Screed, Stabilisé, Concrete: Differences & Applications

by Staenis | 13/05/2021

What is traditional screed, what is stabilised sand, what is concrete?

Screed, stabilised sand and concrete all contain sand, cement and water. Each of these mixtures is used in the installation of floors and pavements. But what's the difference? What is screed, what is stabilised screed and what is concrete? And for which applications do you use them best? A crash course.

What is stabilised sand?

You've probably heard about stabilised sand, but what exactly is it? This mixture consists of cement, sand and some water. Because stabilised sand is quite water-permeable, it often serves as an underlayer for materials that are installed outside, such as clinkers, natural stone tiles, edging and paving. A stabilised bed is made, cement mortar is spread over it and the tiles or clinkers are knocked in. However, stabilised screed dries quickly, which means that the processing time is quite short (about three hours). By adding a delaying agent, you can extend the processing time by a few hours.

Tip: If you want to finish your terrace with ceramic tiles, it is best to use adhesive. In this case you have to use screed and let it dry out first so that the tile adhesive can adhere well. On ceramic tiles mainly only tile adhesives with additives adhere. Because the screed still allows some water to pass through (but a lot less than in the case of stabilised sand), you still risk frost damage and stresses in the screed. If you want to prevent the risk of damage due to moisture or tension, you can get started with the screed grating from Staenis where you use drainage mortar as a filler. The screed grid divides the screed in such a way that the tensions are enormously reduced. This way you don't need a drainage mat or decoupling mat. Discover all the technical advantages of the Staenis grid.

What is traditional screed?

If you have never built or renovated before, you may be wondering: what is screed? A screed forms the strong and indispensable basis for almost all floor finishes, such as floor tiles, laminate, parquet and carpet. Furthermore, a screed (also called stabilised sand) protects the utility pipes and ensures a long life for your floor. Like stabilised sand, screed is a mixture of sand, cement and water. Screed can be cement-based, such as traditional screed, or gypsum-based. There are therefore different types of screed: traditional screed, anhydrite flow screed, cement flow screed and insulating screed. Read more about the composition of screed, discover the right floor structure for your job and learn how to easily lay your own screed with a handy DIY system.

What is the difference between traditional screed and stabilised sand?

Difference 1: a different ratio of sand, cement and concrete

Screed has a ratio of 1 part cement to 4 to 5 parts sand, while stabilized has a ratio of 1 part cement to 8 parts sand.

Don't be fooled: if you don't know the difference between screed and stabilised sand, don't worry. After all, screed and stabilised sand have a lot in common. They consist of the same raw materials: sand, cement and water. So what exactly is the difference between stabilised sand and ordinary screed? To begin with, the proportions used vary. For traditional screed (also sand cement screed) the ratio is 1 part cement to 4 to 5 parts sand. Keep in mind that there are various types of screed, each with its own specific composition and applications. Find out here which screed proportions you should use best for your job. For stabilised sand, on the other hand, 1 part cement and 8 parts sand are usually used. Compared to stabilised sand, you use twice as much cement and extra water. Later in this article you will discover when it is best to choose screed, and when to choose stabilised sand.

Difference 2: stabilised sand allows water to pass through

Stabilisé allows more water to pass through than screed and is therefore often used for outdoor applications.

A second important difference between stabilised sand and ordinary screed is the water permeability. Stabilised sand allows water to pass much more easily. That is why stabilised sand is often used as a foundation for materials that are laid outside: natural stone terrace tiles, pavers for a driveway, footpaths and so on. Ordinary screed, on the other hand, is much less water-permeable and is usually used as a solid subfloor for tiles, parquet, laminate and so on. Good to know: screed is not the only material that you can use for a screed. In some cases it is better to choose (tileable) insulating screed, dry fillers or drainage mortar. Find here the ideal floor structure for your project and learn how you can save on the costs of screed work.

Difference 3: screed has a longer drying time

Screed has a longer drying time than stabilized, depending on factors such as layer thickness and ambient temperature.

Screed is a moister mixture than stabilised sand. As a result, the drying time of ordinary screed is much longer than that of stabilised sand, although it also depends on other factors such as the thickness of the layer, the ambient temperature and the sand used. As standard, a drying time of 28 days is recommended for a traditional sand cement screed. Because you have to take the thickness of the screed into account, the drying time can quickly increase to 56 days with a screed of 8 cm thickness. To speed up the drying time, you can opt for quick-drying screeds. They are a bit more expensive to purchase than traditional screed. Discover budget-friendly alternatives here for a shorter drying time of your screed.

