MLCP pipe for underfloor heating
Updated: 23 October 2026
You are about to cover a coil with screed, and the reel in the hall is either far too short or longer than the room. MLCP pipe for underfloor heating, in this amazon.co.uk set, starts as 16 × 2 mm pipe with an aluminium oxygen barrier and a length that can finish the loop without a joint in the screed. A 25 m coil is a short circuit. A supplier's 100 m figure is a cap those suppliers print, not a clause in the Building Regulations. The seven coils are on the [MLCP pipe comparison](/hub/diy-supplies/mlcp-pipe). Prices are the 19 October 2026 capture. A purchase through our links can earn a commission at no extra cost to you.
You are about to cover a coil with screed, and the reel in the hall is either far too short or longer than the room.
You are about to cover a coil with screed, and the reel in the hall is either far too short or longer than the room. MLCP pipe for underfloor heating, in this amazon.co.uk set, starts as 16 × 2 mm pipe with an aluminium oxygen barrier and a length that can finish the loop without a joint in the screed. A 25 m coil is a short circuit. A supplier's 100 m figure is a cap those suppliers print, not a clause in the Building Regulations. The seven coils are on the MLCP pipe comparison. Prices are the 19 October 2026 capture. A purchase through our links can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Coil length | Size stated | Oxygen barrier | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Adept Adept 16 × 2 mm PERT-AL-PERT, 50 m | 50 m | 16 × 2 mm | Aluminium core | 7.4 | about £64.99 | View offer |
| Alternative |  Adept Adept 16 × 2 mm PERT-AL-PERT, 25 m | 25 m | 16 × 2 mm | Aluminium core | 6.3 | about £36.99 | View offer |
| Best value |  Wärmer System Wärmer System 16 mm PERT-AL-PERT, 100 m | 100 m | 16 mm × 2 mm | Named in the title | 6.7 | about £74.99 | View offer |
On this page
Why the floor coil is usually 16 × 2 mm with a barrier
BEAMA's underfloor-heating pipe guide expects an oxygen barrier, because oxygen in the heating water feeds corrosion in the steel parts of the system. On multilayer pipe the barrier is the aluminium. On PE-X it is often a chemical layer such as EVOH. The Adept 16 mm bullets describe an aluminium core as stopping oxygen ingress. The Wärmer title names an aluminium oxygen barrier, while the material field only says polyethylene. You can read the barrier claim. You cannot treat the material line as a second confirmation.
Sixteen millimetres outside diameter with a 2 mm wall is the size these floor listings print. This set has no 12 mm overlay pipe. A 20 mm, 25 mm, or 32 mm coil is a distribution size, not the default loop. Wholesome-water approval stays on the buying guide.
Spacing is a heat-loss decision
Uponor's solid-screed instructions, for Uponor's own system, say 16 mm pipe is generally at 200 mm centres in a well-insulated building, kept about 100 mm off the wall, and not pulled so tight that the bend kinks. The quantity table prints 5.0 m of pipe per square metre at 200 mm centres and 10.0 m per square metre at 100 mm centres. Floor Heating Warehouse uses 200 mm when the house meets current insulation and the flow is at least about 50°C, and says spacing closes up for heat pumps and for poor insulation. Neither guide is a heat-loss calculation for your room.
A 12 m² room at 5.0 m per square metre is about 60 m of pipe before extra manifold runs. At 100 mm centres the same table is about 120 m, already past a 100 m circuit cap. None of the seven listings prints a heat output. If the insulation is unknown, get a design rather than a rule of thumb.
One loop, no joint in the screed
Uheat sets that firm's maximum circuit at 100 m and says there should be no joints in the screeded area. Floor Heating Warehouse uses 100 m as well, and includes the runs to the manifold. Underfloor Heating Systems Ltd prints 110 m. Do not average 100 m and 110 m into one national rule. The walk from the manifold is part of the circuit, and it is not heating the middle of the room.
