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Best vapour barrier

Updated: 21 October 2026

You want one sheet for a garden-room frame, and the stars pull in two directions. The best vapour barrier in this set is the full roll that states 500 gauge and EN 13984, with a width check on arrival. Peter F. compared the five amazon.co.uk listings. Prices are the GBP shelf prices, and the scores are editorial sums, not a lab test. A qualifying purchase can earn a commission at no extra cost to you. See the [vapour barrier comparison](/hub/flooring-tools-and-accessories/vapour-barrier). Gauge and width, before stars, are on the [vapour barrier buying guide](/hub/flooring-tools-and-accessories/vapour-barrier/sub/vapour-barrier-buying-guide).

You want one sheet for a garden-room frame, and the stars pull in two directions. The best vapour barrier in this set is the full roll that states 500 gauge and EN 13984, with a width check on arrival. Peter F.

Our top picks

ndcpolipak ndcpolipak 500 gauge, 2.7 m x 50 m

Best overall

ndcpolipak ndcpolipak 500 gauge, 2.7 m x 50 m
8.0/10about £63.69
View offer
Just The Job Supplies Ltd Just The Job GVC2, 2.5 m x 5 m

Best value

Just The Job Supplies Ltd Just The Job GVC2, 2.5 m x 5 m
7.0/10about £12.60
View offer
Just The Job Supplies Ltd Just The Job GVC4, 4 m x 5 m

Alternative

Just The Job Supplies Ltd Just The Job GVC4, 4 m x 5 m
6.2/10about £15.69
View offer
On this page
  1. 1.What best means in this set
  2. 2.The full 500 gauge roll
  3. 3.The short green cuts
  4. 4.The yellow sheet and the sauna foil

What best means in this set

Best, here, means a stated warm-side thickness, a named product standard, and a review sample large enough to mention faults. The NHBC 2025 extract for external timber-framed walls sets a minimum of 500 gauge on the warm side. LABC Warranty accepts 125 micron polythene as one form of that layer. EN 13984 is the standard a maker names for a vapour control layer. The row that meets the three tests is ndcpolipak B084FM2VF2.

The full 500 gauge roll

B084FM2VF2 is listed at £63.69 as green polythene, 500 gauge and 125MU, titled 2.7 m by 50 m. The bullets say CE marked to EN 13984 and use the name Damplas for walls, roofs and floors. It is 4.6 from 97 reviews, and it is the top pick because it is the only full roll that names both the gauge and EN 13984. It is not a sheet we measured. One verified UK review says the sheet was 2.45 m wide. Another reports holes at the folds. Measure the first metre before you staple. Skip this roll for a few square metres, a stated 1200 gauge damp-proof membrane, or a sauna.
ndcpolipak ndcpolipak 500 gauge, 2.7 m x 50 m

Testsieger

ndcpolipak ndcpolipak 500 gauge, 2.7 m x 50 m
8.0/10about £63.69
View offer

The short green cuts

Just The Job GVC2, B0DTKQ7FW2, is the best value only as a small stated 125 micron cut, listed at £12.60. The title says 2.5 m by 5 m, the dimension line can be read as 10 m by 2.5 m, and there is no EN 13984 line. Buy it for a small patch you will measure. GVC4, B0DLBDRDXV, is the wider short cut at £15.69, titled 4 m wide and 5 metres, with only two short United Kingdom texts. The dimension line is 1 by 400 by 0.01 cm, so the 4 m width is there and the 5 m length is not.

The yellow sheet and the sauna foil

The B2C yellow sheet, B0FZL66X8N, is listed at £19.79 as polyethylene, 0.2 mm, with a tolerance of ±30%. The coverage field says 20 m², while the title also says 2 m by 50 m. It is 5.0 from two ratings. Two reviews cannot outvote 97. The bullets name concrete and screeds. That floor is on the vapour barrier under laminate page. The B2C foil, B0H717S9WR, at £42.25, is a sauna facing, not a 500 gauge roll. If the moisture is from the ground, none of these five is a stated 1200 gauge membrane. That split is on the vapour barrier vs damp proof membrane page.

Common questions

Which listing should I start with for a timber frame?
Start with ndcpolipak B084FM2VF2, at £63.69, when you want a full roll that states 500 gauge and EN 13984. The rating is 4.6 from 97 reviews, the largest sample here. One verified review says the width was 2.45 m, and another reports holes at the folds, so measure before you fix the layout. It is the top pick on those listing facts, not because we tested the plastic.
Is the cheapest sheet a false economy?
It is, when you needed 50 m and a named standard. At £12.60, GVC2 is the lowest shelf price and it does state 125 micron. The dimension line clashes with the 5 m title, two reviews say it arrived folded, and EN 13984 is absent. For one small wall you can measure, the price matches the job. For a whole garden room it does not.
Does 5.0 from two reviews beat 4.6 from 97?
No. The yellow sheet is 5.0 from two ratings. The ndcpolipak roll is 4.6 from 97. The larger sample is the one that records a 2.45 m width and holes at the folds. Two warm sentences cannot describe a storey-height drop. Read the stars as a sample size, after the gauge and the standard line.
Is the £42 foil a better membrane because it costs more?
No. B0H717S9WR is aluminium foil and kraft for sauna walls and ceilings, 30 m², with no review line in this file. The vapour-resistance figure of 2748 m has no test method on the listing. The extra pounds buy a different product. They do not buy a thicker green vapour control layer or the polyethylene Approved Document C describes under a slab.
What if the 2.7 m roll arrives nearer 2.45 m?
Measure it and reset the laps. One verified review of B084FM2VF2 says 2.45 m, and UK merchants sell 125 micron green at 2.45 m by 50 m, so the figure can be a real cut. A layout drawn for 2.7 m will be short at the head or the base. If the goods do not match the title, the Consumer Rights Act 2015 is the route.
Who should not buy any of these five?
Skip the set if you need a stated 1200 gauge damp-proof membrane, a radon barrier, a measured sd-value for a laminate maker, or a sheet we have tested in a lab. None of the five is a 300 micrometre membrane under a slab. If the job is outside a simple warm-side frame, take the specification to someone who designs that element.

Related pages

How to fit a vapour control layer

Vapour barrier

Vapour barrier buying guide: gauge before the stars

Vapour barrier under laminate: film, not a wall roll

Vapour barrier or a damp-proof membrane: the split

Sources

Public UK sources used for this comparison. Listing prices, stars and review counts are the amazon.co.uk lines kept with these five products. Shelf date 19 October 2026.

  1. Approved Document C, 2013 (retrieved October 2026)
  2. Approved Document L Volume 1 (retrieved October 2026)
  3. LABC Warranty vapour control layers (retrieved October 2026)
  4. NHBC 7.2.15 pitched roofs (retrieved October 2026)
  5. BS EN 13984:2013 (retrieved October 2026)
  6. NDC Polipak damp proofing (retrieved October 2026)
  7. Wickes Damplas VCL sheet (retrieved October 2026)
  8. Wickes laminate flooring guide (retrieved October 2026)