Liquid Screed and Self-Levelling Concrete: A Tradesperson’s Guide to a Level Floor

Posted on: 28th October 2017

How the Screed Market is Changing!
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Last Updated: June 2026

Most homeowners couldn’t tell you what’s under their tiles or their engineered oak floor. Most tradespeople could talk about it for twenty minutes straight. Liquid screed and self-levelling concrete have replaced sand and cement on plenty of sites over the last twenty years.

The key to getting them right is setting your levels accurately before you pour, which is where a screed tripod comes in. This guide covers what liquid screed and self-levelling concrete are, how they compare, and how to use screed tripods on site.

In brief: Liquid screed is a flowing, self-levelling floor screed laid in place of traditional sand and cement. It dries faster, sits thinner, and works especially well with underfloor heating. A screed tripod is a height-adjustable tool used to set the correct floor level before pouring liquid screed or self-levelling concrete, so the finished floor comes out perfectly flat.

Liquid screed and self-levelling concrete

Liquid screed is a flowing, self-levelling alternative to a hand-trowelled sand and cement mix, pumped into place rather than laid by hand. You’ll hear it called flowing, calcium sulphate or anhydrite screed (although not all liquids screeds are anhydrite screeds!), and it’s become the standard on underfloor heating jobs because it flows around the pipes and conducts heat better than sand and cement does. It’s also thinner and protein free, so several manufacturers recommend it for commercial kitchens and hospitals. Expect around 1mm of drying per day up to 40mm, though anhydrite screeds can be force dried from around seven days by commissioning the heating gradually up to 55°C. Thermal expansion figures vary by manufacturer though, so you should check the datasheet rather than assume. Pumpable self-smoothing screeds in the UK, whether cement based or calcium sulphate, sit under BS 8204-7, and that’s the standard covering materials, design, site work and testing.

Self-levelling concrete works differently. It’s concrete with polymers added, so it flows and settles itself, holding its strength while giving a flatter finish, useful now that vinyl’s thinner and tiles are bigger. It’s poured or pumped in, brought to depth with a gauge rake, then a Dapple Bar breaks the surface tension and releases trapped air before it cures.

Setting a level floor with screed tripods

A screed tripod, or screed spider, is a height adjustable, three-legged tool with a threaded shaft and disc that sets your floor level before you pour. Start from a datum, usually a door sill, and match the first tripod’s disc to it with a laser level. Space the rest roughly 1500mm apart, transfer the laser level to each one in turn, and adjust every disc until they match. Then just pour the screed up to the disc height and pull the tripods out before the material sets around them. It’s best to clean each one straight after use, especially the threaded shaft, and keep it lubricated so it keeps turning freely. Stainless steel tripods shrug off corrosion on site better than mild steel ones. You should also check the height range – Metex tripods cover 10mm to 150mm, which handles most domestic and commercial depths. Also, make sure to pick tripods with sturdy legs so nothing topples mid-pour.

Got a job coming up?

If you’re working out what you need for a liquid screed or self-levelling concrete pour, get in touch with the Metex team. We’re available over the phone or email every working day and happy to help.

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What Is Liquid Screed?

Liquid screed is a flowing, self-levelling alternative to traditional sand and cement screed, used to create a smooth, level base for floor finishes such as tiles, wood, and laminate. It is also known as flowing screed, calcium sulphate screed, or anhydrite screed, and it has become the standard choice for floors with underfloor heating.

How is liquid screed different from traditional screed?

Liquid screed is pumped into place as a free-flowing liquid rather than laid by hand with a trowel. It self-levels as it is poured (although it does still need guiding and dappling for a smooth finish), needs less labour to install, and can be laid thinner than sand and cement screed because of its higher density and lower void content.

What are the main benefits of liquid screed?

  • Walkable within 24 to 48 hours of being poured
  • Low shrinkage and minimal thermal expansion, which reduces the risk of cracking once the floor is finished
  • Thinner than traditional sand and cement screed, which can mean a useful weight saving on suspended floors
  • Protein-free, so it can’t harbour bacteria, a feature several manufacturers highlight for hygiene-sensitive environments
  • Higher thermal conductivity than sand and cement screed, making it well suited to underfloor heating

How long does liquid screed take to dry?

As a guide, liquid screed dries at a rate of around 1mm per day up to a depth of 40mm under normal conditions. Where the programme needs it, anhydrite (calcium sulphate) screed can be force dried by commissioning the underfloor heating system from 7 days after it has been laid. The typical sequence is:

  • Days 1 to 7: leave to cure at ambient temperature
  • Day 7 onwards: start UFH at a flow temperature of 25 degrees C for the first three days
  • Increase in stages up to a maximum of 55 degrees C

Always check the manufacturer’s own guidance for the specific product before force drying, since timings vary by formulation and depth.

Does liquid screed expand and contract with heat?

All screeds expand slightly as they heat up and dry out, which is why expansion joints are used around the edges of a pour and at junctions between rooms. Anhydrite screed has a low rate of thermal expansion compared to many traditional materials, typically around 0.012mm/mK, though the exact figure varies by product. Always check the data sheet for the specific screed you are using rather than relying on a general figure.

Is there a British Standard for liquid screed?

Yes. Pumpable, self-smoothing screeds in the UK, including both cement-based and calcium sulphate (anhydrite) types, are covered by BS 8204-7, which sets out recommendations for materials, design, site work, and testing.

What Is Self-Levelling Concrete?

