Concrete works: price per m³ and m² 2026 and the process

Concrete forms the load-bearing skeleton of most buildings: foundations, floor slabs, ring beams, lintels, stairs and retaining walls. For anything structural, the concreter's years on the job do not decide the details. The structural engineer's calculation does. Foundation sizes, the concrete class, bar sizes and the layout of the reinforcement are always set out in the design drawings, and the crew on site simply builds what is drawn. Suppose someone decides on site to pour a thicker slab instead of putting in reinforcement, or to leave out a ring beam. That changes the structural design, and only a qualified structural engineer can approve it.

Building rules differ from country to country and often from region to region. Before you pour a base for a garage, a retaining wall or a large paved area, ask your local building authority what kind of approval the work needs. Do not assume a simple notification is enough until the authority confirms it. If you live in a block of flats and plan any work on a floor slab or a load-bearing wall, you also always need the consent of the building management or the owners' association.

Ready-mixed concrete is ordered according to EN 206, and its designation tells you much more than how strong it is. A specification such as C25/30 XC2 S3 Dmax 16 has four parts: the strength class, the environment the structure will sit in, how fluid the fresh mix is, and the largest stone size in the aggregate.

• Strength class: the first number is the strength of a test cylinder, the second the strength of a test cube, both in MPa. A lower class usually does the job for blinding concrete. For structural elements, the design sets the class.
• Exposure class: XC stands for the risk of carbonation. Over time, air and moisture slowly use up the protection the concrete gives the steel. XF stands for frost, XD for chlorides from road salt. A driveway that cars use and that gets salted in winter needs a different concrete from a foundation in dry ground.
• Consistency: classes S1 to S5 describe how runny the mix is. For pumping, people usually order S3 to S4, because a stiffer mix struggles to get through the pump.
• Aggregate: the stone size depends on how thick the element is and how dense the reinforcement is. Thin elements and tightly spaced bars need a smaller size.

In practice it often happens that someone adds water to the truck mixer so the concrete spreads more easily. Every extra litre, though, upsets the balance of water and cement, known as the water-cement ratio. The concrete ends up weaker and copes worse with frost. If you need a more fluid mix, order it from the batching plant with a plasticiser. Keep the delivery ticket from every truck. It shows the concrete class and the time of batching, and it is the only record of what actually went into your structure.

A site mixer makes sense for pad footings, small areas and minor jobs. Beyond that it simply cannot keep up. A base slab of 14 × 10 m and 20 cm thick holds 28 m³. That is four truck mixers of 7.5 m³ each, or hundreds of loads from an ordinary site mixer. Nobody could pour a slab like that by hand in one go and get even quality throughout.

If you are using ready-mixed concrete, think through these points in advance:

• Access for a heavy truck mixer: will the road take its weight, and is there room to turn
• The reach of the chute, which is only a few metres, so floor slabs, distant spots and areas behind the house need a concrete pump
• A steady flow of deliveries, so the layer already placed does not start to set before the next truck arrives
• Enough people and tools to spread, compact and level the surface
• Working time, as the mix usually has to be placed within about 90 minutes of batching, and sooner in hot weather

Order a little more than you calculate. Excavations are never perfectly level, and formwork bows slightly under the weight of the concrete. If you run a cubic metre short at the end of the day, you get a construction joint in a place nobody planned.

Foundations have to reach below the frost line, the depth that frost does not get to in winter. How deep that is depends on your climate and soil. In much of Central and Northern Europe it is usually at least 0.8 m, more in mountain areas and on some soils, while milder coastal regions often need less. Local building regulations or the building authority will tell you the usual figure for your area. The design sets the exact depth and width according to how much load the ground can carry. The bottom of the trench should sit in firm, undisturbed soil. If rain soaks it or turns it to mud, dig out the softened layer before you pour.

Some things belong in the trench before the concrete goes in, because adding them later is difficult or impossible:

• Foundation earth electrode: a steel earthing strip laid in the foundations according to the electrical design. Only a qualified, licensed electrician may design and connect it, and its testing is part of the handover of the electrical installation.
• Ducts and sleeves: for the drain connection, water, electricity and, where relevant, gas. Core drilling through a finished foundation later costs more and weakens the structure.
• Radon and damp protection: under a base slab, the membrane and insulation build-up depends on the local radon risk and the groundwater level. Blinding concrete beneath it gives a flat, firm surface to work on.

Fresh concrete pushes against formwork like a thick liquid, and a cubic metre of it weighs around 2.4 tonnes. The higher you pour and the faster you go, the greater the pressure. That is why tall walls are poured in layers. Traditional formwork made from boards and timbers suits unusual shapes, while system panel formwork suits walls and repeated elements. Coat the formwork faces with a release agent. Otherwise the concrete sticks to them and the surface tears when you strip the formwork.

Permanent formwork

Permanent formwork stays in the structure. It includes formwork blocks made of concrete or polystyrene, which you reinforce and fill, and lattice girder slabs. A lattice girder slab is a thin precast unit with three-dimensional lattice reinforcement sticking out of the top. It goes onto props, and the crew then pours a concrete topping over it on site.

Beam and clay block floor

This type of floor uses clay and concrete beams with lattice reinforcement and infill blocks set between them. The beams rest on the outer walls with the bearing length the manufacturer specifies, and they are not fixed with anchors. Put the temporary props under the beams at the spacing the manufacturer gives, not halfway between them. Then lay mesh over the blocks, form the ring beam and pour a structural topping over the whole floor. The brand names often used for these floors are just trade names, not a description of how the system works.

