What time of year should I build a roof terrace?

What time of year should I build a roof terrace?

Lisa Andrews (Horticulturalist) gives expert video advice on: Do I need an architect to design a roof terrace?; Do I need a structural engineer for a roof terrace?; Should I hire a specialist roof terrace constructor? and more...

Given today's climate, we can build roof terraces all year round, except when the temperature drops to under five degrees Celsius. This applies for any exterior building work and also would not be the optimum time for planting.