A beautifully installed deck is one of the most versatile additions you can make to your home. It creates an instant outdoor dining room, covers up uneven ground, and adds significant value to your property.
However, decking is also one of the most common DIY disasters we see. We have been called out to fix countless "wobbly" decks in Bristol where the joists were spaced too wide, or the wood started rotting after just two years because of poor ventilation.
At Joe's Fencing, we believe in doing things properly. While we always recommend hiring a professional for complex or raised decks, if you are planning a simple ground-level project, this guide will help you understand the crucial steps involved.
Step 1: Planning and Permissions
Before you buy any timber, you need a plan.
- Location: Where does the sun hit? A deck in the shade will need more maintenance to stop it becoming slippery.
- Height: In the UK, if your deck is more than 30cm (300mm) above the ground, you may need planning permission. This is especially true for terraced properties in Bristol where privacy is a concern for neighbours.
- Materials: Decide between Timber or Composite (see our previous comparison guide).
Step 2: Site Clearance and Ground Prep
The biggest mistake DIYers make is building directly over grass or soil without preparation. This leads to weeds growing up through the boards and dampness rotting the frame.
- Clear the Turf: Dig out the grass and topsoil to a depth of around 50mm.
- Level the Ground: If you are on the typical Bristol clay, this can be hard work. Try to get it reasonably flat.
- Weed Control: Lay down a heavy-duty weed control fabric. This is non-negotiable.
- Gravel: Cover the fabric with a layer of pea shingle or gravel. This aids drainage and holds the fabric down.
Step 3: Building the Sub-Frame (The Skeleton)
Your deck is only as good as the frame it sits on. You might buy expensive composite boards, but if the frame rots, the whole thing fails.
- Posts: Concreted into the ground (like fence posts) to provide a rigid anchor.
- Joists: These are the horizontal beams the boards sit on. For a standard residential deck, we typically use 4" x 2" (100mm x 47mm) pressure-treated timber.
- Spacing: This is critical. For timber decking, joists should be spaced no more than 400mm apart (centre to centre). For composite, which is more flexible, you often need to reduce this to 300mm. If you go wider, your deck will bounce when you walk on it.
Step 4: Protection (The "Joist Tape" Trick)
Here is a trade secret: use joist tape. This is a waterproof flashing tape applied to the top of your timber joists before you lay the boards. It prevents water from sitting on the flat timber surface and rotting the screws. It costs a little extra but adds years to the lifespan of the frame.
Step 5: Laying the Boards
Now for the satisfying part. Whether using screws or hidden clips, accuracy is key.
Expansion Gaps: Wood and composite expand in the heat and contract in the cold. You must leave a gap between boards (usually 5mm-8mm). If you butt them up tight, they will buckle and pop up the first time the sun comes out.
Fixings: Always use stainless steel or specifically coated decking screws. Standard steel screws will rust quickly and stain your beautiful new wood black.
Step 6: Finishing Touches
Once the boards are down, trim the edges with a circular saw for a perfectly straight line. Add "fascia boards" to the sides to hide the structural frame underneath for a neat, professional look.
If you have installed timber, give it a coat of high-quality decking oil immediately to protect it from the UV rays.
When to Call the Professionals
Building a deck is physically demanding. It involves moving tonnes of earth, carrying heavy timber, and hours of precise sawing.
If your garden is on a steep slope (requiring complex structural calculations) or if you simply want a flawless finish without the backache, we are here to help. We have the tools and the team to build stunning, safe decks in a fraction of the time it takes a DIYer.
Ready to enjoy your garden without the hard work?
Featured Image Image [A construction shot showing a completed timber sub-frame with joist tape applied, with the first few decking boards being screwed down] Image Alt Text [Building a garden decking sub-frame in Bristol] Tags Select Tags Decking Installation DIY Guide Garden Renovation Bristol Tips SEO Settings Meta Title Deck Installation Step-by-Step Guide | Joe's Bristol Meta Description Planning a DIY deck? Read our step-by-step guide to installation. From ground prep to joist spacing, we cover what you need to know before you start.