Vapour barrier thickness

[dhutch]

Im considering installing a vapour barrier in the 1st floor ceilings of my house to target dampness on the underside of the floorboards in my unheated attic as I will be skimming the ceilings anyway so reboarding is not much of an issue or cost.

Presumably almost any thickness of polythene will do the job? I have considered foil backed plasterboard but if nothing else stapling up some left over poly sheet ive got in the garage will allow me to do a bit of a test in advance of doing the plasterboard.


Daniel

 

[Deluks]

Just remember to tape all seams with pvc tape.

http://www.wickes.co.uk/polythene-vapour-barrier-25mx20m/invt/153230/?source=123_74 for the real stuff.

 

[dhutch]

Just remember to tape all seams with pvc tape

Yes I will do, although it will be well sandwiched and proberbly with a good overlap.

The stuff I have is more like this if not the self same:
http://www.diy.com/nav/build/buildi...ral-Purpose-Cover-Sheet-Clear-3m-x-4m-9273084


Daniel

 

[Deluks]

Probably slightly thinner than the proper stuff. However no one will be inspecting it so up to you.

You might well find that the dampness shows up elsewhere as you'll be trapping it in the room, take usual precautions against condensation.
Have a read through all the 'damp' topics that have come up on here in the last few weeks.

 

[dhutch]

Probably slightly thinner than the proper stuff. However no one will be inspecting it so up to you.

Yeah, i was just wondering how much it mattered in terms of the actaull functionality, I guess what I would need to know is the permibility of LDPE of the thickness, as its not stated on it becauses its not sold for that purpose.

I think I will put it up and see if it stops it coming through, assuming it does, replace it with the correct stuff or use foilbacked plasterboard.

As you say, I then separatly need to take steps to increase ventilation in the house.


Daniel

 

[theoldun]

The stuff I have is more like this if not the self same:
http://www.diy.com/nav/build/buildi...ral-Purpose-Cover-Sheet-Clear-3m-x-4m-9273084

The above is not fit for your purpose. Go with what the Duke has said.
Regards oldun

 

[dhutch]

The above is not fit for your purpose. Go with what the Duke has said.
Regards oldun

Fair enough, no point in pitching for a penny of tar really.

On another topic, anyone had any experience of paint-on vapour barriers? one room has already been skimed, but was not overboarded and hence it would be advantagious to be able to add some vapour control retrospectivly, espically as the room is rented out to a lodger.

I have found
- Gyproc Drywall Sealer 10L £40 for 10l 70m^2 (60pence/m^2)
- or Zinsser BIN 1l £37 2.5l 31m^2 (£1.20/m^2) but the room is ofcause only about 10m^2


Daniel