Concrete Flat-roof problems

Hi, our house used to be completely flat-roof but we've re-roofed most of it except for a small part (about 15 foot sq). It's about 6" thick concrete laid on top of boards & joists and of course being 6" thick we have had no problems with leaking into the house.

However, around the edges there's a lip of about 2-3" high of concrete designed to stop rain-water overflowing and guiding it down channels to the drain hole.

Water seems to be seeping in underneath these lips on one side and dripping down, not a major problem in itself but annoying and it leaves marks down the side of the house.

Have tried using some cold-applied bitumen coating from Wickes but that didn't seem to last at all.

Can anyone suggest any other sealants/coatings that might work better. I have considered having the roof coated with rubber or fibre-glass, Have considered Curon but does seem a bit OTT for what should be a minor fix.

Any advice greatly appreciated, also anyone with experience of Curon-seems to be a fairly new product?

Thanks.

Poddy

I have a sample of Curon here, stunk the office out for days lol.

I expect it works quite well though when it's cured does seem a little too thin in places.

I would suggest maybe a liquid coating product such as Sealoflex

more concrete.

I used fibreglass on my concrete box gutter, it worked really well. You can buy small amounts in most places too so it doesnt work out hugely expensive, would definately recommend it. Some websites offer help on how you do it too. It smells a bit but that dissapears after a while. I bought mine from a local company to where I live and they were really helpful, the guy is a mind of information as far a fibre glass goes