Would like to share the outcome of the installation, I used a double sided bubble radiant barrier and then 2 months ago installed a solar fan

Before:-
Plaster Ceiling :- 38.4c, Roof tiles:- 55C, air cond power :- 900-1000w.

With this I estimate attic temperature to be around 40-44c, going up to the room is like  a sauna..




After:- Radiant Barrier only
Plaster Ceiling :- 32-33c, Roof tiles:- 36-38C, air cond power :- 400-450W.
A radiant barrier really works, a must have. Made a huge difference in room temperature.
At the same time I started putting temperature sensor at my attic, external (outside my window) and my room to log the temperature.
I notice around 2c difference between external temperature and the attic temperature.


After:- Radiant Barrier + solar fan
Installed a solar fan so it would turn on roughly 8am to maybe 6- 6:30pm. Made a small difference, temperature now within 0.5c compared to external temperature.
Also integrated all in home assistant , to log the temperature and air cond power. Small savings in air cond power (maybe around 50w on average?)

Hi can you share more photo for the after installed bubble foil? Wanna know how you install the foil, whether is just take off the tile and lay on the wood, thanks

Look at post 7 for example

you put on top of the wood as i draw in the photo?
Because i cant see any other support under the tiles, if does not want to remove the tile and lay on

although roof tile with aluminum shield but feel no different, so better save money for aircond bills.

Look at blue arrow
staple radiant barrier to the blue arrow wood.
The thickness of the wood act as air gap.

Noted, can proceed with both
Radenshield to reflect most of the heat out back to roof tile, basically just stick on using construction adhesive to existing roof batten (the vertical battens in the A shape of the roof). In short, easy installation but ypu may want to do the add joists before the radenshield so easier for the installer to stick the radenshield on the rood batten coz to position a ladder or stool in there based on whats available now seems a bit dangerous, not much safe area for them to work with, risk of falling thru the ceiling is there.

Rockwool above plaster ceiling with additional wooden beam (flat joists) to support weight of people walking around, and between these flat joist you can just use flat bar or the alu batten same type as the plaster ceiling folks use, join them up between joists to look like a flat ladder to support the rockwool slab weight.

All the above is passive heat reduction method. Turbine also quite passive despite the monstrous size.
Active method involve boarding up your sides (ie close off your rooftop airspace to be only yours) so youre only cooling your rooftop airspace and not the whole row of 20 houses' airspace. By making a vent to be able to support the size of a ventilation exhaust fan or two unit ventilation fan about 10in KDK it is gonna move 400 to 500cfm so the air inside is not tupperwared long enough to bake (like now). The input you can just make a passive vent above the bathroom ceiling for it to have cold input air. Why i didnt wanna suggest 12in is that the hole is big and burglar can squeeze in. 10in should be small enough for them not to be able to drop in.

This active ventilation is like you park the car in the hot sun and opening all windows. The car cools better in minutes with the window open as compared to it fully rolled up. Even better if there is a fan blowing out all the time when it is baked in the sun. The exhaust fan you can use on timer so it only work on hot hours say 1100-2000hrs. The electric usage of an exhaust fan is very minimal compared to overworking your AC.

1st I choose for this tile side insulation. But later decide not.

As the insulation is too thin for effectiveness. It blocks the airflow between tile and traps the inner roof hot air from going out.

So I decide to DIY insulate the ceiling. Which is what I feel more directly affects me from the room side.

The ceiling is the most heat generate for the room as the ceiling sq ft is as big as the room floor.

Use the foam spray for the insulation. Brought a few box to try on my working room. Brought from shopee.







The foam expands about an inch thick. But if you want thicker, just spray another layer. The thicker, the more heat insulated. Spray some water before and after the foam. It help to expand the foam more.



It is a fast process and dry about 4-5hr. The next day, you are able to feel the difference.

Here is the result of the temperature difference inside the room without an aircon.





I can increase the aircon temperature to 29°C and it already feels cool. And maintain at 29°C for the whole day even it really hot outside. 

The left panel is the actual room temperature near the battery. (below the cabinet)  And the aircon remote temperature setting. I never get the same reading before that.



That saves my bill a lot when work from home.

1st I choose for this tile side insulation. But later decide not.

As the insulation is too thin for effectiveness. It blocks the airflow between tile and traps the inner roof hot air from going out.

So I decide to DIY insulate the ceiling. Which is what I feel more directly affects me from the room side.

The ceiling is the most heat generate for the room as the ceiling sq ft is as big as the room floor.

Use the foam spray for the insulation. Brought a few box to try on my working room. Brought from shopee.







The foam expands about an inch thick. But if you want thicker, just spray another layer. The thicker, the more heat insulated. Spray some water before and after the foam. It help to expand the foam more.



It is a fast process and dry about 4-5hr. The next day, you are able to feel the difference.

Here is the result of the temperature difference inside the room without an aircon.





I can increase the aircon temperature to 29°C and it already feels cool. And maintain at 29°C for the whole day even it really hot outside. 

hi, can we spray the polyurethane directly on the tile?

will the polyurethane disintegrate after few years?

The left panel is the actual room temperature near the battery. (below the cabinet)  And the aircon remote temperature setting. I never get the same reading before that.



That saves my bill a lot when work from home.

Hi, how is ur PU form now ? Does it disintegrate?
Did u mix it with something to reduce the flammable risk?

The foam doing fine. Room temperature still maintains good. Another good is, the rain noise reduce.

I didn't mix anything or do anything with flammable risk.

Brought more foam cans for the front room to insulate it. Haven't start yet.

If you worry for the fire risk, use rock wool. Easier to DIY.

Rock wool and glass wool are not in my mind yet as i dont want risk to the lung. 2 heavy smoker in the house. LoL.

Btw, do u have any suggestion for the side wall of the house than facing east, with sunlight exposure about 6-8hrs per day?
It is a rent house. I scare later landlord angry when we mod the prop.

I am thinking of the double aluminium foil with air bubble, stick to the tent shade and fix it with the long tall metal rod to block the sunlight.

The foam doing fine. Room temperature still maintains good. Another good is, the rain noise reduce.

I didn't mix anything or do anything with flammable risk.

Brought more foam cans for the front room to insulate it. Haven't start yet.

If you worry for the fire risk, use rock wool. Easier to DIY.