Building a garden bench is worth doing yourself if you want a sturdy seat in a specific spot, not a showroom piece that costs £300 and still rocks on uneven paving. The easiest build garden bench DIY version is a chunky timber bench: two framed legs, a simple seat, a backrest if you want one, and fixings strong enough to survive wet UK winters. Done properly, it is a weekend job with about £90-£180 of materials from B&Q, Wickes, Travis Perkins or a local timber merchant.
In This Article
- The Simple Bench Design I Would Build First
- Materials, Tools and UK Costs
- Before You Cut: Sizing, Site and Safety Checks
- How to Build a Simple Garden Bench
- Finishing the Bench for UK Weather
- Common Mistakes That Make DIY Benches Feel Wobbly
- When Building Is Better Than Buying
- Frequently Asked Questions
The Simple Bench Design I Would Build First
The best first garden bench is a straight 1.2-1.5m timber bench with two box-style end frames and three or four seat boards. It is forgiving, easy to square up, and strong enough for normal family use without needing clever joinery. If you can cut straight, drill pilot holes and use an exterior wood screw, you can build this.
I would avoid curved benches, storage benches and anything with angled compound cuts for a first attempt. They look tempting on Pinterest, then you spend half the weekend trying to make two uneven arms look intentional. A simple rectangular bench also fits neatly into most UK patios, lawn edges and small seating corners. If your garden is tight, pair it with ideas from our guide to small patio layouts so the bench does not block the route to the back door.
The design in plain terms
You are making:
- Two end frames from 45 x 95mm treated timber, roughly 45cm high and 42-48cm deep.
- Three seat boards from deck boards or planed treated timber, each 1.2-1.5m long.
- One rear rail or backrest if you want more comfort, set at a slight backward angle or kept upright for simplicity.
- Bracing rails between the legs so the bench does not twist when someone sits on one end.
For a first build, a 1.2m bench is easier to keep rigid. A 1.5m bench gives room for two adults but needs better bracing. Once you go beyond 1.6m, add a middle support or expect the seat boards to flex.
Why timber beats blocks for most gardens
You can build a bench from sleepers, concrete blocks or reclaimed brick, but treated timber is the most practical starting point. Sleepers look good but are heavy; one 2.4m softwood sleeper can cost £25-£45 and weigh enough to make the job awkward without help. Concrete block benches are cheap on paper, with blocks around £2-£4 each, but they need a level base and usually look unfinished unless you dress them with timber.
Treated C16/C24 timber is lighter, easier to cut and simple to repair. If a seat board splits after five winters, you replace one board, not the whole bench.
Materials, Tools and UK Costs
The cheapest solid bench is not made from the cheapest timber. Thin bargain boards flex, cheap screws rust, and untreated timber turns grey and rough before you have really had your money’s worth. I would rather spend another £25 on better fixings and exterior finish than rebuild the thing next spring.
For a 1.2m bench, budget roughly £90-£180 depending on timber quality and whether you already own the tools. A ready-made wooden bench from B&Q, Argos or Amazon UK often sits around £80-£220, while heavier hardwood benches from John Lewis or garden centres can run £250-£600. DIY makes sense when you want stronger timber, custom sizing or a better match for an existing patio.
Shopping list
- Treated structural timber: four to six lengths of 45 x 95mm or similar, usually £6-£12 per 2.4m length at Wickes, B&Q or Travis Perkins.
- Seat boards: three deck boards or smooth planed boards, about £7-£15 each depending on profile and length.
- Exterior screws: 65-80mm coated decking screws, usually £8-£18 for a box from Screwfix or Toolstation.
- Corner brackets: optional galvanised brackets at about £4-£10 per pack if you want extra stiffness.
- Wood preserver or decking oil: £12-£30 for a tin from Ronseal, Cuprinol or Barrettine.
- Rubber feet or plastic packers: £4-£12 to keep timber ends off wet paving.
If you already have exterior screws, a saw and a drill, the bench can come in under £120. If you need to buy a drill driver, add £50-£120 for a budget Bosch, DeWalt, Makita or Ryobi kit. Hiring a mitre saw for a day is usually £20-£35 from local hire shops, though a hand saw is fine if you take your time.
Tools I would not skip
You can bodge a lot of garden projects with a blunt saw and misplaced confidence. A bench is not the place. People sit on it. Sometimes two people sit on one end while balancing tea, plates and the usual optimistic British barbecue weather.
At minimum, use:
- Tape measure and pencil for marking every matching piece from the same reference point.
- Combination square for straight cut lines and checking the end frames are square.
- Drill driver with 3mm pilot bit and screwdriver bit.
- Saw, ideally a mitre saw or circular saw with a straight edge.
- Clamps to hold boards while you drill; a pair of basic clamps costs about £8-£18.
- Sandpaper or detail sander for edges people will touch.
If you are choosing cordless tools for this and future garden jobs, our guide to cordless garden tools is a useful reality check before spending £200 on a battery platform.
