How to build stairs for a raised deck terrace?

In practice, two situations should be distinguished:

1. one step or a single level difference – can be executed using adjustable pedestals and the universal side finishing closure plate for the terrace,
2. two or more steps – we recommend constructing an independent, rigid substructure from the aluminum AluDeck system.

This distinction is very important.

One step at the terrace edge is primarily a way to aesthetically close and lower the surface level. With several consecutive steps, however, a spatial structure is created that must maintain proper geometry, rigidity, and stability during repeated climbing and descending.

Therefore, several steps should not be treated as several independent terraces placed one after another on pedestals. In such a case, a much better solution is to create a common aluminum substructure.

Raised deck terraces – installation systems and technology for professionals

1 step

• Recommended solution: pedestals ; side finishing closure plate DDP CP

2 or more steps

• Recommended solution: aluminum substructure AluDeck

Large height difference

• Recommended solution: AluDeck substructure designed as several consecutive levels

Stairs finished with pavers

• Recommended solution: horizontal pavers ; vertical risers

Stairs with wooden/WPC decking board

• Recommended solution: AluDeck substructure ; surface adapted to the requirements of the decking board manufacturer

Stairs are a more demanding part of the terrace than its flat surface.

During normal walking on the terrace, loads act mainly vertically.

On the step, the user:

• presses on its outer edge,
• steps up and down dynamically,
• may also act on the structure horizontally,
• repeatedly loads the same section.

Therefore, with a single step, stabilization of the entire system is particularly important.

In the current installation solution, it is recommended to permanently stabilize the pedestals by properly fastening them to the substrate and additionally securing the pavers. The existing DD Group instructions also indicate that when creating a single step, the pedestals require stable fastening, and the pavers should be additionally secured against movement.

When gluing, use an adhesive:

• intended for exterior applications,
• compatible with the paver material and system components,
• resistant to moisture and temperature fluctuations,

according to the recommendations of the adhesive manufacturer.

If we need to build:

2, 3, 4 or more steps, the way the structure is designed changes.

In that case, we do not recommend building each step as a separate assembly of loosely standing pedestals and bottom fascia boards.

A much better solution is to create one rigid aluminum substructure that connects all the steps into a single unit.

For this application, the AluDeck system is designed.

The system uses aluminum profiles connected into a frame load-bearing structure. The AluDeck documentation describes the system as an integrated grid of aluminum joists, whose purpose is to increase horizontal stability and connect the individual structural elements into one frame.

What is particularly important in the context of this article, in the AluDeck system materials, the installation of steps is directly indicated as one of the applications of the system.

The aluminum substructure can still use adjustable terrace pedestals.

This means we can simultaneously:

• create a rigid staircase structure,
• adjust its height,
• adapt the structure to uneven ground,
• level individual sections.

AluDeck has dedicated adapters mounted on the pedestals in a "click" system.

Depending on the solution, you can use, among others:

• ADEC-ACA adapter,
• ADEC-LE self-leveling heads,
• STANDARD pedestals,
• CLEVER LEVEL,
• MAX,
• SPIRAL.

AluDeck documentation specifies that profiles are attached to the pedestals using dedicated "click" adapters; with self-leveling heads, automatic leveling of ground slope up to 6% is also possible.

With a standard terrace, we primarily need to achieve one target level.

With stairs, we have several levels:

terrace level → step 1 → step 2 → step 3 → ground level.

Therefore, before installation, you need to precisely determine:

• the total height difference,
• the number of steps,
• the height of each step,
• the depth of each step,
• the target level of the first and last step.

Adjustable pedestals make it easier to precisely set the entire substructure later.

How to plan the height of stairs?

Let's assume there is a specific height difference between the terrace and the garden level.

You should not first build successive steps and only at the end check what height remains.

First, you need to determine:

the total level difference

and only then divide it into an appropriate number of as equal steps as possible.

For example, the design scheme looks like this:

terrace level

↓

step 1

↓

step 2

↓

step 3

↓

ground level

The height and depth of the steps must be determined already at the design stage of the substructure.

In the case of stairs intended for pedestrian traffic, you should also consider the requirements resulting from the building's purpose, the design, and applicable regulations.

Remember the paver thickness when calculating the step height

This is a very common mistake.

The height of the aluminum substructure is not the height of the finished step.

You still need to add the thickness of the finishing material to the structure.

If, for example, we use a ceramic paver with a thickness of 20 mm, its thickness must be taken into account already when setting the height of the aluminum frame.

This applies to each successive step.

What is the minimum height of a raised deck terrace on pedestals?

