Flat Roof

rafraf03

Hey Guys!

I am having a second viewing tonight of a property that has an extension with a flat roof.

What should I be looking for to detect any likely problems?

Any help is much appreciated!

courtjester

There's probably little you can do to detect a problem - flat roofs can be fine one day and fail the next without warning.

It would be useful to know when the roof was last renewed - life expectancy is 15-20 years generally if they are well constructed.

Should be well covered with loose chippings with no water pooling and preferably free of moss, although the latter is quite common on roofs more than 5 years old so is not an indicator of a problem.

If there is any debris (such as broken tiles or slates) lying on the roof, this could be a sign of damage or potential splits in the felt.

Has the ceiling of the room directly under the roof been recently repainted?

BargainJunky

My mum recently bought a bungalow with a flat roofed garage. On the survey the surveyor pointed out that flat roofs have a limited life span etc etc and that some minor repairs had been carried out to the edge.

She completed her purchase on 1st Dec and on 18th Jan during gale force winds her roof and her neighbours left the garage and ended up in the garden!
The roofer that came out to inspect the roof said that it had been nailed on and not bonded hence a very good gale and the whole lot blew off. Now trying to claim off the insurance company - o wot fun.

rafraf03

Hi Courtjester,

Thanks for the reply.
I know this is a long shot, but what sort of state the surface of the roof should be in if it is say 5 years old, 10 years old ?

Sorry about my ignorance but I know nothing about flat roofs ...

rafraf03

Thanks For your story BargainJunky.

the seller is himself a builder, Hopefully the roof has been built to good standard.
But because you can never be too cautious ...

courtjester

Difficult to generalise - 5-10 years old it should still look 'newish'. Common sense will probably flag up whether the roof looks OK or not to you - obviously watch out for any evident repairs or patches or visible cracks.

An old roof will probably be blackened or heavily covered in moss.

These types of roof don't tend to deteriorate gradually, they last until they fail, so you almost certainly won't glean much information about its condition unless its obviously clapped out.

Unless it is a very large roof area, I wouldn't be over-concerned. Cost to replace would be £500-£1000 for most typical extensions, probably less if there is no significant internal water penetration.

prudryden

Find out if it is only felt - or if it is properly asphalted, which is the more expensive but correct way. Asphalt will last a very long time, especially if it has also been coated with heat reflective paint.

fbrj

courtjester wrote:

It would be useful to know when the roof was last renewed - life expectancy is 15-20 years generally if they are well constructed.

I think this is a little optimistic. I have always understood that you should assume 10yrs life and anything extra is a bonus! Anecdotal evidence (my own and friends) would support this. In our own case, we replaced a flat roof on an extension of a house we bought in 1990. It was replaced in 2003 at a cost of about £2500 - the roof area is about 35ftx25ft.

Check carefully in the rooms(s) under the extension for signs of leaks/water damage/repair. Maybe just ask - you never know, it may have been replaced quite recently and still have some guarentee left on it!

ukmike

prudryden wrote:

Find out if it is only felt - or if it is properly asphalted, which is the more expensive but correct way. Asphalt will last a very long time, especially if it has also been coated with heat reflective paint.

Correct! Had an asphalt one on a previous house that was still going strong after 60 years,but the 10 year old felt one had to be replaced.

dadrock

If its got loose chippings on it then its probably at the older end of the scale. These days its normal to coat the surface with a reflective paint to protect from heat.

poodledoodledoo

I have just purchased a property with a flat roof and what you really need to look out for is basically any signs of the roof sagging or damp patches on your walls. The average flat roof will last for about 10-12 years. The cost of replacing the roof covering on a whole house is only £1500ish mind you so if there are any problems with your extension, they shouldn't be too problematic or costly to resolve.