Before You Cut: Sizing, Site and Safety Checks
A garden bench fails in boring ways: it is too low, it rocks, the back angle feels odd, or the timber feet sit in standing water. Sort those things before you cut anything.
Get the dimensions right
For most adults, aim for a seat height of 43-46cm. A seat depth of 38-45cm feels comfortable without forcing people to perch. If you add a backrest, make it 35-45cm above the seat. You do not need lounge-chair angles for a garden bench; a slight lean is fine, but an upright backrest is easier to build and still works for short sits.
Good starting dimensions:
- Compact bench: 1.2m wide, 43cm deep, 45cm high.
- Two-person bench: 1.5m wide, 45cm deep, 45cm high.
- Child-friendly bench: 1.0-1.2m wide, 38-40cm high, with rounded front edges.
If the bench is going on a patio, check it against your table, planters and door swing. Our guide to patio dining set sizing uses the same clearance logic: leave enough room for people to walk behind seated guests without doing the awkward sideways shuffle.
Choose the site before the design
Put the bench where people will use it, not where it looks best in your head. A south-facing wall is lovely in March and unbearable in July. A damp lawn edge looks romantic until the back legs sink. Uneven paving is fixable, but the bench needs either adjustable packing or a flatter spot.
If the bench will sit on grass, add small paving slabs under each leg. A pack of budget 450 x 450mm concrete slabs is often £5-£8 per slab from B&Q or Wickes. That is cheaper than letting the leg ends soak up water all winter. If you are planning a bigger seating base, read our patio laying guide before you build furniture around a surface you might change later.
Lift and cut sensibly
Long treated timber is awkward rather than clever-heavy. HSE manual handling guidance is aimed at workplaces, but the basic point still applies at home: plan the lift, avoid twisting, and get help when the load is awkward rather than waiting until your back complains. The HSE manual handling guidance is worth a quick read if you are shifting sleepers, slabs or multiple wet timber lengths.
Wear eye protection when cutting, use a mask if sanding treated timber, and do the dusty work outside. Treated timber offcuts should be disposed of through local waste routes, not burned in a fire pit.
How to Build a Simple Garden Bench
This is the build garden bench DIY method I would use for a first outdoor bench. It uses straight cuts, visible screws and simple bracing. No hidden joinery. No pretending you own a workshop.
Cut list for a 1.2m bench
For a basic bench with a backrest, cut:
- Seat boards: 3 x 1200mm deck boards or planed boards.
- Front and rear legs: 4 x 450mm from 45 x 95mm timber.
- Side rails: 4 x 380-420mm, depending on chosen seat depth.
- Long front and rear rails: 2 x 1100mm, set inside the legs.
- Back posts: 2 x 800-900mm if you want a backrest.
- Back board: 1 or 2 x 1200mm boards.
Mark all matching parts together. Cut one leg, then use it as a template for the other three. Tiny length differences matter because they become wobble.
Build the two end frames
Lay two legs on a flat surface and screw a side rail between them near the top. Add a lower side rail 8-12cm above ground level. Drill pilot holes first. Treated timber can split near the ends, and split legs are not charmingly rustic when they are holding body weight.
Use two screws at each joint, offset slightly so they do not split the grain. Check the frame is square by measuring diagonally corner to corner. If both diagonal measurements match, it is square enough. Repeat for the second end frame.
Join the frames with long rails
Stand the two end frames upright and clamp the long front rail between them. The rail should sit just below the seat boards, inside the legs. Add the rear rail at the same height. Check the bench is not twisted before driving the screws home.
This is where cheap clamps earn their keep. Without clamps, one rail creeps up while you tighten the other and the bench ends up with a wobble that follows you forever. Ask me how I know.
Fit the seat boards
Lay the three seat boards across the frame with 5-8mm gaps between them. The gaps let rain drain and give the boards room to move. If you use deck boards, put the smoother face up unless the grooved side is designed as the walking surface by that manufacturer. Grooves can hold water and dirt, which is not ideal for a seat.
Screw each board down at both ends and into the middle support if you add one. Keep screws in neat lines because visible fixings are part of the finished look. If you want a cleaner front edge, leave a small overhang of 20-30mm.
Add the backrest
The simplest backrest is two taller rear posts fixed to the back legs, then one or two horizontal boards screwed across them. Upright is easiest. A slight lean feels better but needs angled cuts or packers behind the posts.
Set the first back board around 12-15cm above the seat, then add a second board higher up if you want support across the shoulder blades. Sit on the bench before final tightening. It is much easier to move a back board now than after you have oiled everything and declared yourself a craftsperson.
Add bracing if it flexes
Sit at each end and push sideways. If the bench twists, add diagonal bracing under the seat or a middle support leg. A 1.5m bench should usually have a middle support rail under the seat boards. Timber is cheaper than regret; one extra length at £6-£12 can make the bench feel twice as solid.
Finishing the Bench for UK Weather
The build is only half the job. UK rain, frost and summer UV will test exposed timber quickly, especially on end grain and horizontal surfaces. If you skip finish because the timber is pressure-treated, the bench may still survive, but it will age rougher and uglier.