Stairs

On concrete stairs, vertical riser boards form the steps and set their height, and a sloping soffit board carries the whole flight. Every step must be the same height, and you have to allow for the thickness of the future floor finish both on the landing and at the bottom. Get the first or last step wrong by a centimetre, and it is very hard to fix once the concrete is in.

Why is there steel in concrete at all? Concrete handles squeezing very well but copes badly with being pulled apart. Steel takes the pulling forces, and the concrete in turn protects the steel from rust. This only works if a thick enough layer of concrete surrounds the bars. This layer is called the cover. It is usually roughly 20 to 50 mm depending on exposure and the type of element, and a lot more for concrete cast straight onto the ground. Spacers hold the bars at the right distance, and steel chairs support the top mesh in slabs.

Mesh sheets overlap, usually by one or two squares as the design specifies. A common sight is mesh lying flat on the ground, with someone trying to lift it with a rake during the pour. It nearly always ends up at the bottom of the slab, where it does almost nothing. For structural elements, the site supervisor or structural engineer checks the reinforcement before the pour and records it in the site diary.

Push a poker vibrator in vertically and at regular intervals. The gap between insertion points is roughly eight to ten times the diameter of the poker head. Keep vibrating until air bubbles stop rising and a thin film of cement paste appears on the surface. If you pour in layers, the poker should reach down into the layer below so the two bond together. Watch out for vibrating too long in one spot: the mix separates, the heavy stones sink and water with fine particles rises to the top.

For slabs and floors, a vibrating screed compacts and levels the concrete as it runs along level rails. Walkable and industrial floors get a finish with power floats once the concrete has firmed up a little. If the surface needs to be harder wearing, a dry shake hardener goes on at this stage. The window for this step is short. Float too early and you draw water out of the concrete. Float too late and the surface no longer closes up.

Concrete does not get strong by drying out. It hardens through a chemical reaction between cement and water. If the water evaporates from the surface too soon, the reaction stops and the surface stays soft, dusty and covered in a web of fine cracks. So keep the concrete damp for several days, usually at least a week: spray it, cover it with plastic sheeting or damp geotextile, or apply a curing compound.

• Summer: pour early in the morning, dampen the ground and the formwork, and shield the concrete from sun and wind as soon as you have finished the surface.
• Cold weather: at around +5 °C and below, concrete sets much more slowly. If frost reaches fresh concrete before it has gained its early strength, the damage is permanent. A warmer mix from the plant, an accelerator and a cover of thermal insulation all help.
• Striking the formwork: side formwork on walls and foundations usually comes off after a few days. Props under floor slabs stay much longer, roughly 21 to 28 days or as the structural engineer instructs. Removing them after 7 to 14 days without an engineer's assessment is risky.
• Contraction joints: large slabs and paved areas are divided into bays. The joints are usually sawn within 24 to 48 hours, to a depth of about a quarter to a third of the slab thickness. If you skip this, the concrete cracks wherever it likes.

A screed is not part of the structure. It is a layer that spreads loads and gives a level base for the floor finish. A floating cement screed laid on insulation is usually around 50 mm thick. With underfloor heating, follow the system manufacturer's guidance on how much screed must cover the pipes. Anhydrite (calcium sulphate) screed is poured as a liquid and levels itself, so it can be thinner. It is not suitable for rooms that stay damp or for outdoor use, though, and its surface needs sanding once it has hardened.

Many complaints start because someone laid the floor on a screed that had not dried. An old rule of thumb says cement screed dries roughly 1 cm per week for the first four centimetres. Thicker layers dry much more slowly. The only reliable check is measuring residual moisture with the calcium carbide method, with the result given in % CM. The flooring manufacturer sets the limits, typically around 2% CM for cement screed and around 0.5% CM for anhydrite screed. If you have underfloor heating, run it through a heating-up programme according to the protocol before the floor goes down.

Footings for a fence, pergola or garden shelter are well within reach of a handy homeowner. For a pergola or shelter, though, ask your local building authority before you start whether the work needs a notification or permit. Take care when digging because of buried services. If you hit a gas pipe or smell gas, stop at once, move to a safe distance and call the gas emergency line or the local emergency number (112). Any repair to a gas pipe is a job for a qualified, registered gas engineer.

1. Check the position of underground services with the utility companies and mark out the fence line with a string.
2. Dig a hole below the frost line for your area, often at least 0.8 m deep, and about three times as wide as the post.
3. Tip in a layer of gravel and tamp it down to drain water away from the foot of the post.
4. Set the post or post anchor, level it in two directions with a spirit level and brace it with diagonal battens.
5. Mix the bagged concrete exactly as the packaging says, with no extra water, and wear gloves and goggles, as cement irritates skin and eyes.
6. Place the concrete in layers, poke each layer with a rod to let the air out and keep checking that the post is still plumb.
7. Slope the top of the footing away from the post so water does not sit at its base, then keep the concrete damp for several days and protect it from frost.
8. Fit the fence panels only once the concrete has cured, roughly after a week, and heavy gates even later according to the manufacturer's instructions.

• The delivery tickets match the concrete class and exposure class in the design
• The reinforcement was inspected before the pour and the site diary records it
• Dimensions, levels and the positions of ducts and openings match the design
• The surface shows no honeycombing, voids or exposed reinforcement, and the edges are straight
• The flatness of slabs and screeds has been checked with a long straightedge
• Contraction and movement joints are sawn or formed as designed
• You know how the concrete was cured and for how long, and you have a record of the weather during the pour
• For screeds, you have a moisture measurement report before the floor finish goes down