People often design a patio starting from the house: “the width of the doors, and 3 m deep.” The result is rarely right. The table fits, but nobody can get behind the chairs; the garden sofa ends up on the lawn; the barbecue smokes out the kitchen.
Better to start from the other end: what you want to do on the patio, the furniture you have or will buy, and the time of day you'll sit out there. The area and the shape follow.
Start from the use, not the area
Measure the furniture you have. Then add 75 cm behind each chair so you can push it back and sit down, and at least 90 cm for a walkway. That gives realistic minimum sizes:
| Use | Typical furniture | Minimum size | Comfortable |
|---|---|---|---|
| Table for 4 | table 120 × 80 cm | 2.70 × 2.30 m | 3.00 × 3.00 m |
| Table for 6 | table 180 × 90 cm | 3.30 × 2.40 m | 3.60 × 3.00 m |
| Table for 8 | table 240 × 100 cm | 3.90 × 2.50 m | 4.20 × 3.20 m |
| Garden sofa set | 3-seater sofa, 2 armchairs, coffee table | 3.00 × 2.80 m | 3.60 × 3.20 m |
| Barbecue or plancha | grill and worktop | 1.80 × 1.20 m | 2.40 × 1.50 m |
| Two sun loungers | 2 × 70 × 190 cm | 2.40 × 2.30 m | 3.00 × 2.50 m |
The areas add up, with walkways between them. A 6 × 4 m patio, 24 m², takes for example a table for six (3.30 m), a 90 cm walkway and a 1.80 m barbecue corner across its full depth. To add a sofa set, you need 8 × 4 m, or a second seating area elsewhere in the garden.
Two habits avoid nasty surprises:
- The route into the garden shouldn't cut through the table. If the doors are in the middle of the patio, the table goes to one side and the walkway to the other.
- The barbecue goes downwind of the table and away from the windows and doors of the house. In most of the UK and Ireland, the wind comes most often from the west and south-west.
Orientation, sun and shade
The guide draw a garden plan to scale covers the sun's path and the length of shadows. For a patio, what matters most is the time you'll use it:
- South-facing: sun almost all day, very hot at midday in summer. You'll want shade, movable or fixed.
- West-facing: afternoon and evening sun, the patio for summer dinners.
- East-facing: breakfast in the sun, cool in the afternoon.
- North-facing: in the house's shadow for much of the day, even in summer. Cool, but rarely the main patio.
For shade, a 3 m cantilever parasol covers a table for six. A deciduous tree gives shade in summer and lets the sun through in winter, but it takes years to grow and drops leaves and fruit. A pergola, fixed or with adjustable louvres, sorts the question out faster: the guide garden sheds, carports and pergolas explains how to size and place one.
Look at the views too. A patio facing the neighbour's window, 4 m from the boundary, won't get much use, even facing south. A hedge, a screen or simply moving it 2 m changes everything.
Choose the surface
| Material | How it's laid | In the sun | Maintenance | Worth knowing |
|---|---|---|---|---|
| Timber decking (treated softwood, hardwood, thermally modified) | Boards on joists and pedestals | Stays fairly cool | Cleaning, oil depending on the look you want | Can get slippery in shade, turns silver-grey naturally |
| Composite decking | Boards on joists | Can get very hot, especially dark colours | Cleaning | Expands: respect the manufacturer's gaps |
| Natural stone (Indian sandstone, limestone, slate, granite) | Slabs on a mortar bed or pedestals | Pale colours stay cool | Low, depending on porosity | Heavy, ages well |
| 20 mm porcelain paving | On pedestals, on gravel or bedded on mortar | Depends on the colour | Very low | Choose a slip rating suited to outdoor use |
| Block paving or clay pavers | On a sand bed over a compacted sub-base | Depends on the colour | Joints to top up now and then | Takes loads well |
| Stabilised gravel | Gravel in cellular grids | Stays cool | Raking, weeding | Permeable, but less comfortable under a table |
The choice also depends on what's around the patio. The same material as the floor inside extends the room into the garden; a permeable surface, such as gravel or decking on pedestals, lets water soak in and takes pressure off the drains. Around a pool the constraints are different: the guide where to put a swimming pool covers them.
