How To Build A Deck Over Concrete?

Welcome, DIY enthusiasts and homeowners! Are you tired of looking at that drab, cracked concrete patio or concrete slab deck in your backyard?

Do you wish you had a beautiful wooden deck for hosting summer barbecues and relaxing in the sun? Well we have good news: you don’t have to tear out that old concrete and start from scratch.

You can quickly build a stunning deck over your existing concrete slab with some know-how and elbow grease. So grab your tools, and let’s get to work. In this blog post, we’ll show you exactly how to build the perfect deck over concrete, step by step.

Whether a seasoned DIY’er or a first-time builder, you’ll enjoy your new outdoor oasis in no time.

Tools and materials for building a deck on a concrete slab 

Ready to tackle building a floating deck over a concrete slab? Great! Before you start, ensure you have all the tools and materials you’ll need to build a deck on concrete. Here’s your shopping list:


  • Circular saw or jigsaw
  • Power drill
  • Hammer
  • Screwdriver
  • Measuring tape
  • Chalk line
  • Level
  • Decking concrete anchors
  • Masonry drill bit
  • Safety glasses
  • Hearing protection


  • Pressure-treated lumber for framing
  • Decking boards (natural wood or composite)
  • Concrete anchors
  • Concrete patch or self-levelling compound (if necessary)
  • Railings (if desired)
  • Stair stringers and treads (if desired)
  • Deck screws or hidden fasteners
  • Waterproofing sealer or stain (if necessary)
  • Sandpaper or deck brush (if necessary)

It’s essential to ensure you have all the necessary tools and materials before you begin building a deck over concrete. This will help to ensure that the project goes smoothly and that you don’t have to make multiple trips to the hardware store. Building a deck on concrete can be a straightforward and rewarding DIY project with the right tools and materials.

How to build a deck over a concrete slab?

If you have a concrete slab in your backyard just begging to be transformed into a beautiful outdoor living space, you’re in luck! Building a deck over a concrete slab is a straightforward DIY project that can upgrade your home. Here’s how to do it:

Inspect the concrete slab

Check the condition of the concrete slab

Before you start building a deck on a concrete slab, make sure that the concrete slab is in good condition. Look for any cracks, major damage, or signs of settling that could affect the stability of your timber decking over concrete. If you spot any issues, you should address them before decking over concrete.

Check the levelness of the concrete slab

Use a level to ensure the concrete slab is level before building a timber deck over concrete. If not, you’ll need a self-levelling compound to even out the surface before building your timber decking on concrete.

Check the drainage

Check to make sure that the concrete slab has proper drainage. If it doesn’t, water could pool on your floating deck on concrete and cause damage over time. If you notice any drainage issues, you may need to install a drainage system before building or installing or building a deck on concrete.

Check for asbestos

The concrete slab may contain asbestos if your home was built before the 1980s. If you suspect that your slab contains asbestos, do not attempt to remove it yourself. Contact a professional asbestos abatement company to handle the removal.

Choose your decking materials

Determine your budget

Before shopping for decking materials, determine how much you will spend on your deck. This will help you narrow down your options and avoid overspending.

Consider your aesthetic preferences

Do you want a natural wood look, or are you more interested in a composite material? Consider what will complement your home’s exterior and your lifestyle.

Consider the durability of the material

Different decking materials have different levels of durability. Consider how much foot traffic your deck will receive and choose a material that can withstand it.

Consider the maintenance requirements

Some decking materials require more maintenance than others. If you want to spend less time and money on upkeep, choose a low-maintenance material like composite decking.

Consider the environmental impact

Some decking materials, such as natural wood, may not be the most environmentally friendly option. If sustainability is a priority for you, consider choosing a decking material made from recycled materials such as composite decking. 

Create a frame

Creating a frame is a key step when building a deck over a concrete slab. The frame provides the structure for the deck and supports the deck’s weight and occupants.

To create a frame, you must use pressure-treated timber treated with chemicals to resist decay and insect damage. Here are the steps to how to build a decking frame on concrete:

Determine the size of the frame

Measure the concrete slab’s dimensions and determine your required frame size. Ensure the frame is slightly smaller than the slab to allow for drainage.

Cut the timber

Cut the timber to the appropriate lengths using a circular or mitre saw for a timber deck over a concrete slab. Make sure that the cuts are straight and accurate.

Lay out the frame

Lay out the timber decking over the concrete slab in the desired configuration. Use a level to make sure that the frame is level and even.

Attach the timber

For fixing timber decking to concrete:

  1. Use anchor bolts.
  2. Drill pilot holes in the timber deck on the concrete slab and then use a hammer drill to drill holes in the concrete.
  3. Insert the anchor bolts into the holes and tighten them down.

Add cross braces

Add cross braces or sleepers between the frame members of the timber decking on the concrete slab to provide additional stability. Cut the braces to the appropriate length and stick them to the frame using galvanised screws.

Install joist hangers

Install decking joists on concrete along the length of the frame for laying decking directly on concrete. Joist hangers are metal brackets that allow you to attach the joists to the frame. Nail them into place using galvanised nails.

Finish building deck over concrete

When building a deck on a concrete slab, several important steps must be taken to ensure it is safe and functional. Here are some key points to consider after laying decking on concrete :

Install railings

When building a raised deck over the concrete slab, you may be required to abide by local building codes to install railings. Many different types of railings are available, including wood, metal, and composite options.

Stain or seal the deck

Treating the wooden decking on a concrete or composite material with a sealant or stain is essential to preserve it from water damage, fading, and other signs of wear. Ensure you adhere to the manufacturer’s directions for application and upkeep.

Install lighting

If you plan to use your deck in the evenings, consider adding lighting to create a warm and inviting atmosphere. Many different types of lighting are available, from simple post lights to more elaborate LED systems.

Add furniture and decor

Once the basics are in place, it’s time to add furniture and decor to make your deck comfortable and inviting. Consider adding a table and chairs, a grill, or even a fire pit to make your elevated deck over a concrete patio, for instance, a gathering place for family and friends.

Perform regular maintenance

To keep your deck looking its best, performing regular maintenance, such as cleaning, sealing, and replacing damaged boards, is important. This will help to ensure that your deck lasts for many years to come.

Which decking material is the best to build a deck over concrete?

So, there are many different options when it comes to decking materials to build a deck over concrete. A deck constructed from a natural wood deck on a concrete slab looks great, but it needs a lot of upkeep to stop it from rotting and falling apart.

PVC and aluminium floating decks are easy to maintain, but they can be pricey and don’t have the same warmth as real wood. However, if you’re looking for the best of both worlds then lok no further than composite decking.

Made from a mix of recycled materials composite decking looks and feels just like real wood but with less maintenance. It’s also tough against moisture, bugs, and sun damage, so you can enjoy your deck for years without worrying about it falling apart.

Plus, it’s eco-friendly so making it a good investment in the long run. Composite decking might be your best bet if you want a beautiful, easy-to-care-for decking on concrete slab.