Laying a Patio Yourself: UK Weekend Guide to Garden Paving
How to lay a 10–15m² patio properly — sub-base depth, mortar bed, cutting slabs cleanly, pointing — without the bowing, sinking and weed problems most DIY patios show within two years.
A patio is one of the most rewarding weekend DIY projects — visible transformation, immediate use, and a fraction of the £100–£140/m² a contractor charges. It is also the project most often done badly: poor sub-base, no fall, wrong jointing, and a slab field that bows or sinks within two summers. The good news is that the right way and the wrong way take roughly the same time and tools. The difference is sub-base discipline.
How much patio for one weekend?
A realistic scope for two people across one weekend is 10–15m² (roughly a 3×4m or 3×5m area). Larger areas are absolutely DIYable but become a two-weekend job — sub-base prep + slabs over a long weekend, pointing the following weekend once the bedding mortar has cured. Push past 25m² in one weekend and corners get cut, usually in the sub-base.
Tools you actually need
- Wacker plate (vibrating plate compactor) — £35–£55/day. Non-negotiable. Hand-tamping a sub-base never compacts enough.
- Cement mixer (small 90L electric is plenty for a domestic patio) — £20–£30/day on DIY Toolshare
- Wheelbarrow + builder's buckets — £8–£12/day or borrow
- Angle grinder with 4.5" diamond blade — £15–£25/day. Or a wet-cut tile/paving cutter for cleaner cuts and far less dust
- Long spirit level (1200mm minimum) or laser level — £8–£20/day for a laser
- String line, pegs, tape measure
- Pointing trowel, bucket trowel, lump hammer + bolster chisel
- Knee pads (you will thank yourself by hour three)
- Materials: paving slabs, MOT Type 1 sub-base aggregate, sharp sand, building sand, cement (or buy ready-mix bagged mortar to skip mixing)
Sub-base — the part everyone rushes
Failed patios almost always fail at the sub-base, not the slab layer. The slab is the thing you see; the sub-base is what carries the load. For a foot-traffic patio (no vehicles), the spec is straightforward:
- Mark out and excavate. Total depth from finished patio surface: 150mm (75mm MOT Type 1 sub-base + 50mm mortar bed + the slab thickness, usually around 25–30mm). Slope away from any building at 1:80 (1cm fall per 80cm of patio length) for drainage.
- Fill with MOT Type 1 sub-base aggregate, in two 35–40mm layers.
- Compact each layer with the wacker plate. Three to four full passes per layer minimum. Walking on it should not leave any footprint impression.
- Re-check fall and finished level with string lines or laser. The sub-base surface should be exactly the slab thickness + 50mm below your finished patio target.
Skipping the second compacted layer is the single most common mistake. One thick lift of aggregate never compacts as well as two thinner ones — the wacker plate cannot transmit force through the full depth in a single pass.
Bedding the slabs
Use a full wet mortar bed, not the five-dot "spot bedding" you may see on YouTube. Spot bedding leaves voids under the slab that fill with water, freeze, and crack the slab from underneath within a couple of winters. A 4:1 sharp sand and cement mix, mixed to a stiff (not sloppy) consistency, laid 50mm thick under each slab. Lay one slab at a time, tap level with a rubber mallet against a spirit level, then move on. Leave 8–10mm joints between slabs.
Cutting slabs accurately
You will need to cut slabs for the perimeter and around any drains, manholes or planters. An angle grinder with a 115mm diamond blade is cheap and fast but throws a huge amount of silica dust — wear a P3 mask, not a nuisance dust mask (see our MDF dust guide for the rating reasoning). A wet-cut tile/paving cutter rented for the day costs £25–£40 and gives a cleaner, dust-free cut with no chip-out on the visible face.
Pointing — three options
- Mortar pointing (4:1 sharp sand / cement, slightly damp): cheapest, most weather-durable, hardest to apply cleanly. Stains the slab face if you smear.
- Polymeric jointing compound (Romex, EasyJoint, Geo-Fix): brush dry into joints, mist with water, sets like rubber. Easy to apply, weed-suppressing, £30–£50 per 20kg tub. Best for most domestic patios.
- Kiln-dried sand: cheapest option, brushed into joints dry. Fine for permeable installations or where appearance is not critical. Weeds grow through eventually.
Falls and drainage
A flat patio against a house is a liability — rainwater runs back to the wall and finds a damp course defect within 12 months. A 1:80 fall (1cm drop per 80cm of length) is invisible to the eye but moves water effectively to a gully, lawn edge or a French drain. For patios over ~20m², two falls in a shallow V toward a central drain works better than one long single-direction fall.
Common mistakes that wreck the result
- Skimping on sub-base — single-lift aggregate, no wacker, end result sinks in tracks where you walked
- Spot bedding instead of full wet bed — slabs crack from voids holding water and freezing
- No fall away from the house — damp problems within a winter
- Cutting slabs dry with no mask — silica dust is a long-term lung hazard, not just irritation
- Pointing before bedding mortar cures (allow 48h minimum) — slabs slip under their own weight
- Walking on the patio for 48h after pointing — pressed-out joints pop loose
Frequently asked questions
Do I need planning permission to lay a patio in the UK?
Domestic patios fall under permitted development as long as the material is porous (or drains to a permeable area) and the patio is not raised more than 30cm above ground level. Front-garden patios over 5m² that drain to a road or pavement require planning permission since the 2008 SUDS regulations. Back gardens are usually fine.
What sub-base depth do I actually need?
75mm of compacted MOT Type 1 is correct for foot-traffic patios on most UK soils. Clay-heavy ground or known soft spots: 100mm. Anything that will take vehicle weight (driveway, not patio): 150mm minimum + edge restraints + different bedding method.
Can I lay paving directly on grass or soil?
You can — it will move within months. Roots, frost heave and soil settlement push slabs out of level. The sub-base + mortar bed combination is what stops that. Quick "stepping stone" paths through a lawn are a different story; full patios need the proper layers.
Mortar bed vs full wet bed — which is right?
Full wet mortar bed (a 50mm continuous layer of stiff 4:1 mix under each slab) for any patio that will see furniture, BBQs, foot traffic. Spot bedding (five blobs) is faster but creates voids that crack slabs in freeze-thaw cycles. Lay one slab at a time, tap level, move on.
How long before I can walk on a new patio?
After bedding: 24 hours before light foot traffic, 48 hours before pointing. After pointing: 24 hours before normal use, 7 days before furniture or BBQ weight. Avoid pressure-washing or heavy scrubbing for 4 weeks while the mortar fully cures.