[OShellszz]

Inside my house. The roof is flat, and it gets hot as hell, I want to fix this issue. The roof was once coated with some white coating, but that has degraded, and it's expensive to replace that coating every 2 years, I want a more permanent solution, has anyone had this issue and resolved it?

[Khcyhshq]

Inside my house. The roof is flat, and it gets hot as hell, I want to fix this issue. The roof was once coated with some white coating, but that has degraded, and it's expensive to replace that coating every 2 years, I want a more permanent solution, has anyone had this issue and resolved it?

We had a little bit of a problem like that with a home we purchased back in 2003, where the temperature was a killer and maintenance of the roof's elasto seal covering too much of a hassle.

We tried a friend's recommendation for the same problem which he also faced long ago. We used "gravilla" or fine gravel to place a thin coat all atop the flat roof and wet the roof once in a while during the worst summer heat waves. It worked!

We also found by trial and error, that using some weed killer added to the water also worked wonders to control unwanted greens growing there.


A word of recommendation after using three types of gravillas: Buy the one that's white in color, the lighter the better!

[fuesquemill]

dipre; You could use rigid foam insulation panels 6" by 4x8 and your roofing could go over it, it will give you good insulation for the money.

[q9h9pPne]

Ditch the flat roof, it will be a problem.
I've never seen a flat roof here that didn't eventually leak;
and they invite heat, contraction and expansion.
No need to rip it off, just cover it with a sloped style.
Corrugated metal, cana, whatever.
Open to suggestions.

[OShellszz]

We had a little bit of a problem like that with a home we purchased back in 2003, where the temperature was a killer and maintenance of the roof's elasto seal covering too much of a hassle.

We tried a friend's recommendation for the same problem which he also faced long ago. We used "gravilla" or fine gravel to place a thin coat all atop the flat roof and wet the roof once in a while during the worst summer heat waves. It worked!

We also found by trial and error, that using some weed killer added to the water also worked wonders to control unwanted greens growing there.


A word of recommendation after using three types of gravillas: Buy the one that's white in color, the lighter the better!

This is a good idea, but I'd like to keep the roof from getting wet at all if I could help it.

dipre; You could use rigid foam insulation panels 6" by 4x8 and your roofing could go over it, it will give you good insulation for the money.

The house has already been built and finished.

Ditch the flat roof, it will be a problem.
I've never seen a flat roof here that didn't eventually leak;
and they invite heat, contraction and expansion.
No need to rip it off, just cover it with a sloped style.
Corrugated metal, cana, whatever.
Open to suggestions.

This is what I was thinking of doing, I'd build the new roof about 6" above the old one, that way air could get in between the layers and keep the actual roof cool.

[pedFlicle]

This is a good idea, but I'd like to keep the roof from getting wet at all if I could help it. What do you do when it rains?

[soprofaxel]

This is a good idea, but I'd like to keep the roof from getting wet at all if I could help it.

The house has already been built and finished.


This is what I was thinking of doing, I'd build the new roof about 6" above the old one, that way air could get in between the layers and keep the actual roof cool.

Common sense dictates it should be a lot cooler, but I think I'd go with 8" instead of 6" and make sure they run parallel to the wind direction.

[moopogyOvenny]

Our house here will be build with a flat roof (slightly tilted of course to drain water) but the ceiling height will be almost 4 M, roofs will be covered with white gravel or what's available here and the house will be build in the direction so that the sea wind will always blow through the house. All rooms with large windows and not sure of this yet, either the windows will have sliding wooden sun protectors or the roof will be acting as sun protection by building it over the edge of the walls or maybe the two, don't know yet.

The houses I designed in Belgium were all flat roofs and covered with white gravel but then against the cold, act as a very good isolator.

Acira

[fuesquemill]

Dipre: If the house is already built and finished, you could.. if..you have room from the inside, attach the rigid insulation from the inside. It will make a great deal of difference to your inside temperature.

