How to build a raised deck terrace on the ground? A complete step-by-step guide

Ground-level terraces can be divided both by the type of finish and by the technology used for their construction.

The first method of installation is bonding tiles to a concrete slab. This technology, called a traditional terrace, has many drawbacks, such as the risk of tiles cracking and debonding.

The second method of installation is laying pavers or joists with boards on pedestals, which are placed on a concrete slab or stabilized ground. This technology is called a raised deck terrace, and it is this method that we focus on in this article.

The technology of a terrace on the ground is very simple and convenient. Appropriate materials and technical skills will allow you to handle such a challenge on your own.

It is important to choose the right material to finish the terrace, which can be:

• pavers - ceramic, concrete or stone
• boards - composite or wooden
• other materials - e.g. artificial grass on a grid substructure

Here we describe more about the individual materials, their advantages and disadvantages

See also: Types of surfaces used on raised deck terraces

We will discuss in turn the different types of substrates on which a raised deck terrace can be built on the ground.

1. Pavers (e.g. concrete paving slabs)
2. Concrete screed
3. Paving stones or posts (permeable pavers, paving stones, concrete posts)

Both wooden and composite decks are the most demanding ground-level decks in terms of the installation process, because they require specialized tools such as a jigsaw or a miter saw for cutting boards. These types of tools are not used when installing a deck with terrace pavers.

Typically, a ground-level deck is planned in residential gardens, and the initial area for the deck looks like the photo below.

The surface where the composite ground-level deck is to be built

Building a deck directly on soil or grass is not a good idea, because these are not durable substrates that will ensure the stability and durability of the structure.

With the first rain, the ground could shift and then all the deck components would be damaged. Therefore, soil stabilization is necessary, because the durability of the deck depends on it. You can do this using aggregate compacted in layers, e.g., a layer of gravel or a sand bed that has been compacted with a plate compactor, or a dry cement screed.

For residential decks, when determining the deck area, follow the height of the floor inside the house. Equally good indicators are the terrace doors, specifically the height of their threshold. The height of a ground-level deck includes: the thickness of the deck boards (both wooden and composite), the thickness of the joists, and the height of the terrace pedestals. You should also account for the construction of the base, whether it is a concrete slab, paving blocks, or another stable substrate.

If the ground is too high, consider removing the top layer of humus, or at least stripping its upper part – the turf. The minimum height for installing a deck is approx. 10 cm – below this height, there may not be enough space for the raised deck system to fit all the layers mentioned above.

The ideal free space height is 20 cm–30 cm, which allows for the free installation of the deck surface with pedestals.

The next step is to lay stabilizing elements at appropriate intervals; these can be paving blocks, concrete blocks, paving slabs, grid pavers, or even concrete curbs laid flat.

When our substrate is stable and the terrace structure will rest evenly on the elements used, we can proceed with further installation - spacing out the leveling components.

For this purpose, we place adjustable terrace pedestals on the stabilizing elements. We level them immediately to maintain the proper slope of the surface and to compensate for the slope of the substrate. To the leveled terrace pedestals, we attach aluminum, wooden, or composite joists. We screw them to special adapters.

The next and final step is laying the terrace surface, i.e., the usable terrace surface - wooden or composite deck boards.

The terrace installation should be carried out in accordance with building standards, and its correctness largely depends on the proper leveling of the pedestals and joists. It is worth re-checking the structural elements. If they have been disturbed earlier, we still have a chance to level them without disassembly and protect the terrace boards.

We install the boards according to the manufacturer's instructions (it is worth downloading them in advance from the manufacturer's website or asking for them to be provided at the time of purchase).

Now we are left with the most time-consuming work - the final cosmetic finishing of the terrace.

We proceed to install additional accessories - these may include fascia boards, corner brackets, end caps for boards at cut points, and similar materials. With their help, we will aesthetically finish the terrace on the ground.

You can find a helpful video here: instructional video shows how to make a raised wooden deck terrace. You will find information on what materials you may need, what is worth purchasing in advance, and what to pay attention to when building the structure.

Choosing a concrete screed allows us to build a terrace on a slab and space the pedestals at any spacing. On the terrace slab we place the pedestals depending on the size of the pavers. We can use various types of pavers, e.g., ceramic tiles, decorative concrete pavers, or stone pavers.

Before starting to set up the pedestals, the terrace slab (screed) should be cleaned. To properly select the pedestals, you need to know the height of the terrace, i.e., measure the distance from the concrete screed to the height at which we plan the finished terrace surface (usually to the height of the door threshold). From this, subtract the thickness of the tiles (natural stone and concrete pavers will differ significantly in thickness from porcelain tiles).

The minimum height for this type of terrace is 3 cm if we use a 2 cm ceramic paver (the lowest adjustable pedestal has a height from 10 to 17 mm).

The leveling pedestals were set up in such a way that after placing the ceramic pavers on them, their level is aligned with the interior flooring.

Making the terrace surface - installing the pavers on the pedestals.

In this case, large ceramic pavers, larger than the standard 60x60, were used for the finishing layer.

And now you just need to furnish the terrace to suit your needs.

We present an example based on a terrace renovation. The previously built terrace using traditional techniques looked like the image below after a few years - rotted wooden decking boards, house walls exposed to moisture, with visible mechanical damage.

The old, damaged wooden terrace surface on the ground was dismantled to create a raised deck terrace that would be resistant to moisture and weather conditions. The concrete slab was cleaned.

After cleaning the concrete slab, terrace pedestals were placed on it at intervals of 40-50 cm. Joists were laid on them, which were later covered with the final finishing layer - exotic wooden decking boards.

Here you can already see how the raised deck terrace on the ground looks after the renovation:

A raised deck terrace on such a large surface must be built in appropriate layers so that rainwater is properly drained.

The architects decided to use a solution with gravel. It is meant to serve as the drainage layer. This is a very popular solution for accumulating and slowly distributing water from terraces. However, due to its structure, it is not suitable for stably placing a plastic terrace pedestal on it.

The substrate should be stiffened with a concrete block placed on a concrete slab, and only then should the terrace pedestal, joists, and boards be set on the prepared substrate.

Then, terrace boards are laid on the structure of joists and pedestals.

Remember that when it comes to finishing, there are many options - the terrace can be made from concrete, ceramic, or stone pavers, but also from composite and wooden boards on composite, aluminum, or wooden joists.