Whether you’re looking to create a stylish new sun-deck, a raised area for outdoor dining or just want an attractive feature to add variety, there’s no better way to enhance your garden than by installing traditional, wooden decking. The appearance of wood as a construction material can’t be beaten, as it looks great and will blend seamlessly into your garden all-year-round. Building a simple, wooden deck should be relatively straightforward for a competent DIY’er, so we’ve put together a Build your own DIY decking step-by-step guide to help get you started.

We are Complete Project Management (CPM) a local trusted devon building contractors who work within and around Exeter, Exmouth, Crediton, Tiverton, Newton Abbot, Chagford, Torquay, Paignton, Honiton, Wellington, Sidmouth and Exminster.


As with all DIY projects, the trick to installing flawless decking is planning and preparation. There are many factors to consider when installing decking such as shape, size, materials, obstacles, groundwork and whether or not it will adjoin your house. Allow sufficient time for planning and make sure you identify any potential difficulties before starting any work.

  • Draw a rough sketch of your decking design.
  • Mark out the edge of your planned deck area to see how it will look.
  • Once you’ve confirmed the overall size, draw a detailed, scaled plan of the area.
  • Include access hatches or cut-outs in the deck for manhole covers, airbricks and drains.
  • Consider how to accommodate obstacles such as waste water soakaways and doorways.
  • Make sure the decking is at least 150mm below the damp proof course (DPC) to protect your home and comply with UK building regulations.
  • Calculate the total decking area in square metres as this help you identify how many packs of decking you need to purchase.


The next step is to clear the proposed decking area and lay the foundation blockwork. The framework should not be laid directly onto the soil, as it will soak up moisture from the ground and cause the decking to rot, so you will need to lay a concrete foundation or position paving slabs under each corner to support the weight.

Deck Subframe

  • Set out the perimeter using stakes and string, clear all vegetation and exposed roots, and compact the ground beneath using a roller or Wacker Plate.
  • Lay a decking undersheet or weed control membrane over the proposed area to prevent weeds growing up through the decking and secure using pegs.
  • Position concrete blocks or paving slabs to support the decking framework.
  • Place squares of bitumen membrane on top of the concrete blocks to prevent moisture soaking up into the decking.

Tip: Allow a 10mm drop per metre to divert rainwater away from the decking and your home.


Once you’ve prepared the base and foundation blockwork, you’re ready to start construction.

Sub Frame

  • Start by building the subframe (or outer frame) using 150mm x 50mm joists, rustproof screws and external wood glue.
  • Position the frame on top of the foundation blockwork and secure using ‘anchor’ screws.
  • Attach the frame to your house (if applicable) using anchor screws and allow a 10mm gap for drainage.
  • Now fill the subframe with long joists spaced approximately 400mm apart and secure using rustproof screws.
  • Place short lengths of timber (or ‘noggins’) between the joists to strengthen the framework and secure using rustproof screws.

DeckWet Decking

  • Lay down the decking boards leaving a 5-10mm gap between them to allow for expansion and to provide ventilation.
  • Fix each board in place using rustproof screws; start by securing each end, followed by the central joists for added strength.
  • Be sure to stagger the boards if your deck is wider than the length of the decking boards being used.

Once you’ve finished building your new decking, there’s only one job left to do…. Enjoy it! There’s no better way to spend a summer’s day than by relaxing on your new decking with an ice cold drink and a bbq sizzling in the background. Building a simple deck should be relatively easy for a competent DIY’er but if you’re looking for something more adventurous or bespoke, we advise contacting a professional decking installer. CPM offer specialist decking solutions including design, installation and maintenance. Call us today on 01392 925045 or contact us online for your free, no-obligation quote.