flat roof vs pitch question - townhouse

Hi All,
I'm about to purchase a townhouse but after looking at the design. It is going to have a flat roof and i'm a bit concern.
I have read that pitch roof have less problems that flat roof.
My question is :-
- Do flat roof get hotter in summer
- Is it more expensive to maintain
- About maintenance - for example when there is a leakage
- Does it leak more than pitch roofs?

Thanks in advance

 

A roof can only be two of:

• Flat
• Reasonably priced
• Long term leak free

 

What is the roof made of, and are there any box gutters?

 

Thanks for you response.
Can please clarify in details

 

Thanks Hamish for you response.
Will get more info and let you know

 

Flat roof has a few issues:
- lower pitch means water running off slower. If heavy rain, you might have a problem.
- If the area is large or long, it might slightly sag in the middle over time. That might collect water and attract moisture. I have a case which led to termite infestation due to humidity.

 

A good sloping roof will generally last forty of fifty years without significant problems.
A 'Budget' flat roof (that a builder of a typical town house provides) will be lucky to last 10-15 years before leaks occur. When they do repairs are much more difficult and expensive to repair than a sloping roof.
A flat roof that would be provided to a multistorey building is likely to be expensive but more resistant to leaks and easier to repair than the budget flat roof. (In a multi storey building the cost of the roof is a smaller %age of the total build cost so there is less pressure for a budget solution)

 

When you say flat do you mean skillion?

 

Thanks all for the responses.
I have attached the plans and after looking at it . It seems its a pitch.
Please confirm its not a flat roof

 

Thanks Wylie so is it ok or vey bad?

 

Are we talking about the garage area roof? It's quite a standard set up and is the type of roof most people perceive as flat. All "flat" roofs need to have a small degree of pitch to run water to the gutter system. To deal with the lower pitch the roof sheeting will generally be something like trimdeck instead of custom orb so that it can drain water more efficiently.

In this case its a low pitch going towards a box gutter. Box gutters can be more prone to leaks but that is generally just something to be aware of and monitor - I wouldn't not buy something because it has a box gutter.

 

Snow? Worry much more about hail. The pitch at 2 degrees is the absolute minimum possible and with box gutters a decent hail storm will see the gutters blocked and water ingress. Also, keep those box gutters really clear of leaves etc. or heavy rain will lead to the same outcome.

Oops - only looked at the first image with the 2 deg slope and box gutters over the patio - still a problem but far less serious.

 

Have you considered getting a building inspector to assess it for you?

 

A flat roof will usually have minimal pitch for drainage and it wont be flat unless its a pergol / small area eg carport and then be barely noticeable at 3%. Its often achieved with a false exterior with a fall behind it. (Pic below) Its the invisible. It looks flatter than it is. Roof manufacturers seem to condition their warranty to stop a flat roof as this can be prone to leakage or deluge issues...and claims.

And then I found the Stramit guide .... Pitch will vary with the materials roof size and regional location of property to cope with rainfall and deluge. Makes sense I guess.
https://www.stramit.com.au/assets/Technical-Resource-Documents/Stramit-Roof-Slope-Design-Guide.pdf

In pic note how the flat roof on the left ...isnt. The roof on the right is concealed inside the edging and likely has similar fall