How much UFH pipe do I need per square metre?

The amount of pipe depends on your spacing. At 100mm centres, you need 10m of pipe per m². At 150mm centres (the UK standard), you need 6.67m per m². At 200mm centres, you need 5m per m².

What is the maximum length for a UFH loop?

In the UK, the industry standard maximum loop length is 100m to 110m for 16mm pipe. This includes the 'tails' that run back to the manifold. If a loop is too long, the pump may struggle to circulate water effectively, and the room will have cold spots.

What spacing should I use for my UFH?

150mm centres are standard for most well-insulated modern homes. 200mm spacing is sometimes used in hallways or areas with low heat loss. 100mm spacing is used in areas with very high heat loss (like conservatories) or when using low-temperature heat sources like heat pumps.

Do I need to pressure test UFH pipes?

Yes, absolutely. UFH systems must be pressure tested with water (usually to 6 bar) for at least 24 hours before the floor screed is poured. This ensures there are no leaks in the pipes or manifold connections that would be impossible to fix once the concrete has set.

How much UFH pipe do I need per square metre?

The amount of pipe depends on your spacing. At 100mm centres, you need 10m of pipe per m². At 150mm centres (the UK standard), you need 6.67m per m². At 200mm centres, you need 5m per m².

What is the maximum length for a UFH loop?

In the UK, the industry standard maximum loop length is 100m to 110m for 16mm pipe. This includes the 'tails' that run back to the manifold. If a loop is too long, the pump may struggle to circulate water effectively, and the room will have cold spots.

What spacing should I use for my UFH?

150mm centres are standard for most well-insulated modern homes. 200mm spacing is sometimes used in hallways or areas with low heat loss. 100mm spacing is used in areas with very high heat loss (like conservatories) or when using low-temperature heat sources like heat pumps.

Do I need to pressure test UFH pipes?

Yes, absolutely. UFH systems must be pressure tested with water (usually to 6 bar) for at least 24 hours before the floor screed is poured. This ensures there are no leaks in the pipes or manifold connections that would be impossible to fix once the concrete has set.

UFH Pipe Calculator

Layout planning for wet underfloor heating systems.

Floor Area (m²)

Pipe Spacing (Centres)

Distance to Manifold (m)

Pipe Takeoff

Installation Tip: Never have more than **100m** of pipe in a single loop. If the loop is too long, the water will lose too much heat before it returns to the manifold, resulting in an unevenly heated floor.

Invisible Comfort: The Wet UFH Advantage

Radiant Heat

Wet underfloor heating (UFH) turns your entire floor into a giant, low-temperature radiator. It provides a more even heat distribution than traditional radiators and is significantly more efficient when paired with modern condensing boilers or air-source heat pumps.

Our **UFH pipe calculator** helps you plan your manifold requirements and ensure you have enough pipe on site before the screeding team arrives.

Pipe Requirements

100mm Spacing10m per m²

150mm Spacing6.7m per m²

200mm Spacing5.0m per m²

Manifold Placement

The **manifold** is the heart of the system. It should be placed in a central location (like a utility cupboard or under the stairs) to minimize the length of the 'tails' (the pipes that connect the heated area to the manifold).

Every loop of pipe should be a single, continuous run without any joins in the floor. Joins are potential leak points and are strictly forbidden under UK building regulations for screeded floors.

16mm PEX-AL-PEX

Most modern UFH systems use 16mm multi-layer pipe (PEX-AL-PEX). The aluminium core allows the pipe to hold its shape when bent, making installation significantly easier than standard plastic pipe.

Edge Insulation

Always install **perimeter strip insulation** around the edges of the room before laying the pipe and screed. This allows the floor slab to expand and contract as it heats up and cools down without cracking the walls.

Pro Tip: Loop Labels

Label both ends of every loop at the manifold as you install them (e.g., 'Kitchen Loop 1', 'Dining Room'). This will save hours of frustration during the commissioning phase when you are trying to balance the flow rates for each room.

Underfloor Heating FAQ

Project Disclaimer

This calculator is for pipe length estimation only. A full hydraulic design, including manifold flow rates, pump sizing, and heat output verification, should be provided by your UFH supplier or a qualified heating engineer.