Do I Need to Screed my Floor?

What is Screed?

Screed and concrete are often referred to as the same material, but they are actually very different. Concrete is a structural and very versatile building material, whereas screed has just one general purpose: to provide a smooth and strong floor covering.

Whilst screed and concrete have similar raw materials, they contain different aggregates, offer different strengths, and have a different finish.

Concrete is used for construction, and so it needs to be much stronger. As a result it uses larger, more coarse aggregates such as gravel or stone. Screed on the other hand, uses far fewer aggregates, and the aggregates that are used are very fine, such as smooth sand, to create a smoother, more liquid mix.

Screed is generally more liquid, making it easier to pour and resulting in a flat, smooth finish. It doesn’t offer the same strength of construction concrete, but it is still very durable, resilient and long lasting.

It provides a flat, even and smooth surface ready for a final floor covering, such as carpeting or laminate flooring systems. However, it is becoming much more popular in both commercial and residential spaces to leave the screed exposed, where it can be stained, polished or stamped with a decorative pattern to complement industrial interior decor.

Screed can also be used to set an underfloor heating system into place. It naturally retains heat, so it is the ideal material to secure and protect the pipework and heat the space.

Types of Screed Systems

Whilst screed has one general purpose, it can be installed in a range of ways to suit a variety of needs and offer a range of different benefits. Below are the main types of screed available:

Bonded Screed

A bonded screed system is poured directly onto the substrate (often a concrete subfloor) below, creating a completely bonded screed system.This is usually poured to a thickness of between 25mm and 40mm, and is the best option for construction projects where the finished floor will experience heavy usage, such as from vehicles.

Floating Screed

A floating screed system is poured directly onto a membrane that covers a layer of insulation, so is used when the flooring needs to incorporate a layer of thermal or acoustic insulation. This is usually poured at a thickness of 30mm to 40mm, and is best used in builds that want to boast increased energy efficiency.

Liquid Screed

Liquid screed, or self-compacting screed, is mixed to ensure a smoother surface, and speedy curing process. It’s thickness will depend on whether it is being poured on a bonded or unbonded floor and it is often used in projects with an unusual shaped floor, as the liquid screed will more effectively fill corners.

Unbonded Screed

Similarly to floating screed systems, an unbonded screed is directly poured onto a membrane that sits on top of the concrete subfloor. This membrane is used to damp proof, and prevent the final screed layer from shrinking, or drying too fast and cracking, distorting or curling.

Underfloor Heating Screed System

All the screed systems above can be laid over underfloor heating systems. Screed is thin material and a natural insulator so it retains and spreads the heat evenly across the floor.

The Benefits of a Concrete Screed Floor

If you’re installing underfloor heating, screed is the ideal material for your concrete flooring. It provides a strong and durable base for the final floor covering, and ensures the pipework is well protected. Another benefit to consider is the natural insulating qualities concrete screed offers, it retains and spreads the heat across the floor. It can also level an uneven floor, and is entirely draught proof.

The Curing Process

Screed sets quicker than concrete, so while your concrete floor may have taken a few weeks to set, your screed should only take a few days before you can cover it with your chosen final flooring.

However if the floor area is going to be under regular, heavy use, such as in a commercial setting, or if the area is particularly large, it should be left longer to ensure the structural integrity of the floor.

It takes 28 days for all concrete products to reach their full strength, so after this time, you can be assured your screed is properly cured to it’s required strength.

Always follow your supplier’s recommendations about the time it takes to cure, to ensure the best results.

Leveling the screed

Screed is much easier and quicker to level than concrete. Often you can choose a screed or an additive that makes it self-levelling, but in most projects, once the screed is poured over the sub floor (and pipework if you’re installing underfloor heating) it simply needs to be smoothed with a wooden float to level it.

Contact Us Today

If you’re looking for a screed supplier, contact the team at All Mix Concrete today. We have an expert team on hand who can chat to you about the best type of screed for your requirements, and we can provide concrete pump hire to ensure a fast and convenient delivery.