Vapour Barrier Paint (loft condensation)

[heating12numpty12]

I have condensation occurring in a roof space, the root cause of the problem is that the builder didn't fit a vapour barrier on the inside of the roof/ceiling (which the specification called for).

I have been made aware that there are vapour barrier paints on the market (used a lot in Canada). Vapor Barrier Interior Primer Sealer 1060-1200 Previously ICI Paints PREP & PRIME™ VAPOR BARRIER, but unable to obtain a source in the UK.

https://www.gliddenprofessional.com/datasheets/tds/gp-1060.aspx

Does anyone know of a UK brand?

I am taking additional measures to cure the problem, i.e the fitting of vented ridge tiles.

 

[freddiemercurystwin]

Assuming you are talking about above a ceiling beneath a ventilated loft I would be hesitant to blame condensation on a lack of a vapour barrier, millions of properties throughout the UK do not have a a VB yet do not have condensation problems. Condensation occurring in a loft is usually due to a lack of ventilation. Where would you apply a VB anyway - on the top of the plasterboard? Or the underside? There is a clear VB on the market in the UK.

 

[JohnD]

have a look at
//www.diynot.com/diy/threads/condensation-in-loft-answers.160032/

 

[heating12numpty12]

Assuming you are talking about above a ceiling beneath a ventilated loft I would be hesitant to blame condensation on a lack of a vapour barrier, millions of properties throughout the UK do not have a a VB yet do not have condensation problems. Condensation occurring in a loft is usually due to a lack of ventilation. Where would you apply a VB anyway - on the top of the plasterboard? Or the underside? There is a clear VB on the market in the UK.

Yes the paint would be applied to the inside ceiling.

I have spoken to roofers who have advised that vented ridge tiles may help in solving the problem, but no guarantees. So looking at additional measures to help in solving the problem.

PS, the spec for the build did call up a Vapour Barrier.

You say "There is a clear VB on the market in the UK." could you advise on this.

 

[freddiemercurystwin]

Yes well as mentioned I would question the need for a VB here and would be increasing ventilation myself - which seems perfectly adequate for millions of properties throughout the UK. Anyway there are several, RIW http://www.riw.co.uk/products/liquid-applied-systems/flexiseal-pro which is black as night or Permagaurd https://www.permagard.co.uk/damp-proofing/paint/damp-proof-paint or a clear one https://www.restorationuk.com/damp-...-39-epoxy-resin-concrete-sealer-floor-coating - Restoration UK also do a white one https://www.restorationuk.com/damp-...nal-walls/product/ruk-lvm-waterproofing-paint

Sika may also do one , there are probably others.

 

[John D v2.0]

The plasterboard should be a reasonable barrier if intact. We had the same in our spec but the builder skimmed the ceiling which is OK. The poly sheet would have been better belly and braces.
The big problem would be either excessive humidity in the room below, or gaps in the ceiling eg cracks or holes. Check especially above the light fitting where the cables pass through, but even through sockets and switches if the plasterboard is open to the roof space.
You can seal most of these places well enough and cheaply with acrylic sealant.

 

[heating12numpty12]

We have 8 LED down lights and 2 detectors (smoke, CO2) which are a major source of warm air going into the loft space.

 

[John D v2.0]

OK that would be your problem then, try to find a way to stop that. One would be to have a double layer ceiling and don't make holes in the top ( insulated) one

 

[JohnD]

We have 8 LED down lights and 2 detectors (smoke, CO2) which are a major source of warm air going into the loft space.

if you have holes in the ceiling, vapour paint is irrelevant.

the root cause of the problem is that the builder didn't fit a vapour barrier on the inside of the roof/ceiling

nope.