Best Screed for Underfloor Heating in 2025 Explained

09th April 2025

If you're planning to install underfloor heating, don’t let the screed choice be an afterthought. The right screed helps your heating system run efficiently, warms the room faster, and protects your floor finish for years to come. The wrong one? That could mean longer heat-up times, poor energy performance, or even costly cracking down the line.

In 2025, liquid screed remains a top performer for speed and thermal output, but it’s not always the best fit. Your choice of screed – fast-drying or traditional – depends on your timeline, flooring type, and budget.

This guide compares the top screed types for underfloor heating. It shows the main benefits, trade-offs, and installation tips – so you can avoid the guesswork and make the right call.

Key Highlights

Liquid screed offers top thermal performance and faster installations for underfloor heating systems.
Correct screed thickness directly impacts energy efficiency and comfort.
Fast-drying and self-levelling options help meet tight renovation deadlines.

What Is Screed & Why It Matters for Underfloor Heating

Screed is a thin, protective layer that covers your underfloor heating pipes. It acts as the base for your final flooring – whether you choose tiles, vinyl, or engineered timber. However, it’s not just there to make things level. It supports the heating system, brings warmth to the surface, and shields everything below from movement or moisture.

But not all screeds are created equal. Some transfer heat better than others. Some dry quicker. Some are easier to pour into awkward spaces. The wrong screed could leave your floor cold and uneven – or worse, cracked and costly to repair.

In short, your screed choice plays a major role in how your underfloor heating system performs. Let’s look at what to consider when making your decision.

Key Factors to Consider When Choosing Screed for Underfloor Heating

Not sure how to choose between screed types? These four factors will help you match the right mix to your heating system, schedule, and budget.

1. Thermal Conductivity

A screed that conducts heat well will make your underfloor heating more efficient and responsive. Liquid screeds, especially those made with cement, perform best. They fully encase the pipes and can be applied thinner than traditional mixes.

This means heat reaches the surface faster, and your boiler works less to achieve the same cosy result.

2. Drying Time

If you’re working to a tight schedule, drying time matters.

Traditional screeds can take up to 21 days to cure.
Fast-drying and liquid screeds can be walkable in 24–48 hours and accept floor finishes in as little as 7 days.

Selecting a faster-curing screed can help you dodge delays. It also means you won’t have to leap over taped-off zones like it’s an obstacle course.

3. Strength & Durability

Screed doesn’t just carry heat – it also carries the weight of furniture, foot traffic, and the occasional dropped power tool. Cement-based screeds are known for their high compressive strength.

This makes them a solid option for both homes and commercial spaces.

Durability matters most in high-traffic areas and rooms with heavy use, like kitchens, hallways, or offices.

4. Compatibility with Underfloor Heating Systems

Most screeds are compatible with both wet (water-based) and electric systems, but it’s worth checking.

Anhydrite screeds, for example, require sealing before flooring is laid.
Cement-based options are typically more flexible and forgiving in moisture-sensitive areas.

Working with a contractor who knows screed system pairings, like our team, means no surprises after installation.

Screed Types Compared: Which Is Best for Underfloor Heating?

Not all screeds are created equal. Some are built for performance, others for budget, and some just want to dry quickly so the rest of the job can carry on. Let’s break down the top options in 2025 – and when each one makes sense.

Traditional Sand & Cement Screed

The time-tested option. Made from a basic mix of sand, cement, and water, this screed is familiar to most trades and widely used on domestic jobs.

Best for: Smaller projects or when sticking to a budget.
Pros: Readily available, installer-friendly, strong underfoot.
Cons: Slower drying, needs a thicker layer (50–75mm), lower heat conductivity.

Want a reliable, no-fuss solution? Our traditional screed service is ideal for homeowners who value cost and familiarity over speed.

Liquid Screed (Cement-Based or Anhydrite)

Liquid screed is the go-to for modern underfloor heating systems. It flows easily, self-levels, and wraps tightly around pipes for superb heat transfer.

Best for: New builds, large floor areas, energy-conscious homes.
Pros: Higher thermal efficiency, thinner application (30–50mm), faster installation.
Cons: May need sealing (especially anhydrite), not ideal for damp zones without prep.

We use cement-based liquid screeds across the South to help clients save time and boost heating efficiency.

