Decking Planning and Advice

Decking planning and advice

Decking can change the whole look and purpose of a garden, and for clients looking for what adds most value to a house, decking can add a further 2% on the overall house price. With this in mind, it’s easy to see why decking continues to be a popular choice for landscaping projects.

If you’re working on a project for your clients, it’s likely that decking will come up. We don’t want to tell you things you already know, but we’ve put this together as a bit of quick reference guide that might help, and also answer some questions that customers might ask.

Deck layout – planning and measuring

If you’re thinking to yourself, ‘how much decking do I need?’ planning the area out in a solid square or rectangle first will help to keep it simple, then you simply need to multiply the width by the length.

Decking measurements


Not all garden decking will be as simple as this. For unusual shapes, plan each section out in squares, slightly over-estimating for awkward corners. When you’ve planned out the sections and laid them out on a sheet of paper with your measurements, mark them out on the lawn with string and stakes, or pegs.

Decking plan

Things to consider:

  • Check the depth and position of underground pipes or cables
  • Avoid blocking access to manholes covers
  • Check for any drainage issues - decking needs good airflow and ventilation


How to install decking

  • Use 75mm galvanised screws for durability.
  • When joining boards, this must be done over a joist. Add more joists as necessary
  • Make sure screwheads are countersunk below the decking surface to avoid catching feet. Advise the home owner to check this every couple of seasons.
  • Leave 25mm at the ends of decking boards to allow for fixings

Fixing decking to a wall

If attaching your decking directly to a house, the top of the decking must be two brick courses or more below the damp proof course. This might not always be possible, so it’s best not to attach the decking to the wall at all, leaving a gap between the house and decking with draining running in between. You will also need to bolt a ledger board to the wall to support the joists.

Raised decking or laying decking on grass?

Garden decking can be placed at ground level or your customer might choose a raised deck design. There are reasons to choose either, but it’s often down to even and level lawns that come up to meet the doors and entrance ways. However, there’s sometimes a need for decking to be raised and the effect can give a garden a really attractive new look.

How to lay decking on grass

There are many reasons for laying decking on grass, but it’s not always as simple as it might seem. For an effective, stable decking it’s not simply a case of laying the decking directly on the ground and decking should never be laid directly onto grass itself.

Firstly, dig out an area the size and shape of your plan, removing a 5cm layer of turf. It’s a good idea to lay down weed control landscaping fabric after this is dug out, controlling weed growth safely by heavily reducing light to the ground. Landscaping fabric is a great ‘inside trick’ for projects, and can also be used under gravel paths and paving slabs, preventing sinking. Alternatively, you can use a permeable membrane with pierced holes instead.

At this point, build a series of wood sub-frames for the decking to rest on. These sub-frames will sit in the areas you’ve dug out and you’re all set to add your decking. You can also use concrete paving slabs for stability.

Decking step by step

Building a raised deck

When building an elevated deck it’s, as you might expect, slightly more involved than ground level decking. Firstly, depending on how high you build the decking this might require planning permission. The general rule is that if the decking doesn’t exceed 30cm above ground then you shouldn’t need permission from the council. It’s also a good idea to speak to your neighbours too, as complaints from other people near you can affect planning permission.

The stages for building a raised decking area start off similarly to a ground level deck, with mapping out and marking the area where you want it to go. However, when it comes to the sub-frame, this is needs to be taller and therefore more supported.

Decking posts should be positioned at 180cms, or under, apart, and half the length of the post should be dug into the ground and set in concrete. Because of an elevated deck construction, you may need to think about fitting decking balustrades and deck handrails, as well as timber decking steps.

Types of decking

There’s plenty of variety for your customer when choosing decking that suits their needs, usually coming down to deciding between the benefits of timber or composite decking. Let’s take a look at the options available to help your customers decide what might be the right choice for them.

Timber decking boards

There is something pleasing about the look of timber decking, which feels comforting in warmer months. Treated timber decking is a popular choice and long lasting as long as it’s well taken care of to prolong the life of the wood.

Timber DeckingTimber Decking Decking

Hardwood decking

Hardwood deck boards bring a luxurious style and feel to the garden, with the added bonus of not needing ongoing treatment. That’s right, you can simply lay these decking boards down and they’ll resist the harshest of weathers and wear.

Hardwood DeckingHardwood Decking

Composite decking

Also known as wood plastic or WPC decking, composite decking offers the best of both worlds when it comes to long-lasting material and cost of deck boards. How is composite decking made? It’s 95% recycled raw materials, which creates a long-lasting, UV resistant material that’s very low maintenance. In fact, composite deck boards are resistant to rot, warping and splintering.

Composite DeckingComposite Decking