Good to know: with the Staenis grid, a screed can always be tiled after 28 days, regardless of its thickness and the presence of underfloor heating. But there's more. A traditional screed with reinforcing mesh or fibres becomes uneven by up to 5 mm in the corners within a month after installation, but with the Staenis grid your floor will always remain nicely flat and perfectly in place. This means that floor coverings can be installed faster, easier and without risk.

Difference 4: a different approach to producing it

When making screed you first mix sand and cement and then add water, while with stabilized you can mix everything immediately.

When making screed, you first mix the sand and cement, and then add water. When making stabilised sand, you can mix everything right away. Learn how to make screed here. If you have to screed a large area, it is better to have a screed silo with prepared screed delivered to your site. Wondering how much screed you need for your job? Find the ideal floor structure for your floor here and use the handy quantity calculator.

Difference 5: Other Applications

Stabilisé wordt gebruikt als opvulmiddel en onderlaag, terwijl chape dient als stevige ondervloer voor diverse vloerafwerkingen.

Stabilised sand and ordinary screed each have their own applications. When to use screed and when to use stabilised sand? Stabilised sand is a drier mixture than screed and is more likely to be used as a filler. It serves as an underlayer for paving stones, as a supplement under foundations, as an anchor for piles or as a supplement around an inground swimming pool. Screed hardens better, but is not very permeable to water. Screed is therefore ideal for indoor use, but also comes in handy when gluing tiles outdoors. Indoors, it serves as a substrate for various floors, on which you can place your floor covering directly. Outside you can use screed to drain a flat roof or terrace. With this material you create a slope towards the drain, on which you can place insulation or waterproofing. Please note: laying screed is specialist work. A screed must be placed on a solid supporting floor, have a certain thickness or height and be flat. Leave the job to an experienced screed installer? You do not have to. Using the Staenis grid you can easily lay your screed yourself, even if you have no experience.

Tip: When constructing a tiled terrace, a tiled driveway or the foundation of a garden house it is best to use the Staenis grid in combination with drainage mortar. With this combo, moisture and tension have no influence on the lifespan of your new floor and you go for a good floor structure. Find out here which floor structure is suitable for your outdoor pavement.

What is concrete?

Concrete consists of sand, cement, gravel and water. For example, your question is 'What is the difference between screed and concrete?' answered immediately. But there is another important difference between screed and concrete. Concrete is used for applications other than screed. For example, you can use concrete for a load-bearing floor, which fulfils the load-bearing function of a floor and provides stability. A membrane is placed on the open ground, on which a concrete slab is then poured. An adhesive screed can be placed directly on a concrete supporting floor if the substrate is not porous and if there is no risk of cracks and rising damp. Discover the ideal floor structure for your project here.

A popular composition of concrete for a load-bearing floor is: 1 part cement, 2 parts sand and 3 parts gravel. The water part is about one-tenth of the solid parts. A filling layer of the pipes is provided with screed, insulating screed, sprayed PU or with dry fillers.

In addition, concrete can also serve as a final layer. Solid concrete floors consist of a solid concrete layer, which means that a screed is not necessary. Inside, concrete floors must be at least 7 cm thick, for outdoor use at least 15 cm. Polished concrete floors are the most common, but you can also opt for printed concrete, a washed concrete floor or a brushed concrete floor.

Screed or concrete?

A cement screed or screed is not the same as a concrete floor. The main difference is that a cement screed is a floating floor and a concrete floor serves as a finishing floor. A concrete floor consists of cement with possibly lime. The concrete is poured onto an even, stable subfloor and serves as the finishing touch for your floor. If you opt for a smooth concrete floor, pipes for sewers, electricity supplies, gas etc. can normally be poured into the concrete floor. You have to cover them with PVC. Central heating pipes and water pipes must not collapse under the weight, but must be fitted with a casing pipe that is at least 1 centimetre thicker than the pipe itself. So when you ask the question 'Screed or concrete?', the answer is: it depends on the purpose. If you need a screed, then screed is the logical choice. Concrete is a suitable option for a durable and seamless finish for your floor or a foundation.

What is traditional screed, what is stabilised sand and what is concrete? You have discovered that, among other things, the composition and the ratio used differ, so that each mixture has its specific applications. Fortunately, there is the handy floor construction tool, with which you quickly discover the ideal floor construction for your project. You always use the Staenis grid, a handy DIY system with which you can easily lay your screed yourself. You order the necessary materials online, in the Staenis webshop.