Fast-Drying Screed

In a rush? Fast-drying screeds are modified with additives that speed up curing without compromising performance.

Best for: Renovations or projects with tight timelines.
Pros: Walkable within 1–2 days, quick to receive flooring.
Cons: Typically more expensive, and flexibility varies by product.

These are ideal when other trades are waiting or your flooring delivery is already booked.

Self-Levelling Screed

Self-levelling screed is mainly used as a finishing layer. It creates ultra-smooth, bump-free surfaces for premium flooring.

Best for: High-end finishes like tiles, LVT, or engineered wood.
Pros: Minimal manual labour, flawless finish, great for large areas.
Cons: May need priming, not always suitable as a standalone underfloor heating layer.

This is the cherry on top when a perfectly level finish is non-negotiable.

How Thick Should Screed Be Over Underfloor Heating?

Screed thickness directly affects how well your underfloor heating performs. Too thick, and it slows heat transfer. Too thin, and it won’t protect your pipework, leaving your floor vulnerable to cracking or uneven temperatures.

So, what’s the sweet spot?

Recommended Thickness by Screed Type

The figures below are based on UK industry guidance and typical product specs:

Traditional Screed: 50–75mm
Liquid Screed (Cement-Based): 30–50mm
Fast-Drying Screed: 40–60mm (varies by mix)
Self-Levelling Compounds: 3–10mm (used as a top layer only)

According to NHBC guidance (2023), you must have a minimum of 30mm of coverage over underfloor heating pipes when using liquid screed in residential settings. So, if you're adding to a low-profile floor or want to reduce build-up, a liquid screed can save space and maintain good heat performance.

Need help calculating your ideal thickness? Our team can work with your floor plan to find the proper build-up. Contact us for a no-obligation quote or screed consultation.

Tips for Installing Screed Over Underfloor Heating Systems

Screeding over underfloor heating isn’t just about pouring and hoping for the best. Like brewing a good cup of tea, it takes timing, technique, and the right temperature – rush it, and you’ll regret it later.

Here’s how to get it right, step by step.

1. Prep Before You Pour

Pressure-test your underfloor heating system first – never pour screed over untested pipework.
Install perimeter insulation and expansion joints in large or open-plan areas. These help absorb movement as the screed expands and contracts.
When using anhydrite screed, apply a primer or sealant on moisture-sensitive subfloors to prevent delamination.

Make sure the surface is clean, clear, and ready to receive the mix. Screed needs a good base – no debris, dust, or leftover biscuit wrappers.

2. During Pour: Steady & Accurate

If you’re using liquid screed, let it do what it does best – flow. But it still needs to be guided to ensure even distribution. Our concrete pumping service excels here. We deliver screed cleanly and efficiently, even in tricky or hard-to-reach places.

For traditional or fast-drying screeds, manual levelling and proper compaction are essential. Miss this step, and you risk an uneven floor or poor heat circulation.

3. Let It Cure & Warm It Up Slowly

The biggest mistake? Turning on the heating too soon.

Wait 7–14 days for liquid screed
Wait up to 21 days for traditional mixes
(Always check your product’s data sheet)

Once fully cured, increase the underfloor heating temperature gradually – no more than 5°C per day. This helps the screed adjust without cracking or stressing the pipes.

Patience pays off. Think of it as your floor’s warm-up routine – just don’t expect it to sprint straight out of the gate.

Warm Floors, Solid Finish – Start with the Right Screed

Your underfloor heating system works best when paired with the right screed.

Choosing carefully affects how quickly things heat up, how comfortable your space feels, how much energy you use – and how long your floor lasts. This holds true whether you're building from scratch or just renovating one room.

Here’s What to Remember

Liquid screeds are the best all-rounders for performance and speed.
Traditional screeds remain a solid, budget-friendly option for simpler jobs.
Fast-drying screeds help you stay on schedule when time is tight.
Self-levelling screeds give you the flawless finish your flooring deserves.
Installation technique and thickness matter just as much as the mix itself.

We’ve installed screeds in everything from kitchens to commercial builds, and we’re happy to help you choose what’s right for your setup. Get in touch today for a free quote or expert advice – no pressure, just straight answers.

Call us on 01489 552737 or contact the team online to get started.