Flat roof as percentage of roof area.

[Christy]

Hi

I am getting finance to undertake house renovations. The mortgage co won't lend on a house that has more than 25% of flat roof space

The house has a dormer set into the tiled roof. I calculated the total roof area and then the dormer roof area.

Subtracted the dormer area from total roof area which means less than 25%

However a friend has said I need to calculate the actual tiled roof area and then subtract the dormer roof area. 

In which case it is over 25% flat roof. Does anyone know the calculation method valuation surveyors would use?

Thanks

[PeterW]

Are you measuring areas on plan ..? You need to measure the actual area of sloping roof, then subtract the flat area 

[Christy]

Thanks

Have measured the actual sloping roof area not off a  plan