't see the fire risk of having a layer of the stuff on the roof. If it gets hit by lightening there will probably be rain around at the time to put it out. To be honest, I am more worried about the guy downstairs who fires up his indoor bbq once a week.

Doc67 wrote: ↑Wed Jul 24, 2019 12:19 pm

Duncan wrote: ↑Wed Jul 24, 2019 8:09 am Some glues will desolved polystyrene so check with a sample first. I painted the roof tiles of my place with a cheap white paint and it certainly lowered the temperature.

I was thinking about white paint as a heat reflective colour but wondered just how effective it was. The current colour is dark reddish black.

Doc67 is that part of the roof accessible. For dinning, or even a small garden and so on. I would utilise the area if possible, and put up a steel framework with tin sheeting above. Yes the sheets get hot but it will keep the part under there, that you want cool.

Thank you so much for the information on the polystyrene product.

AndyKK wrote: ↑Wed Jul 24, 2019 2:07 pm

Doc67 wrote: ↑Wed Jul 24, 2019 12:19 pm

Duncan wrote: ↑Wed Jul 24, 2019 8:09 am Some glues will desolved polystyrene so check with a sample first. I painted the roof tiles of my place with a cheap white paint and it certainly lowered the temperature.

I was thinking about white paint as a heat reflective colour but wondered just how effective it was. The current colour is dark reddish black.

Doc67 is that part of the roof accessible. For dinning, or even a small garden and so on. I would utilise the area if possible, and put up a steel framework with tin sheeting above. Yes the sheets get hot but it will keep the part under there, that you want cool.

Thank you so much for the information on the polystyrene product.

It is accessible, sort of, via a steep narrow metal framed staircase, through a red hot metal flap door in the roof and then over a concrete disused water tank (foreground) of the picture which would need demolishing and removing. I am thinking of white paint and then, if needed poly tiles.

I still can't see how a few poly tiles on a tiled roof poses a fire hazard to me below. If the building catches fire and it spreads all the way to the roof then I reckon I have bigger problems than the poly tiles caching alight. But I am willing to listen...