[Khcyhshq]

Gravilla is the way to go, since adding anything atop the roof will be asking for a sure to come problem when storms come about, pests, mold, thieves, etc...

What do you think they use in large commercial roofs with concrete?

You can leave a small channel (gap line) in some sections that follow the designed concrete's slab drain pattern, in order to have excess water removed when it rains to avoid leaks due to filtration.

The gravilla acts as a natural insulator for the home, both for the cold and hot temperatures. It limits the exchange of the air inside and outside via thermal transfer by trapping air in bubbles that act like mini insulators. When the day time is very hot, the white gravilla reflects most of the solar heat away, and what's left of it after the sun goes down will act as coolers when the gravilla damp their surface due to the cooler air.

Like I said (and is done in commercial roofs) you can wet the roof when it's very hot to create a rapid exchange of temperature from the gravilla and cool the house even more during the hot streaks.

It's highly recommended to AVOID building a new roof line above a concrete slab, because the normal heat exchange is disrupted and will cause mold and other problems to the concrete roof.

Mold accelerates the decay of the salt-oxides in the concrete and also can infiltrate the pores all the way inside the house.

[Khcyhshq]

The above is cheap gravel, but not as effective as the whiter type (Quartz).

You want the whiter kind, which will reflect most of the Sun heat away from the roof and retain lesser heat to condense during the night as the gravel dampens due to the cooler air.



The smaller the pebbles the better! The heat gets less retained and dissipates faster during the nights cool down.

And let me tell you: This is a one in a time investment that needs NO maintenance or upkeep at all, just using some bleach on the water once in a while will keep them white and free of mold/green stuff, or best weedkiller...

And the best part is that you can do it yourself, with a minor help to place the sacks on the roof...

[OShellszz]

The gravel seems like a good idea, and it's much cheaper than what I had in mind, but what about when it rains, and it's been raining a lot lately, wont the water get stuck between the pebbles and damage the roof?

[Khcyhshq]

The gravel seems like a good idea, and it's much cheaper than what I had in mind, but what about when it rains, and it's been raining a lot lately, wont the water get stuck between the pebbles and damage the roof?

Nope! Water will continue to drain as before, but a minimum will remain on the pebbles below the layers. They form bubbles(air pockets) with the heat, which in turn produce a normal insulation layer for the concrete slab.

In fact the layers of gravel will extend the life of the concrete by much more than how it's exposed to the elements now.

[pedFlicle]

The gravel seems like a good idea, and it's much cheaper than what I had in mind, but what about when it rains, and it's been raining a lot lately, wont the water get stuck between the pebbles and damage the roof?

Gravel is used for drainage precisely because water will not "get stuck" between the small stones.

[OShellszz]

Ok, what I will do is, add a thin layer of white cement to the roof, and then throw in a ton or two of white gravel. This will be much cheaper than all the other options.

[pedFlicle]

Ok, what I will do is, add a thin layer of white cement to the roof, and then throw in a ton or two of white gravel. This will be much cheaper than all the other options.

What's the purpose of the thin layer of cement? You would need to prepare the surface of what you have now and use a bonding agent as well. For the cost and effort what's the benefit?

[pedFlicle]

This is loose gravel that PICHARDO is recommending. Not stones set in cement.

[moopogyOvenny]

Loose gravel Dipre...

[OShellszz]

I know, but I want to resurface the roof as well, since it's starting to infiltrate.

I'll have the roof resurfaced with white cement, and after it dries, I'll put white gravel above it.

[pedFlicle]

I know, but I want to resurface the roof as well, since it's starting to infiltrate.

I'll have the roof resurfaced with white cement, and after it dries, I'll put white gravel above it.

Be careful with this resurfacing. You need to remove anything loose, apply a good bonding agent and use an appropriate thickness for the bed. Otherwise you'll end up with flaking and a bigger mess than what you've got now.