Vapour barrier tape buying guide
Updated: October 2026
You are in a loft with a polythene sheet, a staple gun, and a search page that mixes silver duct tape with a roll that actually says vapour barrier. This vapour barrier tape buying guide is the checklist before you open the [vapour barrier tape comparison](/hub/site-barriers/vapour-barrier-tape). The Products Compared editorial team read four amazon.co.uk listings on 16 October 2026, plus public notes from Novia, A. Proctor Group and DuPont. We did not run a lab peel test. A qualifying purchase can earn a commission at no extra cost to you.
You are in a loft with a polythene sheet, a staple gun, and a search page that mixes silver duct tape with a roll that actually says vapour barrier.
You are in a loft with a polythene sheet, a staple gun, and a search page that mixes silver duct tape with a roll that actually says vapour barrier. This vapour barrier tape buying guide is the checklist before you open the vapour barrier tape comparison. The Products Compared editorial team read four amazon.co.uk listings on 16 October 2026, plus public notes from Novia, A. Proctor Group and DuPont. We did not run a lab peel test. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Width | Roll length | Hand tear | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  tesa tesa 60077, 50 mm | 50 mm | 25 m | n/a | 8.2 | about £30.84 | View offer |
 DuPont Tyvek AirGuard 1310V, 60 mm | 60 mm | 25 m | Yes | 8.6 | about £28.00 | View offer | |
| Best value |  Ealyder Ealyder polyethylene, 100 mm | 100 mm | 54.8 m | n/a | 6.8 | about £17.99 | View offer |
On this page
Match the sheet before the roll
The sheet is the vapour control layer. Approved Document C, England's guidance for Requirement C2, asks the building to resist condensation and defines that layer. It does not approve a brand of tape. The practical split still travels: an internal air and vapour control layer sits on the warm side of the insulation, and a breather membrane sits on the cold side. Tape written for one face is a poor guess for the other.
DuPont's UK data sheet for AirGuard tape 1310V recommends internal use with AirGuard AVCLs. If your membrane maker publishes a tape list, start there. A title that mentions a house envelope has not earned the same job. UK reviews on the red XFasten roll say it failed on an exterior vapour barrier and left a breathable membrane overnight. Brick is not your polythene lap. The foil tape page separates the HVAC aisle from this one.
Butyl in the lap, single-sided over it
Novia's guidance asks for a 150 mm lap, butyl at least 30 mm wide inside the joint, and a single-sided cover tape over the top. Staples go through the butyl, so the gasket is behind the hole. A face tape does not reach that hole from behind. If you staple through bare polythene and only buy the green or white roll, you have closed the overlap you can see and left a row of pinholes.
None of the four rolls in this comparison is sold as double-sided butyl. You still need butyl, or the maker's double-sided tape, wherever staples puncture the sheet. Order the gasket before you board. Pressure and pipes are on the how to tape a vapour barrier page.
Width, length and the day you stick it
Width follows the lap. Novia's 150 mm figure is the sheet overlap, not the tape. A 50 mm or 60 mm strip can sit in the middle of that overlap if the sheets lie flat. Wider is not a better seal if you cannot press both edges.
Shelf prices on 16 October 2026 were £28.00 for 25 m of Tyvek, £30.84 for 25 m of tesa, £17.99 for 54.8 m of Ealyder, and £11.99 for about 55 m of XFasten. The long roll saves money only if it is still stuck after the plasterboard goes on.
What these four listings can and cannot tell you
The comparison ranks these rolls. This guide only says what each listing can prove. Tyvek's stored reviews are marked United Kingdom and buyers describe a membrane. tesa's star line is higher, and the stored review text is not marked United Kingdom. Ealyder's UK file includes lift-off. XFasten's UK reviews report release from membrane. None of them is BS 5250 certified. If you want one internal roll and one longer roll named with their limits, use the best vapour barrier tape page.
What to decide before you buy
If the membrane maker names a tape, start there. If staples puncture the sheet, buy butyl as well as a single-sided cover. If the lap is flat, 50 mm or 60 mm can sit on a 150 mm overlap. If you cannot press both edges, do not buy width you will not stick. A longer cheap roll is a saving only after a test strip is still there in the morning.
Common questions
Is 50 mm wide enough if the lap is 150 mm?
Yes, if the 150 mm is the sheet overlap and the tape sits on a flat joint. Novia specifies that lap and then a cover tape, not a tape that is itself 150 mm wide. tesa's roll is 50 mm and Tyvek's is 60 mm. A 100 mm roll covers more wrinkles and is harder around a pipe. If the sheets are dusty or the joint is in tension, width will not save it.
Do I need double-sided butyl as well as this roll?
You need it where staples go through the sheet. Novia puts butyl at least 30 mm wide in the lap and staples through that gasket, then adds a single-sided cover tape. None of the four amazon.co.uk rolls here is sold as that butyl. A face tape hides the staple and does not seal the hole from behind. Skip the extra roll only if your fixing does not puncture the AVCL.
Is a 100 mm roll better because it covers more?
It covers more of a wrinkled overlap. It is not automatically a better seal. Ealyder is 100 mm by 54.8 m at £17.99, and UK reviews in that file include next-day lift when the membrane flexed or sat under cladding. Press both edges. If you cannot, the extra width is unused adhesive.
Why is the long roll so much cheaper per metre?
You are paying for more length at a lower shelf price, not for a second test report. Ealyder is about £0.33 a metre and XFasten about £0.22, against roughly £1.12 to £1.23 for the 25 m rolls, as a rule of thumb on these prices. The saving holds only if the tape stays stuck after the boards go on. Read the UK lift-off notes before you buy length as a substitute for a matched tape.
What temperature should the loft be when I stick it?
A. Proctor Group's window for its AVCL tapes is about 5°C to 30°C, on a clean dry surface, with a roller at reveals. DuPont's install note for 1310V is above −5°C, so use the figure for the roll in your hand. A loft that feels merely cool can still be under 5°C at the sheet. Warm the roll indoors, and do not stick onto a damp or dusty surface.
Related pages
Sources
Public UK sources from the research digest. Listing prices, stars, and review counts are the amazon.co.uk lines stored with these four ASINs. Page updated October 2026.
- Approved Document C — Requirement C2 and the vapour control layer (retrieved October 2026)
- BSI BS 5250:2021 — Management of moisture in buildings (retrieved October 2026)
- IKO note on BS 5250:2021 (retrieved October 2026)
- A. Proctor Group — installing air and vapour control layers (retrieved October 2026)
- Novia vapour control layers (retrieved October 2026)
- DuPont UK TDS, AirGuard tape 1310V (retrieved October 2026)
- tesa UK 60077 note (retrieved October 2026)
- Passivhaus Trust airtightness guide, June 2020 (retrieved October 2026)