Decking

Garden decking is a great feature to have in your outdoor space. It can serve many functions, and improve the appearance of the entire space.

Garden decking is hard-wearing, and if the materials are good quality, it has a long lifespan. A deck is also a practical choice for outdoor seating as it supports heavy weights easily without any damage.

Garden decking is incredibly versatile, it can be used around ponds, pools, water features and even under pergolas. Garden decking is an inexpensive addition to your home, and yet it actually increases the value of the property as well.

Garden decking is sought-after feature for homebuyers, especially if they have a big family, as they add square footage onto the house and create the image of an idyllic lifestyle.

A simple ground-level timber deck usually costs roughly £35 to £45 per m² in materials. For composite, budget roughly £55 to £65 per m². The boards are the biggest cost. Our 32 x 125mm timber decking boards start from £9.52 for a 3m length, which works out at around £25 per m². Our Core composite decking boards start from £21.12 for a 3.6m board, around £40 per m². The rest goes on joists, screws and posts. Hiring a fitter adds labour on top.

It depends on the ground. On a slope or uneven ground, decking is usually cheaper. It sits on a timber frame, so there is less digging and no sub-base to build. On flat ground, paving often costs about the same to lay and less to own, because it never needs staining. Our porcelain paving starts from around £32 per m². You then need a compacted layer of Type 1 MOT under it, plus sand and cement for the mortar bed.

Gravel is the cheapest alternative. You lay a weed membrane, then spread gravel about 50mm deep. One bulk bag covers roughly 10m² at that depth. Our pea shingle and decorative gravels start from around £75 a bulk bag, so a gravel seating area can cost a fraction of a deck. Gravel drains freely and needs no frame. It is less comfortable for chairs and bare feet though. Some people use a few paving slabs as a firm base for a table.

The “4-year rule” was the time limit after which a council could no longer take action against building work done without planning permission. In England that limit is now 10 years for building work such as decking. So you can no longer rely on a deck becoming lawful after four years. The rules are different in Wales, Scotland and Northern Ireland. It is always safer to build within the permitted development limits, or to check with your council before they start.

In England, decking counts as permitted development only if it is no more than 30cm above the ground. Permitted development means you do not need planning permission. A raised deck taller than that needs planning permission. The deck must also meet three more conditions. It cannot sit in front of the house. Together with any extensions and outbuildings, it cannot cover more than half the garden and it cannot be at a listed building or flat. If your house is in a conservation area or National Park, check with your council.

You need a frame, fixings and a few finishing pieces. The frame is our pressure-treated decking joists, 47 x 100mm or 47 x 150mm. Space them no more than 40mm apart, and add a nogging (a short cross-piece) every 1.5m. Fix the boards with our deck screws, sold in boxes of 200. Use joist screws and angle plate brackets for the frame, and Postcrete for any posts. Lay a weed membrane underneath. For a rail, add a handrail fillet and turned spindles.

Timber costs more to maintain. A timber deck needs cleaning and a coat of decking stain every year or two to protect it. Over time some boards may also split or need replacing. Composite boards never need staining, oiling or sealing. You just wash them down. Our Core composite boards cost more upfront, but they come with a 10-year residential warranty. Over 10 years or more, the lower upkeep often closes the price gap. The joists under both types are timber, so check them now and then.

Late spring to early autumn is best. You want dry weather, and ground that is not frozen or waterlogged, so the posts and frame go in firmly. Pressure-treated timber is often still damp when it arrives. Leave a gap of around 5mm between boards so they can move as they dry. Wait until the timber has dried out before you apply decking stain, which usually takes a few month. Composite boards can go down in most weather, but always follow the fitting guide for expansion gaps.