cheap vapour barrier sheeting

[george [dicegeorge]]

I have stone walls with lime mortar, then wooden battens and kingspan. Before the plywood/plasterboard I need a vapour barrier.

Would any plastic sheeting do? B&Q advertise General Purpose Sheeting 4 x 25m £19.77

plastic is so common these days there must be a far cheaper source of rolls of plastic sheeting available somewhere, I will need a lot of it if I'm to insualte all the walls ceilings and floors

[g]

[dom]

If the kingspan is continuous, rather than between studs, join sheets with aluminium tape.

Check out Kingspan or Celotex websites for recommended installation practice.

[Dave Liquorice]

Why are your doing *all* walls ceilings and floors? You only need to do those that let heat out of the building, ie external walls, ground floors and top floor ceilings. Ideally the insulation is contiguious across floor voids on the external walls.

I can envisage that a building as a collection of insulated boxes won't be very comfortable, some rooms willl be too hot from the waste heat that can't "escape" to cooler rooms and some rooms will be too cold has they don't benefit from the heat of other rooms...

[george [dicegeorge]]

yes , i meant to say all the external walls, floors and ceilings (it make take a few decades though) [g]

[g]

[george [dicegeorge]]

£19.77> but plastic is so common these days there must be a far cheaper source

The kingspan is between studs, and as its seconds and thirds it has gaps filled with foam which may or may not be permeable to water vapour. Perhaps a thin layer of insulation as vapour barrier, but this could be very expensive. Dunno - that's why i'm asking for advice and ideas.

[g]

[Tabby]

Plastic film lets a fair bit of water vapour through. Better to go for value aluminium foil. PVA sticks it well. Another option is bitumen paint.

NT

[Andrew Mawson]

kingspan.

but plastic is so common these days there must be a far cheaper source

That's exactly what I used on my timber wood work shop. 4x2 construction, breathable roofing sarking under the outside 6x1 timber cladding, rockwool infill, and that Screwfix plastic sheeting under the 18mm osb inside wall claddding. It's been ok so far (2 years)

AWEM

[george [dicegeorge]]

How do you know it's been OK? If there was condensation it would slowly rot the wood nvisibly over many years wouldnt it? (I have no experience of this, I'm working from first principles - but I've seen rotten wood in this house and caravans) [g]

[The Natural Philosopher]

£19.77

tape more al foil over it, or use foil backed PB to finish.

[george [dicegeorge]]

£19.77> but plastic is so common these days there must be a far cheaper source

uh oh -plastic film lets through vapour... there are thousands of different plastics - what words am I searching for?

So the B&Q general purpose plastic sheeting

not be good enough?

But their green vapour barrier may be [

No. BQ 12869

50m². Polythene offers high resistance to the flow of water vapour. ]

The first wall is 2.8 meters high so as this product is 2.5m wide I'd need huge amounts of expensive tape for the joints, or maybe a glue?

I dont want to spend money for somethnig which wont work in the long term. [g]

[Jules Richardson]

using .004" stuff, but I don't think I'd risk anything thinner - too much risk of it being damaged or punctured while I was being put up.