The fall and getting rid of rain
A solid patio (slabs, porcelain, pavers) is never perfectly flat. It has a fall of 1 to 2%, or 1 to 2 cm per metre, away from the house. On a patio 4 m deep, the garden edge is 4 to 8 cm lower than the edge by the wall.
Three things to check before you fix the levels:
- The door threshold. The finished level of the patio stays below the threshold, so rain and snow don't come in. If you want a patio level with the floor inside, plan a channel drain in front of the doors, connected to an outlet.
- The damp-proof course and the air bricks in the wall. The usual advice is to keep the finished patio at least 150 mm below the damp-proof course. A patio built up too high against the house can block the air bricks that ventilate a suspended floor, or bridge the damp-proof course and bring damp into the wall. Find them on the wall before you decide the level.
- Where the water goes. To the lawn or a bed, a land drain, the rainwater tank or a soakaway. Not onto the neighbour's patio. A 24 m² patio in London takes about 14 m³ of rain in an average year, enough to fill a small tank.
Decking on pedestals lets water through between the boards. The ground underneath then needs a slight fall and to be permeable, or covered with a membrane and gravel, so it doesn't turn into a permanent puddle.
What goes under the patio
The surface sits on a base suited to your ground and to the use: strip the topsoil, lay a compacted sub-base of crushed stone, then the bedding layer. Thicknesses depend on the ground and the material: follow the manufacturer's guidance or the builder's advice.
It's also the last chance to lay what will be hard to add later:
- a duct for a cable to lighting, a socket or a future motorised pergola;
- a water pipe for a tap or an outdoor kitchen;
- a drain pipe for the channel drain.
Record their routes on the utilities level. The guide mapping underground pipes and cables explains what to note. And check that no lid of a tank, inspection chamber or septic tank ends up under the slabs.
Linking the patio to the house and garden
- The difference in level between inside and the garden decides the shape: patio at garden level, one or two steps, or a raised deck on a frame. A step 15 to 17 cm high with a going of at least 30 cm stays comfortable outdoors.
- The edge on the garden side: a sunken edging or a row of pavers lets you mow without finishing with shears.
- The paths leading from the patio to the shed, the vegetable patch or the gate: draw the real trips first, as the garden guide suggests.
- The light in the room behind. A roofed pergola or a shade sail in front of the living room darkens the inside too, all year round if it's fixed.
Do you need permission?
In England, according to the Planning Portal at the time of writing, there's no limit on the area of hard surface you can lay at or near ground level around the house, outside the front garden. In the front garden, covering more than 5 m² with an impermeable surface needs planning permission, unless the water runs to a lawn or border; permeable surfaces don't. Decking or any raised platform needs permission if it's more than 30 cm above the ground, and together with extensions and outbuildings it can't cover more than half the garden. For a listed building, you need permission for decking, and listed building consent may be needed for other works. Wales, Scotland, Northern Ireland and Ireland have their own rules. A raised deck can also overlook the neighbours, which the council will weigh up. Ask your council what applies to your project.
Draw it in Architektor
On the garden level, pick the Area tool (A key) and choose the type “Terrace”. Drag for a rectangle, or click each corner for an L shape or a curve. Then:
- The surface is chosen in the properties: wood decking, paving, old cobbles, travertine slabs, stone tiles, concrete or gravel. For composite, take wood decking and write “composite” in the Notes field.
- The area and the perimeter are shown. The area helps you order slabs or boards (add a margin for cuts), the perimeter helps you count edging.
- Furniture is drawn as simple areas of type “Other”: a 180 × 90 cm rectangle for the table, another 75 cm larger all round for the chairs. You see at once whether the walkway stays clear.
- Dimension lines (D key) between the patio, the house and the boundary are useful for quotes and for any application.
- The status “To build” shows the patio in red, like on planning drawings.
Create a variant for each idea: “South patio 6 × 4”, “West patio, L-shaped”. You can overlay them to compare, and go back to any version. With your own API key, the assistant can also do the first draft: “Add a 4 × 6 m wood deck south of the house.” A Gemini key then gives you a photo-style render from the garden. It's an image to help you picture it; the dimensions that count are the ones on the plan.
When you're happy with the patio, share the plan with the “Garden and outdoor” link with the builder or the landscaper. They open it without an account, measure it themselves and pin comments in the exact spot. For the work itself, a PDF to scale of the garden level is enough to set out the corners with a string line.