When designing stairs, it is worth distinguishing between two elements:

This is the horizontal surface of the step on which we place our foot.

Measure the distance between:

the level of the finished terrace

and

the level at which the stairs are to end.

Do not base the measurement solely on the existing structural substrate – we are interested in the final level of the finished surfaces.

Based on the available space, determine:

• the number of steps,
• their height,
• depth,
• the width of the entire staircase.

All steps should form a consistent and predictable layout.

From AluDeck profiles, create a substructure that matches the geometry of the stairs.

Horizontal profiles provide support for the treads.

Vertical and cross elements allow for creating additional levels and proper stiffening of the structure.

Select pedestals suitable for the required height ranges.

For uneven or sloped substrates, appropriate self-leveling solutions can be used.

Then level all elements of the structure and check the geometry of the subsequent steps.

The profiles should be connected with the appropriate system components.

In AluDeck, the following connections are available:

• longitudinal,
• transverse,

which allows you to create a common frame instead of a set of independent profiles.

After completing and checking the substructure, you can begin installing the actual surface.

In the case of pavers, these will be:

horizontal pavers – treads

and

vertical pavers – risers.

Only then do we get the finished stair geometry.

And what about water drainage under the stairs?

Stairs built at a raised deck terrace should not block the primary function of this system.

Water passing through the gaps in the surface should still be able to drain freely over the layer below.

Therefore, when designing the structure, attention must be paid to:

• the existing slope of the substrate,
• drainage points,
• waterproofing,
• the contact points of vertical cladding with the substrate.

Vertical elements should not be designed in a way that accidentally creates a closed barrier for draining water.

Drainage of a raised deck terrace - how does it work and how to do it correctly?

Can you build stairs without AluDeck, using only multiple pedestals?

Technically, there are many ways to create an individual structure.

However, we do not recommend building several consecutive steps as a set of independent pedestals and pavers.

With one step, the structure is relatively simple and we can use the DDP CP plate.

With several steps, we recommend switching to a rigid, connected aluminum substructure AluDeck.

This is the most important rule of this article:

1 step – universal side finishing closure plate.

Can stairs be made from the same material as the terrace?

Yes – and this usually gives the best visual effect.

If the terrace is made of ceramic, concrete, or stone pavers, the same pavers can be used as:

• the terrace surface,
• treads,
• vertical risers.

For terraces made of decking boards, the surface material can similarly be continued on the steps, provided the appropriate substructure and fixing method are used in accordance with the board manufacturer's requirements.

The most common mistakes when building stairs on pedestals

Several consecutive levels should form a stable whole. Therefore, for a larger number of steps, we recommend AluDeck.

The height of the structure must be calculated to the top surface of the finished surface, not to the top of the pedestal or profile.

The geometry of the entire staircase should be determined before starting installation.

The step edge is one of the most heavily loaded areas of the structure.

The vertical finish of the stairs must not interfere with the drainage system under the terrace.

First, the geometry and heights of the structure must be determined, and only then should the required pedestal ranges be selected.

One step or AluDeck – which to choose?

A very simple rule can be adopted:

Use:

adjustable pedestals ; universal side finishing closure plate DDP CP.

This is a simple solution that allows you to aesthetically complete both the step surface and its vertical finish.

Yes. However, the method depends on the number of steps. For a single step, the universal side finishing closure plate DDP CP can be used. For multiple steps, we recommend constructing a rigid frame using AluDeck aluminum profiles.

To make a single step, you can use adjustable pedestals and the universal DDP CP plate, which allows for mounting a vertical paver forming a riser.

For two or more steps, it is recommended to create a common aluminum substructure AluDeck. Horizontal and vertical profiles form a frame defining the geometry of the subsequent steps.

We do not recommend building several consecutive steps as a set of independent pedestals. For such a structure, it is better to use a connected aluminum frame.

A stair tread is the horizontal surface of a step on which we place our foot.

A riser is the vertical element between two consecutive steps.

Yes. This is a very popular way to finish stairs on paver terraces, as it allows for a uniform aesthetic across the entire surface.

Yes. Aluminum profiles can be mounted on adjustable terrace pedestals using appropriate adapters. This allows the height of the substructure to be adjusted to the existing substrate.

No. AluDeck profiles can also be used as a substructure for wooden and WPC decking boards. The installation method of the decking surface should be adapted to the requirements of its manufacturer.

Yes. The geometry of the structure should always be calculated to the top surface of the finished step. If the paver used is, for example, 20 mm thick, this value must be taken into account when determining the height of the substructure.