The Adept 25 m reel, about £36.99, is a repair or a very small circuit. The Adept 50 m reel, about £64.99, can be one short loop. It cannot be a 100 m circuit. The Wärmer 100 m reel, about £74.99, is the only coil here that matches a 100 m supplier cap in one length. It has no WRAS line and no printed temperature. Joining two 50 m coils under the screed is the joint those pages tell you not to bury. A crease on the turn is repaired on the how to install page.
What to do before the screed is poured
Fix the pipe at the centres the design uses, keep the bend at the edge open enough that the aluminium does not fold, and pressure-test before the screed arrives. The test pressure is the one your manifold sheet prints. This page will not turn a reference to BS EN 806-4, a 3 bar screed note, and a 6 bar, 24-hour note into one UK law. Test first, then cover.
Uponor specifies a minimum of 65 mm of sand-and-cement screed over the insulation in domestic work where it cites British Standards, and treats liquid screed separately, with a cover in the order of 30 mm over the pipe. That is Uponor's instruction for Uponor's system. Follow the floor system you are using, including a slow first heat-up. Once the screed is down, the coil length is no longer a basket edit.
Common questions
Is 16 mm the pipe for a screeded floor?
In this set, 16 × 2 mm is the size the floor coils are sold as, and BEAMA treats the aluminium as the oxygen barrier on multilayer pipe. There is no 12 mm overlay pipe among the seven. A 20 mm or 32 mm coil is a different run. Sixteen millimetres is the usual screed loop here when the manifold is built for it. It is still the wrong pipe if your drawing names another diameter.
How long can one loop be?
Use the cap your supplier prints, and include the pipe from the manifold. Uheat and Floor Heating Warehouse both use 100 m. Underfloor Heating Systems Ltd prints 110 m. Those figures are not a national maximum, and they should not be averaged. A loop longer than the cap you were given needs another port, not a hopeful extra ten metres.
How many metres do I need at 200 mm spacing?
Uponor's table for its own 16 mm system prints 5.0 m of pipe per square metre at 200 mm centres, and 10.0 m at 100 mm. A 12 m² room at 5.0 m per square metre is about 60 m before extra manifold tails if those tails are not already inside the 60 m. Floor Heating Warehouse's sketch of about 100 m for 20 m² is the same sort of guide. It is not a heat-loss calculation, and closer centres use more pipe.
Can I join the pipe under the screed?
Uheat says no joints in the screeded area. A joint you cannot see is a leak you cannot reach without breaking the floor. Buy a coil that finishes the loop, or add a manifold port and a second loop. The 25 m and 50 m reels in this set are shorter than a 100 m cap. Extending them with a buried coupling is the mistake the screed pages are written to prevent.
Why does the pipe need an oxygen barrier?
BEAMA expects a barrier so oxygen does not keep entering the heating water and corroding steel elsewhere in the system. On MLCP the barrier is the aluminium. On many PE-X floor pipes it is a chemical layer such as EVOH. A pipe with neither is the one to refuse on a sealed heating system. Read the listing: a title that names aluminium is not the same as a material field that only says polyethylene.
Is a 25 m coil enough?
Only for a very small circuit or a repair. The Adept 25 m coil of 16 × 2 mm is the shortest 16 mm reel here. A normal room at 200 mm centres uses several times that once the manifold runs are included. The 50 m coil can be one short loop. The 100 m Wärmer coil is the one that matches a 100 m supplier cap in a single length, with the paperwork limits already noted.
Related pages
Sources
Public UK sources listed below, plus the seven amazon.co.uk listings compared on this page. Listings captured 19 October 2026. Updated 23 October 2026.
- Water Supply (Water Fittings) Regulations 1999 (retrieved 23 October 2026)
- WRAS appropriate standards (retrieved 23 October 2026)
- Water Regs UK, BS 6920 note (April 2025) (retrieved 23 October 2026)
- Approved Document G (retrieved 23 October 2026)
- Approved Document L Volume 1 (2021, 2023 amendments) (retrieved 23 October 2026)
- BEAMA underfloor heating pipe guide (retrieved 23 October 2026)
- Uponor UK multilayer specification (retrieved 23 October 2026)
- ISO 21003-2:2008 (retrieved 23 October 2026)