Ready-Mix vs Site-Mixed Screed: Which Is Better?
One of the first decisions on any screeding project is whether to mix on site or order a factory-batched ready-mix delivery. Both approaches have their place, and the right choice depends on the project size, site conditions, quality requirements, and programme constraints. Here's how we'd help you decide.
Site-Mixed Screed
Traditional site mixing involves loading sand and cement into a mixer or screed pump on site, adding water, and delivering the material directly to the laying area. It's been the standard approach for decades and remains common on smaller projects.
The primary advantage is flexibility. You can adjust the mix on the fly, produce exactly the quantity needed for each pour, and there's no dependency on delivery schedules. It also tends to be more economical on smaller projects where the minimum order quantities for ready-mix deliveries aren't justified.
The downside is consistency. Site mixing relies heavily on the operative's skill and attention. If sand is measured by the shovelful rather than a gauge box, if water is added by eye rather than measured, if the mixing time varies batch to batch — then the quality of each load of screed will vary too. And variations in the mix translate directly to variations in strength, density, and drying time across the finished floor.
We see this regularly: a site-mixed screed that tests perfectly in one area and fails in another, simply because the afternoon batches had more water added as the team got tired. It's not a fault of the material — it's a limitation of the process.
Ready-Mixed Screed
Factory-batched screed is mixed under controlled conditions at a batching plant, then delivered to site in mixer trucks. The proportions are precisely weighed, the mixing is thorough and consistent, and every load arrives with the same properties.
For larger projects — anything over about 50 square metres in our experience — ready-mix is almost always the better option. The consistency advantage alone justifies the slight cost premium. You get reliable strength, predictable drying times, and a uniform surface across the entire floor area. Quality control documentation is also easier to provide, which matters increasingly on commercial projects.
The practical considerations are delivery logistics and site access. You'll need space for the mixer truck, a clear route to the laying area (or a pump to reach further), and you need to coordinate delivery timing precisely. Once the truck arrives, the material has a working window — typically 2-3 hours for traditional mixes — so the laying team must be ready to go.
There's also the question of minimum quantities. Most suppliers have minimum order volumes, so for very small areas you may pay for more material than you need.
Proprietary Pre-Blended Screeds
There's actually a third option that sits between the two: proprietary pre-blended screed products. These are factory-formulated dry mixes that arrive on site in bags or bulk, requiring only the addition of water on site. They combine the consistency of factory batching with the flexibility of site mixing.
This is where products from our Ardex, Mapei, Tekcem, and Weber ranges come into their own. Each bag contains precisely proportioned cement, aggregate, and additives — you simply add the specified volume of water and mix. The result is a screed with guaranteed properties: known strength class, known drying time, known performance characteristics. No guesswork, no variation.
For contractors who want the quality assurance of a controlled mix without the logistics of ready-mix delivery, proprietary products are increasingly the preferred choice. They're also essential for specialist applications — fast-drying screeds, fibre-reinforced systems, and underfloor heating screeds all benefit enormously from the precision of factory formulation.
Making the Right Choice
As a general guide: for small domestic projects under 30-40 square metres where the specification is straightforward, site mixing with quality materials and good practice can deliver perfectly acceptable results. For anything larger, or where quality documentation is required, or where the floor finish demands tight tolerances, we'd recommend either ready-mix delivery or proprietary pre-blended products.
Where underfloor heating is involved, we'd always recommend proprietary products — the thermal performance requirements are too demanding to risk the inconsistency of site mixing.
Our Product Range
We stock comprehensive screed products from leading manufacturers including Ardex, Mapei, Tekcem, and Weber. Whether you need traditional sand and cement additives, fast-drying formulations, or specialist UFH screeds, we can supply the right product for your project. Call us on 0118 370 2060 for advice on product selection, or browse our full range online. We offer free delivery on orders over £600 ex-VAT.
