Deck block prep 101: The ultimate guide to preparing your ground

tamping ground with a tamp

Creating a stable foundation is arguably the most important step when building a floating deck.

In this blog post, we will go through all the steps needed to prepare your ground when using deck blocks as the foundation for your deck.

By properly ensuring these steps are followed, you will provide a firm foundation on which the deck blocks will sit extending its lifespan for years to come.

Step 1: Measure the Area

The first step in preparing the ground for a deck is to measure the area where you plan to build it. Measure the length and width of the area, and make sure that it is level and clear of any debris or obstacles.

Step 2: Mark the Area

Once you have measured the area, mark it with a spray paint or landscaping paint. This will give you a clear visual of the area where your deck will be built, and help you to ensure that it is the right size and shape.

Step 3: Remove the top soil and vegetation

Next, you will need to clear the area of any debris, rocks, or other obstacles. This includes removing any grass, weeds, or other vegetation, as well as digging up any roots or stumps. It is important to have a clear and level surface for your deck blocks to sit on.

To do this you’ll need a sod cutter for removing grass along with its roots, and a shovel to extract it.

For some sites you may need a pickaxe to loosen the top layer before removing with a shovel.

Topsoil can expand and contract in response to changes in temperature and moisture. In hot weather, topsoil can dry out and become more compacted. In contrast, in cold weather, topsoil can become saturated with water, which can lead to soil erosion and other issues.

By removing it, we ensure the deck blocks are sat on compacted stable earth. It’s also important to make sure you’re building on grade level earth.

What is grade level earth?

Grade level earth refers to the natural level of the ground before any construction or excavation takes place. It is the surface of the land before any grading, filling, or excavation is done.

Step 4: Compact the Ground

Compacting the ground is an important step when building a structure, as it helps to ensure that the foundation is stable and level. It is necessary to compact the ground before laying a foundation, to ensure that it can support the weight of the structure, and to prevent settling, cracking, or other issues.

Here are some common methods for compacting ground:

Hand Tampering: This is a manual method where a tool called a hand tamper is used to compact the soil by manually striking it with the tamper. It is a good option for small areas or tight spaces where a machine cannot reach.

Plate Compactor: This is a machine that uses a large, flat plate to compact the ground. The plate is powered by an engine and is vibrated to compact the soil. It is a good option for larger areas, and it is more efficient than hand tamping.

Rollers: These are machines that use a large cylinder or drum to compact the ground. They are often used for compacting soil, gravel, or asphalt and can be either static or vibratory. They are good option for large areas, and they are more efficient than hand tamping or plate compactor.

Rammer: This is a machine that uses a piston to compact the ground. It is typically used to compact soil in tight spaces or in areas where a roller or plate compactor cannot reach.

The method used to compact the ground will depend on the specific project and the desired look and functionality. It is important to consult with a professional landscaper, civil engineer, or contractor to choose the right method and equipment for your project.

Step 5: Lay a Weed Mat/Barrier

The process of laying a weed mat involves placing a barrier, typically made of a heavy-duty material such as landscape fabric or plastic, over the area where you want to prevent weeds from growing. The barrier is then covered with a layer of crushed stone or paver base.

Weeds can cause several problems when they grow under a deck:

Aesthetics: Weeds growing under a deck can make the area appear unsightly and unkempt.

Structural Damage: Weeds can grow through cracks in the decking or along the edges, potentially causing structural damage to the deck.

Allergies: Some weeds can cause allergic reactions in some people, which can be a problem if they are growing under a deck where people spend time.

Pests: Weeds can also attract pests such as insects and rodents, which can be a problem if they are growing under a deck.

The process typically begins by preparing the area by removing any existing weeds and grass. Next, the weed mat is cut to the appropriate size and shape to fit the area where you want to prevent weeds from growing. The weed mat is then secured in place with stakes or pins, making sure that it is tight and smooth. The final step is to cover the weed mat with a layer of mulch or decorative stone to hide it from view.

Gaining access to the weeds becomes a lot more difficult once the deck is in place, and so preventing weeds from growing in the early stages is a lot more effective that trying to resolve the problem at a later date.

Step 6: Lay a Gravel Base

After you have laid your weed barrier, you will need to lay a gravel base. This will serve as a foundation for your deck blocks, and will help to keep them level and stable. Spread a layer of gravel over the entire area where your deck will be built, and then use a rake to level it out.

Some common types of aggregate used for drainage in deck building include:

Crushed Stone: Crushed stone is a type of coarse aggregate that is made from crushed rock. It is often used as a base layer for decks, and is known for its excellent drainage properties. It allows water to flow through easily, while also providing a stable foundation for the deck.

Gravel: Gravel is a type of aggregate that is made from small, rounded stones. It is often used as a base layer for decks, and is known for its good drainage properties. It allows water to flow through easily, while also providing a stable foundation for the deck.

Pea Gravel: Pea gravel is a type of small, rounded aggregate that is typically made from crushed rock or natural stone. It is often used as a decorative top layer for decks and other landscaping projects, and is known for its good drainage properties.

Sand: Sand is a type of fine aggregate that is made from natural materials, such as rock or mineral particles. It is often used as a base layer for decks, and is known for its good drainage properties. Sand can help to fill in any small gaps between the deck boards and can help prevent water from pooling.

Paver base: Paver base is a type of aggregate that is typically used as a base layer for paving projects. It is a mixture of crushed stone, gravel, and sand that is used to create a stable and durable foundation for pavers.

Paver base is typically composed of a combination of large and small stones, which helps to provide a stable and durable foundation for pavers. The large stones provide stability and support, while the smaller stones fill in any gaps and help to create a smooth surface for the pavers to rest on.

Step 7: Install the Deck Blocks

With your ground properly prepared, you are now ready to install your deck blocks. Deck blocks are precast concrete blocks that are specifically designed to support decks and other outdoor structures. They are easy to install, and can be used to support both wood and composite decks.

Final thoughts

These steps outline the process of preparing the ground when building a floating deck on soil, but these steps can vary depending on the type of surface you’re building on.

Creating a stable base is extremely important for floating decks and when done correctly will ensure the longevity of your deck.

For further steps on how to build a floating deck please check out our 20 step guide here:

1 comment

  • Thomas Wasden Jr

    I’m guessing y’all must have taken this article from somewhere else. Otherwise, it seems strange you would talk about cast concrete blocks in Step 7 rather than your Tuffblock.

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