Curved Staircases for decks and mezzanines

Modern Curved Staircase gives a unique touch of class to any interior design, be this a private house or a commercial place. Here is our guide on how to build Modern Curved Stairs. Curved Staircases are often fitted in the atrium of houses or villas where there is a lot of space available and the curved or helical staircase becomes the central feature. In-house renovations and curved stairs for the deck or mezzanine can give a dramatic touch of style.

Due to the curved shape, there is a lot of engineering involved in the design of the helical staircase.

The number of steps is given by the floor-to-floor height (staircase elevation) you have. The minimum width of the staircase is generally 30’ (910 mm) but we can produce curved stairs for a deck up to 70’ or more (2130 mm).

Let’s start!

As there is no ceiling opening but a deck, we have no major issues with measures at the staircase exit. You only need to check the position where you want the top step to be.

Step 2. Number of steps

Now that you know where the staircase exit will be, you need to find out where the departure tread will be. There are different systems to determine this. The faster way is to allow for a fixed riser height and calculate how many risers (and steps) you need depending on the finished floor-to-floor you have.

Step 3. Floor to Floor measure. How to build modern curved stairs

If you have for example a finished floor-to-floor height of 10’ (3048 mm) you can go for 18 risers of 6  11/16’’ (170 mm) each. On domestic curved staircases, we usually have risers value going from 160 to 180 mm. A higher riser could make the staircase less comfortable when climbing up the stairs. However, you should check the allowed value with your local building officer or building codes. The value of risers and going have to be designed according to the stairs building regulations of your area.

The finished floor-to-floor measure is the vertical distance from the top of the finished lower floor to the top of the finished upper floor.

Step 4: Top landing platform

The top tread is generally designed as one riser below floor level and has the same measures as all other treads. In some cases, we can however design the top tread levelled with the floor and bigger than other treads. We call this landing platform.

Step 5: Draw the curved staircase plan – Curved or Helical Staircase Design Calculation

It is quite tricky to draw a curved staircase plan, the good news is that many online staircase calculators can help you.

Here below is an example of a design for a Curved  Staircase for the deck.

Staircase:  width 1000 mm, floor-to-floor height 3000 mm, 17 risers of 176 mm, 16 curved steps

Here is how the staircase will look in the curved staircase drawing:

The main rules for drawing an outdoor curved staircase for the deck are similar. There are generally no major impediments or walls, therefore you may be able to design a wide curved staircase to reach the deck.

Being the external staircase exposed to weather conditions you will need to pay attention that all the curved or helical staircase parts are properly treated and suitable for their use. The steel is hot galvanized, the stainless steel is the Aisi 316, and the wood parts are suitable for external use. For timber external staircases we recommend using wood types such as teak, iroko, or any other hardwood not sensitive to humidity, and cold and hot temperatures.

Step 6: Check Building Regulations on how to build modern curved stairs

Check that all measures are complying with the staircase building regulations in your area and you are done! Good Job!

For England and Scotland, you can download the complete regulations on the UK planning portal website.

Step 7: Curved Staircase styles and design

Depending on the style and design of the staircase you want to achieve, there are several materials we can use to produce the curved staircase and the curved staircase railing. The material choice is vast. If you want a Classic Staircase you can choose among different wood choices such as oak, beech, walnut, and others. If you prefer instead a Modern Staircase look, you can go for a combination of glass and painted steel or a stainless steel staircase. You may also want to lighten up your treads by adding LED lights.

The price of the curved staircase for the deck will vary depending on the material and also on the staircase engineering. A metal staircase will be the most cost-effective, whereas a glass spiral staircase will be the most expensive.