Self-levelling concrete is a polymer-modified form of concrete with high flow characteristics, used to create a flat, smooth surface ready for floor coverings. Unlike traditional concrete, it does not need large volumes of water added to make it workable, and it self-levels once poured rather than needing to be screeded by hand.

How does self-levelling concrete compare to traditional concrete?

Self-levelling concrete typically achieves a compressive strength similar to or higher than traditional concrete, while offering a far flatter and smoother finish straight off the pour. This has made it increasingly popular as floor coverings have moved towards thinner vinyl and larger format tiles, both of which show up subfloor imperfections more readily.

How is self-levelling concrete applied?

  • The mixed concrete is poured or pumped into the area to be levelled
  • A gauge rake is used to move the material into place at a consistent depth without spreading it too thin
  • Surface tension is broken using a finishing tool such as a Dapple Bar, to release trapped air and leave a smooth finish
  • The mix is left to level and cure, with the polymers in the formulation keeping the aggregate evenly suspended rather than sinking as it sets

Demand for flatter, smoother subfloors has grown as flooring products have changed. Thinner vinyl and larger format tiles both need a more even base than older floor coverings did, and self-levelling concrete delivers that flatness without the manual raking and trowelling that traditional concrete requires.

What Is a Screed Tripod and How Do You Use One?

A screed tripod, sometimes called a screed spider, is a three-legged, height-adjustable tool used to set the exact level a floor needs to be poured to before liquid screed or self-levelling concrete goes down. Each tripod has a central threaded shaft with a circular disc that can be raised or lowered to match a laser level, giving installers a fixed, visible reference point across the whole floor.

How do you set up screed tripods on site?

  • Establish the datum level. This is the finished floor level you are working to, usually taken from a fixed point such as a door sill. Place the first tripod at this point and adjust its disc to match the datum using a laser level.
  • Position additional tripods across the area to be screeded. A spacing of around 1,500mm between tripods is a good standard for most domestic and commercial pours.
  • Set the laser level to the datum tripod, then transfer that same level across to every other tripod disc in turn, adjusting each one until they all match.
  • Pour the liquid screed or self-levelling concrete up to the height of the tripod discs, checking for high or low patches between tripods as you go.
  • Remove all tripods from the floor once the pour is finished, before the material begins to set around them.

How do you look after screed tripods after use?

Clean each tripod immediately after removing it from the floor, before any screed has the chance to set on it. Pay particular attention to the threaded shaft, since dried screed here will make the disc harder to adjust next time. Lubricating the thread periodically will keep tripods working smoothly over many pours.

What should I look for when buying screed tripods?

Not all screed tripods are built to the same standard. Key things to look for:

  • Fully stainless steel construction. Stainless resists corrosion and lasts far longer on site than mild steel alternatives, particularly when exposed to the alkaline environment of fresh screed.
  • A good height adjustment range. Metex screed tripods handle depths from 10mm to 150mm, covering most domestic and commercial screed depths without needing separate sets of tripods for different jobs.
  • Stable, thicker legs. A tripod that topples mid-pour can ruin a section of an otherwise level floor. Look for legs with enough weight and spread to stay upright in a flowing material.

Metex supply both stainless steel and zinc-plated mild steel screed tripods, alongside the full range of screed and flooring tools available at metextools.com.

Frequently Asked Questions

A screed tripod, sometimes called a screed spider or screedpod, is a three-legged height-adjustable tool used to set the finished floor level before liquid screed or self-compacting concrete is poured. Each tripod has a central threaded shaft with a flat disc that can be raised or lowered to a precise height. The screed is poured up to the level of the disc, giving the installer a consistent reference point across the whole floor without needing to gauge depth by eye.

The number depends on the size of the area being poured, but as a general guide tripods should be positioned at approximately 1,500mm centres across the floor. This gives enough reference points to pour and check levels accurately between them without overcrowding the working area. On larger commercial pours more tripods are needed to maintain consistent coverage; on smaller domestic pours a set of 20 is typically enough to handle most room sizes comfortably.

Start by establishing the datum level, which is the finished floor height you are working to, usually taken from a fixed reference point such as a door threshold or a mark on the wall. Set the first tripod to match this datum, then use a laser level to transfer the same height to every other tripod in turn, adjusting each disc up or down on its threaded shaft until it matches. Once all tripods are set, the laser level provides a continuous check as the pour progresses.

Tripods should be removed once the pour is complete and the screed has reached the level of the discs, but before the material begins to set around them. Leaving them in too long means they become embedded and difficult to remove cleanly, leaving voids or raised marks in the surface.

Stainless steel tripods resist corrosion and last significantly longer on site, particularly in the alkaline environment of fresh screed which is corrosive to mild steel over time. Zinc-plated mild steel tripods cost less upfront but will show signs of corrosion sooner, particularly if not cleaned thoroughly after every use. For contractors laying screed regularly, stainless steel is the more cost-effective choice over the life of the tool. For occasional use or where budget is the primary consideration, zinc-plated tripods are a practical option.

Yes. The same tripod setup process applies to self-compacting concrete as to liquid screed, since both materials are poured to a level set by the tripod discs rather than being hand-screeded to a line. The main practical difference is that self-compacting concrete is heavier and more viscous than liquid screed, so tripods need to be stable enough not to be displaced during the pour. Stainless steel tripods with thick, well-spread legs handle this more reliably than lighter alternatives.

Get in Touch

If you have a question about liquid screed, self-levelling concrete, or using screed tripods on site, get in touch with the Metex team. We are always happy to talk through the details of a job.

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