man on grass

Building a pergola will increase the living area of any home and can provide a valuable all-weather entertaining area. The main two choices are a flat roof pergola or a gable or pitched roof pergola.

A pitched pergola’s roof is attached to the house, a tall nearby wall or another standing structure and slopes downward towards the other end of the pergola, creating a single slope. This can be a little confusing because generally the term ‘pitched’ – when it’s used to describe a roof – means that it’s been built so that it slopes. But ‘pitched’ as it relates to pergolas means they’re attached to something. Pitched pergolas can come very close to being patios or verandahs.

Aside from this, the angle of roof slope is referred to as the roof pitch. In Australia we define the pitch in degrees. So a 5 degree pitch is pretty flat, and a 45 degree pitch is fairly steep. A standard roof pitch on a new build is usually 22 degrees but 25 degrees is often an option, but usually at a higher cost.

If you’d like your pergola to mirror your home’s pitch you will need to work out the length of your rafters. One recommended method is to use Pythagoras’ theorem. You will need to know the length of two sides of your triangle (in this case half of the width of your pergola, and the height of the ridge from the beam).

You don’t have to be Pythagoras to get it right.  

In mathematics, Pythagoras’ theorem, is a formula describing the geometry among the three sides of a right triangle. It states that the square of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides.

There are a number of resources that will help you calculate roof slope if you are building your own pergola, which will enable you to get the pitch just right and calculate the fall required for correct run off.

A popular site often recommended in renovation forums can be found at:

Block Layer

When designing a pitched pergola, you will need to take close stock of how the roof on your home is designed to cope with rainfall and drainage. You will want to make sure that any flow on from the roof has an adequate run off angle and that any run off flow can be directed.

This can be achieved by using guttering along the lowest end, or by slightly changing the angle of one side of the pitch to direct the water to flow off that side. You will also want to ensure that the pergola you intend to build complies with any applicable building regulations – something you’ll need to check with your local council.

The easiest way to ensure everything is done correctly is to get it built by Rite Price Roofing. Our company has been completing pergolas projects for more than 25 years in South Australia, and we are known for our functional designs, attention to aesthetics and great workmanship. You can sit back and watch your beautiful pergola being constructed without having to lift a finger!

Rite Price builds with the strength of Fielders steel.


When you choose Rite Price Roofing, you are also choosing to use only quality materials from the Fielders Centenary range. We partner with Fielders because they are an Australian company producing Australian steel in a huge choice of colours and finishes, backed by a platinum 25 year guarantee.

Steel pergolas don’t need painting, and you don’t get the warping, splitting or knot-filled beams you get with timber. Our high-gloss beams and posts offer a stylish appearance with very low maintenance. Your steel pergola can be engineered up to a height of 4 metres.

Our pitched roof design includes:

  • Great design versatility with large spans available.
  • Centenary Dek, Polycarbonate Hi-Rib or Corrugated Iron roofing or a combination of these.
  • A range of double sided and multi-colour roof choices to complement your home.
  • The ability to add Roman columns, blinds, vest ridges or different gable in-fill panels.

All of this makes the Fielders Centenary pitched roof unique in the industry. Rite Price Roofing provides you with personal service for the lot, from the design and approvals through to construction.

Call Rite Price Roofing Adelaide at (08) 8261 3941 for a free quote and solve the problem of building a pergola that is perfectly pitched for your property.