Looking At Buying A Flat Roof House

[jameshudson45]

I am looking at a house for sale that has a flat top roof. I don't know anything about these types so that is my biggest hesitation for this purchase. I haven't been up there yet so I don't know what it looks like or where the water goes or anything like that. I can't even tell if this kind of house has an attic? It looks like if it did, it wouldn't be large enough to even move around.

Can you tell anything by these pictures? Is the roof even with the top of the shingle line or is it recessed a couple feet or what.

I will have the hosue inspected before buying, but should I have a roofer look at it too? Anything else I should look at for these types of roofs?

Thanks

[johng]

You forgot the pictures................

[Crossy]

You forgot the pictures................

As a Noob he can't upload attachments until he has 5 posts (IIRC).

[hanno]

I have yet to come a cross a flat-roofed house that is 100% water tight. I worked in a hotel and we tried everything but every time one of these massive tropical downpours came along, the bl**dy thing sprang leaks everywhere.

[Rimmer]

My old dad used to say it is impossible to make a flat roof waterproof, my present collection of flat roofs confirm what he said was right.

[teacup]

Most flat roofs are torched down with asphalt over the waterproof membrance. The odd of leakage really depends on the workmanship of seams torching.

And

There is NO such thing as "flat roof". Even if you see them as "flat" by naked eyes, but in fact they actually have some slope of a minimum: 1 inch per 10 ft normally.

[mossrisjhons]

Please Show pictures

Edited May 19, 2009 by mossrisjhons

[mossrisjhons]

absolutely yes

[hanno]

but in fact they actually have some slope of a minimum: 1 inch per 10 ft normally

True, but it is probably not enough to withstand the rains here. And as for craftsmanship: unlikely to find that here in SE Asia.

[teacup]

but in fact they actually have some slope of a minimum: 1 inch per 10 ft normally

True, but it is probably not enough to withstand the rains here. And as for craftsmanship: unlikely to find that here in SE Asia.

Well anything more than that, it wouldn't be called a "flat roof" anymore, it will be a low slope "shed roof"

Agreed tho...about the quality of craftmanship here.

But if you arm yourself with some technical knowledge beforehand, you can at least inspect it yourself and tell them to fix any deficiencies right on the spot/ or later….at your satisfaction.

It’s not like the OP is buying a palace or something here, so it’s just going to take the OP less than 30 mins to walk back and forth across the roof.

[Rimmer]

It just rained again this morning and my guest room deck (roof over the gym) is flooded again, the tiled deck (roof) slopes all right!! Toward the two sliding glass doors where they pool nicely and run down the inside walls of the gym underneath instead of the other way which would shoot the water off on to the pathway below through the open balustrades.

[tjo o tjim]

Flat roofs are really a pain. Even for commercial buildings with expensive systems it is impossible to have a perfect roof. If the drains stop up at all (or are overloaded) then pressure builds and the roof doesn't stand a chance. It isn't the right solution for the tropics.

[Artisi]

Flat roof - WHY?

[lopburi3]

One solution for leaking flat roof that we tried some 35 years ago was to cover it with boat making fiberglass. That did stop the leaks; but have no idea how long it lasted.

[Rimmer]

Hopefully the OP will have the message about flat roofs now

[dogleg]

Look from above you will see most shop houses with flat roofs have had sloping roofs built above to waterproof and keep off direct sunlight.

[IraqRon]

You could turn it into a "green roof" which is becoming popular in many countries. Basically, you are putting a mat down, dirt on top of that and growing appropriate plants on the roof. It reduces the heat gain thru the roof, attacts birds, butterflys etc, captures rain water, and gives you a place to garden or have a small gazebo, etc. for the cool season. Of course your structure must support the added weight.

Google it and you will find lots of info.

When given lemons, make lemonade, or limes most likely in Thai.

[lopburi3]

And when you add a foot of water (only a few minutes rain here) it is a considerable extra weight.

[FarangRed]

I am looking at a house for sale that has a flat top roof. I don't know anything about these types so that is my biggest hesitation for this purchase. I haven't been up there yet so I don't know what it looks like or where the water goes or anything like that. I can't even tell if this kind of house has an attic? It looks like if it did, it wouldn't be large enough to even move around.

Can you tell anything by these pictures? Is the roof even with the top of the shingle line or is it recessed a couple feet or what.

I will have the hosue inspected before buying, but should I have a roofer look at it too? Anything else I should look at for these types of roofs?

Thanks

When you look inside the house, look for any visible signs first ie, repairs or re painting, the biggest problem I have seen here in Thailand with flat roofs is they get all the levels wrong and no drain off points so when all the leaves followed by heavy rain it don't take long to get blocked up and unfortunately water finds it's own level.

So as fast as the rain comes down it needs to be draining off and look to see if there are big trees over hanging.

I have also seen roofing felt being used too many joints and black colour which absorbs the heat and then cracks after a couple of years.

Also check against the perimeter wall and the roof joint, is that sealed that area will open up due to expansion.

I suppose if you do go ahead and buy the property, is to have the roof redone with a good concrete screed and make sure it's got water proofing in the concrete and then you can get all the levels correct and maybe put extra drain off points in.

Use the concrete that the swimming pool builders buy it cost a bit more.

Good Luck

[Artisi]

"----------------- the biggest problem I have seen here in Thailand with flat roofs is they get all the levels wrong and no drain off points so when all the leaves followed by heavy rain it don't take long to get blocked up and unfortunately water finds it's own level."

And the drainage point is always at the highest point of whatever you are attempting to drain.

[Rimmer]

It's not so much the flatness of the roof that is the problem but the edges where the roof joins the walls and water can pool. And as already pointed out any drain will always be in the wrong place.

The edges of the roof need to have a 'water stop' around any roof to wall joints or preferably the roof membrane (if fitted) should be carried up the wall for two or three inches. A 'water stop' is similar to the item used in swimming pools but this is seldom or never fitted.

The problem is that a flat roof will creep and shrink with building movement and temperature changes opening a gap between the roof and the adjacent wall holding it up for the water to run down any wall underneath.

Edited May 24, 2009 by Rimmer

[juehoe]

I am looking at a house for sale that has a flat top roof. I don't know anything about these types so that is my biggest hesitation for this purchase. [...]

Dear jameshudson45

Another issues is that houses with flat (concrete) roof will get very hot. So you should shade it (covered roof terrace).