How to Screed a Floor

Would you like to find out how to screed a floor correctly?

This guide uses easy-to-follow instructions and images that you can follow along with.

So, let's take a look...

What is Floor Screed?

Screed is a thin layer of concrete that is typically poured over a floor base to help form a smooth coating on the floor. This helps to provide a strong foundation for the flooring. It is not the same as concrete but is quite similar.

Screed is smoother than concrete as it uses fewer aggregates than concrete to create the mix. It is usually added on top of concrete as a finishing layer.

What Tools Do I Need to Screed a Floor?

Below is a list of the tools you’ll need to screed a floor:

• Brush
• Bucket
• Mixing tool
• Straight edge
• Trowel

What Safety Equipment Do I Need to Screed a Floor?

Here is a list of the recommended safety equipment you’ll need to screed a floor:

• Safety goggles
• Gloves
• Overalls
• Dust mask

What Materials Do I Need to Screed a Floor?

Below is a list of the materials that you’ll need to screed a floor:

• Water
• Bonding agent
• Cement
• Sand

Preparing to Screed a Floor

Below is a list of things that you’ll need to do to prepare for screeding a floor:

• Remove everything from the floor
• Sweep away any dirt and debris
• Slightly dampen the floor to reduce suction

How to Screed a Floor Yourself

Here is a step-by-step guide on how to screed a floor:

Step 1

First of all, you will need to add water to the floor to dampen it. This will help to reduce suction.

Step 2

Next, mix 10 litres of water with 150ml of bonding agent and a 25kg bag of cement. If you are screeding a small floor, you can reduce these measurements as necessary. This will act as your primer.

Step 3

Next, apply the primer to the floor in a thin layer using a brush.

Step 4

Once your primer is down. Mix together the ingredients to create your screed. The mix you create will depend on the thickness of the screed you are laying and the size of the area. The floor screed mix will consist of a combination of cement, water, and sand.

Step 5

Begin brushing your screed over the primer.

Step 6

For the floor screed to be successful, you will have to work in bits so that it’s level. Complete a small area at a time by laying down the mixture and using a batten to create a level surface. Use a trowel to spread the mixture before levelling it with the batten.

Step 7

If you notice any dips on the surface, simply add some more mixture and continue to level it out using your trowel and batten.

Step 8

Once you have covered the entire floor and you’re happy that it’s level, you will need to cure it. Cover the floor with a polythene sheet and leave it to cure over several days.

Step 9

After a few days, you can then take the polythene sheet away and allow the drying process to start. You will need to leave the floor again for several days until the surface is completely dried out.

Step 10

Once your surface is completely dry, the job is then complete.

Types of Floor Screeding

Below is a list of the different types of floor screed:

Bonded Screed

A bonded screed will be bonded to the substrate with a binding agent or a primer. This type of screed is ideal for thinner flooring sections that are designed for holding up heavier options.

PROS

✔ Durable

✔ Can hold up heavy objects

CONS

✖ Requires primer

Partially Bonded Screed

A partially bonded screed is more affordable than the former but isn’t as durable. This type of screed needs to be at least 50mm to ensure that it can’t easily break with use. It also needs to be laid on a rough slab for the best results.

PROS

✔ Cheaper option

CONS

✖ Not as durable as other types of screed

✖ Requires certain measurements to ensure it doesn’t break

✖ It needs to be applied to a rough slab for best results

Unbonded Screed

This type of floor screed is not directly bonded to the sub-floor but is instead separated by a membrane. Unbonded screeds level out on their own and are made up of sand, cement, and sometimes calcium sulphate.

PROS

✔ Not bonded directly to the floor

✔ Levels out on its own

CONS

✖ Not as durable as some other types

Floating Screed

A floating screed is applied above the insulation. This screed insulates itself well and will require the right kind of insulation or edging foam to prevent cracking due to shrinkage. However, it is great for keeping the underfloor warm in the home.

PROS

✔ Provides good insulation

✔ It can be used with underfloor heating

CONS

✖ Requires the right kind of insulation

✖ Could be prone to cracking with shrinkage

Some professional companies will use liquid floor screed or latex floor screed, as these can create a smooth finish by simply pouring the mixture onto the surface without the need for a straight edge for levelling.

However, these types of floor screed tend to be difficult to apply if you don’t have the right tools or skills to do so, so these screeds should be left to the professionals.

Getting the Right Floor Screed Mix

A traditional and common screed is generally made up of a mix of one-part cement to four-parts sand. The consistency tends to be very dry and almost powdery inconsistency.

It is usually mixed in a cement mixer on-site so that the mixture is prepared and ready to apply right away as soon as it’s needed.

This type of screed requires minimal preparation and can easily be applied to the room using a trowel and straight edge (as we’ve explained in our step-by-step guide).

FAQs

Sources

https://concreteflooringsolutions.co.uk/blog/do-i-need-to-screed-a-concrete-floor
https://www.youtube.com/watch?v=k8qZQBV9eP0
https://www.youtube.com/watch?v=9BBvAA7iNwE
https://www.londonflowscreed.co.uk/types-of-floor-screed
https://www.easymix-concrete.co.uk/news/how-soon-can-i-lay-flooring-after-laying-screed
https://www.kingconcrete.co.uk/do-i-need-to-screed-my-floor