Spring is here and my home office is already getting uncomfortably warm. The office has a sloped, south-facing, concrete-tiled roof. I'm pretty sure that it overheats on sunny days largely because the black tiles absorb lots of sunlight and the insulation in the ~100mm gap between the tiles and the plasterboard isn't great. In a year or two I'll rip down the plasterboard ceiling and install some decent insulation up there. But in the mean while, I'm wondering if I can simply climb onto the roof directly above the office and paint it with a white gloss to reflect as much sunlight as possible?

Are there any legal or structural issues I need to worry about? The study's roof is not visible from the street. The only people who can see the roof are my direct neighbours and of course I'll discuss my plans before I start any work. Will the paint prevent the tiles from breathing sufficiently? (do concrete tiles need to breath?!) Any recommendations on which paint I should use? (might this be a good opportunity to try some "insulation" paint with high emissivity?).

If I wanted to paint my entire roof white, would I need to get planning consent?

Cover it in tin foil, shiny side out. If it becomes an issue with someone then it is easy to remove. And then insulate, insulate, insulate.

Tony

Posted By: tonyHow much heat do you have to throw at it in winter?

Probably the same amount that has to be expelled in summer

Have you not got eave vents and ridge vents? on the roof. I fear painting "concrete" tiles will lead to tears as moss forms in the crevices in winter and the sanded face of the tiles falls off. I like the idea of tin foil but I am doubtful if you can fix it on without the winter gales ripping bits of it off.
Frank

Thanks for all the replies!

I would love to insulate it now but that just isn't practical unfortunately; we're planning to renovate the upstairs in a year or two so I'd prefer to do the insulation then. The room isn't heated much in winter to be honest; I just put on more jumpers.

How would you suggest I attach the silver foil to the tiles? The only secure yet removable way I can think of is to take each tile off, one by one, and wrap the foil round the tile. But that sounds rather labour intensive. Any other ideas?

Yeah, I hear it's considered bad manners to kill strangers ;)

Not for ply, surely. I'd be worried about the surface of the conc tiles. Some 'sand out', so you'd be sticking to nothing solid.

So it sounds like the most durable, safe and reversible solution is something like:

* remove each tile one-by-one
* apply some contact adhesive to the tile
* wrap the tile in silver foil push the foil into the adhesive
* replace the tile

Does that sound about right?

If the foil blows away in the wind then it wont cause too much damage, unlikely large sheets of ply. Plus the silver foil shouldn't rot.

Then if the neighbours complain you can always remove the silver foil, especially if you use the contact adhesive on the back of the tile.

I'd be worried silver foil would rip too easily. Are there any cost-effective laminates where two thin plastic sheets sandwich a silver layer? The only such products I've found are expensive and too thick. Or maybe it's best just to use white plastic sheeting rather than silver (not quite as reflective as silver but a lot better than black tiles).

As it apparently doesn't matter that the roof's appearance is changed, how about overcladding with corrugated iron? No, I'm serious, great stuff.

Having thought about it for a while now I could suggest a large white tarpaulin held down with old planks?

If it were mine I would take off the top row of tiles cut a hole on the sarking and fill the voids with polystyrene beads.

Finally got around to it: Up to 23 C less temp by using tin foil today. It all goes into the shade at about 12:30PM

And your digital radio will stop working! There are others on here that can help with the conspiracies I am sure.

I intend to paint them and see what happens. I was amazed by the difference in this relatively lower power application.

More to follow in time.

Decor8uk

Any chance of a sample so I can try it out?

Mark

The 23 C (ish) is a peak temperature, not had a chance to fully analyse the data yet but I will. Apart from the the radiation and external temperature the two tiles (or the void beneath them) fit in with Newtons Law of Cooling. I agree that the best way is to shade, but this can be a bit tricky on a roof of a house.

I am going to do a few more tests to see where it leads, in fact I am just off to get some more tiles and insulation now to make a better test rig up. More to follow.

Steamy Tea ,

We have a rig made up with a heat lamp heating two "mock up buildings" one tile is coated with BLACK ClimateCooler the other coated with a reputable BLACK roof tile coating.
Black is obviously the biggest conducter of heat so if it was coated another colour the heat refelectancy would be even greater!
We have thermometers inside each "building" and after an hour the inside tempersture of ClimateCooler reads 28 deg C the non ClimateCooler reads 43deg C !!
You could put your hands on the ClimateCooler tile but the standard coated tile is too hot to touch!

A case study has been done at "The Clarion Hotel" Copenahgen . They expect the project to have paid for itself in 2 years due to cooling savings in their air con ! Their roof was 5500m2 and will reduce their CO2 emissions by 27 tonnes year on year - the equivalent of driving 105,000 miles in a car!!

It costs 5 times more to cool a building than to heat one!

I can forward you a copy if you would like?