If you’re in the market for a new flooring system for your business, you need to make sure it’s up to the job. Depending on your business, the floor might need to resist chemicals, keep out water and at the same time provide enough grip to keep everyone safe.
Floor screed is a crucial part of making sure many floor surfaces are safe and level. But what is floor screed? Let’s take a closer look.
What Is Floor Screed?
Simply put, the answer to ‘what is screed?’ is a coating applied to concrete floors.
In many domestic and commercial settings, you don’t want to see the concrete floor. You might want to lay a final finish such as wood flooring or tiles. Or you may wish to include an underfloor heating system.
Floor screed provides a level surface over the concrete. You can lay your final finish over the screed.
Prepare your concrete and apply a bonding agent, then finish the surface with screed. Alternatively, lay the screed over a damp-proof membrane or an insulation panel.
Some types of screed make an excellent conductor for underfloor heating. They add to the system by effectively radiating heat from the coils or pipes. This produces both a level finish and an even distribution of heat.
What Types of Floor Screed Are There?
The right type of floor screed for your project depends on how the floor will be used. Screed can provide a level surface for applications as varied as homes, garages, and commercial kitchen floors.
Bonded screed fully bonds to the concrete subfloor by means of a bonding agent. You can apply this screed to concrete floors, beam and block floors, and precast planks. The screed usually goes on semi-dry and you need a relatively thin layer of around 25-40mm.
This is the right choice for heavy industry or floors that will take a lot of hammering. For example, factory floors, driveways, and car parks.
Floating screed can be laid on top of the insulation. This makes it a great choice in buildings that need acoustic insulation or have underfloor heating systems. It is laid to a much greater thickness than bonded screed, typically around 35mm and up to 75mm in certain situations.
Unbonded screed sits on top of a damp-proof membrane laid over the concrete slab. There are two main types of unbonded screed, sand/cement mixes and calcium sulphate mixes.
The membrane provides greater protection against dampness, but handle the curing process with care. If it dries too quickly, the perimeter of the screen can become distorted.
Sand and cement mixes will need a thickness of 50mm, whereas calcium sulphate can be thinner, at 30mm.
Underfloor Heating Screed
This type of screed is designed to be laid directly over underfloor heating pipes with no additional insulation. It provides a great medium for evenly distributing the heat throughout the whole floor surface. It comes in sand/cement, anhydrite and calcium sulphate formulations.
Depending on the screed used, it will require a depth of between 20mm and 75mm.
Resin and Polyurethane Screed
Resin and polyurethane screed are some of the best floor screed materials for industrial settings. They can provide an extremely hard-wearing floor finish for:
- Commercial kitchens
- Factory and warehouse floors
- Medical facilities
They can be applied with radius coves. This creates a floor to wall box finish which reduces the likelihood of bacteria forming in hard to clean corners.
They are available in poured, self-levelling formulations, as well as trowel-applied options. They can be directly applied to concrete surfaces. Epoxy resin screeds are available for levelling badly damaged concrete floors.
These floor screed materials are quick to cure – you can walk on them after 24 hours. Within 7 days, they have achieved full chemical and water resistance. They have high abrasion resistance and provide safe, non-slip surfaces.
What Is Liquid Screed?
Liquid screed can be a major timesaver, as it can be poured to create a level finish.
It’s suitable for both commercial and domestic settings. Depending on the type, it can be suitable for bonded, unbonded, floating, and underfloor heating applications. This type of screed can also be laid in thinner layers, meaning they dry faster and leave more room for insulation.
What Is the Difference Between Concrete and Screed?
Concrete is the structural material that gives the floor its strength. Whether your floor is made of concrete beams of it’s a poured concrete floor, it’s designed to be solid and permanent.
Screed is sometimes made from the same basic components as concrete. But its function is different. Screed acts as a final, smooth, level finish for floors.
A concrete slab may be rough, slightly uneven and not suitable for laying a final floor finish. Screed provides a level surface that will translate into an excellent, level final floor. Resin and polyurethane screeds provide a final finish without any extra flooring on top.
Do You Need to Screed a Concrete Floor?
That depends on the final desired outcome.
Screed is not essential to the structure, so is not strictly necessary. However, it is always recommended, because it provides a smooth, level final surface. Lay screed and you’ll avoid a bumpy, unsightly final floor finish.
How Do You Screed a Floor?
The floor screed procedure consists of 5 basic steps. Thoroughly research the floor screed requirements for the particular type before making preparations.
First, thoroughly clean your concrete floor. For a bonded floor, you will need to roughen the floor surface. For an unbonded floor, lay the waterproof membrane and any insulation.
Next, you’ll need to prepare your screed or arrange delivery of liquid screed. Divide your floor into sections and apply the screed, starting at the farthest corner. Use a straightedge to level the screed.
The best way to get a great final result is to employ a professional to do it for you.
Find the Right Floor Screed for Your Needs
Now you know the answer to ‘what is floor screed?’ the only question is which type will you choose.
The answer will depend on the type of floor you’re building. Floor screeds provide a fantastic, smooth finish that will ensure your final flooring looks great.