The Different Types of Liquid Screed (And Which One’s Right for You)

liquid screedThink about ordering from a restaurant menu of 10 pages. Then imagine it’s in another language.

The confusing options are what many face when deciding on the proper liquid screed. Add to this terms like anhydrite (a mineral) and laitance (prevents bonding in flooring) who knows where to start?

The good news is that it is not that difficult to choose the right product for you. First, you’ll need to take stock of where the liquid screed will install.

There are correct choices available by both use and existing structures. We put together the latest information to help you navigate the options.

Why Use Liquid Screed over Cement Mixes?

Most know that screeding tends to cost a bit more than traditional cement flooring. So, why is it preferable? There are good reasons liquid screed is worth the extra cost:

  • For contractors, the labor cost is much lower with a liquid screed than a traditional mix
  • For underfloor heating pipes, a thin layer of screed responds better than traditional mixes
  • Because of its thin liquid state at install, screeding levels uneven floors
  • Screed does not shrink like its cement counterpart. This ensures tile or other flooring stays put
  • Where traditional concrete has an annoying way of cracking, screed does not

For homeowners or businesses, the investment pays off over the long term.

How the Mixture is Different

As with any good recipe, it’s all about the ingredients. And, how much of each component is in the mix.

For screed, the amount of water is higher than cement. The aggregates are more delicate and smoother. Traditional cement contains larger gravel pieces.

Both mixes have the strength after drying. But, screed’s finer mix sets up even and smooth. Its density stays true without air holes and resists cracks.

Size of Screeding Area

Measuring the size of the area will help you choose what’s best. Preparing the mix onsite or having liquid screed come ready by a lorry is much different.

There are many labor hours in making it yourself. For small areas, this may be fine.

But for larger square footage, it is time-consuming and back-breaking work. If you are going it alone, plan on several trips back and forth with heavy buckets.

Fast Dry or Traditional

Depending on where you’ll be laying the screed, you may need a quick dry. And, using the quick drying type will get the space up and running within a day.

But, consider this if you’re DIYing the floor. There is little room for error as it begins to set within 5 minutes.

Traditional drying times are up to 6 days. But, you can correct mishaps while it’s still liquid enough to move around. This is the guide for drying times of a traditional mix:

  • One day per depth of 1mm of mix up to 40mm
  • Two days per thickness of 1mm over 40mm

Liquid screed must cure before any tile, or other flooring installs. And, moisture needs to test below .5% and less than 75% humidity.

Professionals use a hydrometer to gauge the moisture.

Flooring Options Over Screeding

Before deciding on the kind of screed to use, you will need to consider the flooring installing. For example, if you plan to tile, the options will make a difference in the results.

Liquid pump cement mix screed does not need any preparation for flooring. But, the pumped anhydrite screed will need sanding before tiling.

The difference here is more labor costs for sanding. And, the pumped cement mix version has a higher price.

How Liquid Screed Installs Over Substrates

There are a variety of ways screeding installs over subflooring. And, depending on the how the floor needs to hold up the choice is important.

For projects that include underfloor heating pipes, floating floor screed is perfect. The screed pours over insulation, keeping the heat where it belongs. These are other options:

Bonded Floor Screed

Bonded floor screed is ideal for areas prone to water. Or, where thinner sections of flooring are necessary.

The screed bonds to concrete subfloors with adhesives. PVA (polyvinyl acetate) or SBR (synthetic rubber based adhesive) bonds layers together.

The mix is essential for areas of flooring that will hold bulky items such as appliances.

Partially Bonded Screed

Partially bonded screed tends to save money over the bonded version. It must pour over a rough surface to work at its best.

And, the thickness is vital to ensure it doesn’t break over time. 50mm or more is best.

Unbonded Floor Screed

Unbonded screed installs over a subfloor without bonding to it. A polyurethane damp proof membrane goes in over the substrate.

Then, the liquid screed pours over it. The benefit is that if the concrete underneath should crack, it will not continue to the screed layer.

The membrane also impedes moisture.

Floor Screed Over Underfloor Heating

Screed over heating pipes has become a green measure for energy savings and comfort. The liquid screed sets up without air holes.

Because only a thin layer is necessary, it gives off superior warmth.

Polymer Floor Screed

The polymer version is a combination of screed mixed with large amounts of adhesives. The thin liquid is ideal for keeping moisture and chemicals from leeching out.

Important Liquid Screed Considerations

Those who work with the material know the timing of installation and the curing process is vital. Any missteps in these areas can render the flooring much less capable of doing its work.

A strict timeline for preparation, installation, and drying times are at every step. Working with a professional who has experience is vital. The investment and hard work should pay off for years to come.

We offer services and experience for every step of your flooring needs. Contact us to learn more about what will work best for you.

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