Sand the places people touch
Round over the front edge of the seat, the top of the backrest and any arm-height corners. You do not need furniture-grade perfection. You do need to remove splinters, sharp saw marks and screw burrs. A basic detail sander is about £25-£45 from Screwfix or Amazon UK; hand sanding is slower but fine for one bench.
Treat the end grain properly
Cut ends are vulnerable because treatment does not always penetrate fully after you cut the timber. Brush on an end-grain preserver or exterior wood treatment before assembly if you can. A tin of Ronseal or Cuprinol exterior wood preserver is normally £12-£25 and will do several small projects.
Finish with decking oil, exterior wood oil or outdoor paint. Oil keeps the timber look and is easier to refresh. Paint gives more colour but chips and needs better prep. If your garden furniture already has a finish, our guide to oiling and maintaining wooden garden furniture covers the trade-offs in more detail.
Keep the feet dry
The leg bottoms are the first place I would protect. Add rubber feet, plastic packers or small paving pads so timber is not sitting in a puddle. If the bench stays out all year, lift it once a year and check the underside. Green algae, soft timber and black staining are early signs that water is winning.
For winter storage and covers, the same principles apply as with bought furniture: airflow matters more than wrapping everything tight. Our piece on protecting garden furniture over winter explains why sealed covers can trap damp if they are used badly.
The RHS advice on frost damage is plant-focused, but the weather lesson is familiar for garden materials too: repeated freezing and thawing punishes wet surfaces. Do not leave the bench where water pools around the feet.
Common Mistakes That Make DIY Benches Feel Wobbly
Most bad DIY benches are not bad because the builder lacked skill. They are bad because one small practical detail was ignored. The good news is that the fixes are cheap.
Using boards that are too thin
Thin seat boards feel fine for five minutes, then flex every time an adult sits down. For a 1.2m bench, deck boards or 38-45mm structural timber are safer than skinny decorative boards. For a 1.5m bench, add a centre support. If you want a slimmer modern look, use better timber rather than removing structure.
Screwing too close to the end
Screws near the end of a board split timber, especially if you skip pilot holes. Drill first, keep fixings at least 25-35mm from the end where possible, and avoid driving screws so hard that they crush the surface.
Forgetting drainage gaps
Seat boards should not be tight together. A 5-8mm gap lets rain escape and makes cleaning easier. If crumbs, leaves and water sit between boards, the bench gets grim fast. It is the same logic as patio drainage: water needs somewhere sensible to go, not a polite invitation to hang around.
Building for the perfect flat patio you do not have
Real patios slope. Lawns dip. Old paving slabs move. Before final tightening, put the bench in its actual spot and check for rock. You can trim one leg slightly, add plastic shims or set the feet on small slabs. Do not assume the kitchen floor test means anything outdoors.
When Building Is Better Than Buying
Build the bench if you need a custom width, a matching timber finish, a heavy frame for an exposed spot, or a practical project that gives you better materials for the money. Buy one if you want curved arms, ornate metalwork, hardwood joinery or a fast result with no sawdust.
Ready-made benches still have a place. A basic softwood bench from Argos, B&Q or Amazon UK can be cheaper than buying every tool from scratch. A better hardwood bench from a garden centre or John Lewis may outlast a rushed DIY build. Our garden bench buying guide is the better read if you want product picks rather than a build.
The sweet spot for a build garden bench DIY project is a simple seat that fills an awkward space: beside a raised bed, tucked against a fence, or sized to sit neatly on a small patio. If the rest of the area needs work, sort the base first. A bench on a poor patio just gives you a nicer place to notice the poor patio, and our guide to patio materials can help before you commit to the seating corner.
My preference would be treated timber, visible exterior screws, oil finish and small slab pads under the legs. It will not look like a £700 teak bench. It will look solid, cost sensible money, and be easy to repair. That is exactly what a first DIY garden bench should be.
Frequently Asked Questions
How much does it cost to build a simple garden bench in the UK? A sturdy timber bench usually costs about £90-£180 in materials if you already own basic tools. Add £50-£120 if you need a drill driver, saw or sander.
What timber should I use for a DIY garden bench? Pressure-treated softwood is the best first choice because it is affordable, easy to cut and widely available. Hardwood lasts longer but costs more and is less forgiving for beginners.
Do I need planning permission for a garden bench? A normal movable garden bench does not usually need planning permission. Fixed built-in seating can become part of a bigger landscaping project, so check if it is tied to decking, raised platforms or boundary work.
How high should a garden bench seat be? Aim for 43-46cm from the ground to the top of the seat. Lower benches can feel relaxed but are harder to stand up from, especially for older relatives.
Can I build a bench without a backrest? Yes. A backless bench is easier, cheaper and useful beside a table or raised bed. Add a backrest if the bench is for sitting with a drink rather than quick perch-and-go use.
How do I stop a wooden bench rotting? Keep the feet off wet ground, treat cut ends, use exterior oil or paint, and leave drainage gaps between seat boards. Check the underside every spring before small damp problems become structural.