Does anyone watch Holmes on Homes. He places plastic sheeting between wooden studs and the drywall on every program. The plastic sheeting is sealed airtight with duct tape. Is this right??? Will this not cause the wall to sweat/trap vapour especially in wet areas. I am asking as the price of a proper vapour barrier is way to expensive and you can pick up cheaps reems of plastic sheeting for £5.
Im confused
- Thread starter Paddie
- Start date
i've not seen the prog or done this particular job.
i do know the experts have conflicting thoughts on the worth of vapour barriers.
what i do know is about damp.
if for example a wall had penetrating damp ie water moving from outside to the inside of the house then a PVC sheet sealed with duct tape would be a way of stopping the damp getting into the house. a lot of houses these days suffer from condensation which escapes to an extent through the brickwork. the addition of the PVC would have the effect of making any condensation worse and potentially trapping moisture coming from outside. the question is whether in reality it's a problem.
the vapour barrier is supposed to sort this potential problem by allowing moisture to move outwards but not inwards from outside.
the verdict i believe is still out. the building regs say use the vapour barrier. if you tape a piece of plastic over a damp wall and leave it for 24hrs then you will definitely find water on the back of the pvc. given this i'm not sold on either. the question is where can this trapped moisture get to if the duct tape fails and what can it damage before natural ventilation can take hold and get rid of it.
in short if you don't have damp and have a cavity wall then avoid both. if yes to damp and you don't have a high humidity lifestyle then go for PVC. If not sure then follow the regs.
i do know the experts have conflicting thoughts on the worth of vapour barriers.
what i do know is about damp.
if for example a wall had penetrating damp ie water moving from outside to the inside of the house then a PVC sheet sealed with duct tape would be a way of stopping the damp getting into the house. a lot of houses these days suffer from condensation which escapes to an extent through the brickwork. the addition of the PVC would have the effect of making any condensation worse and potentially trapping moisture coming from outside. the question is whether in reality it's a problem.
the vapour barrier is supposed to sort this potential problem by allowing moisture to move outwards but not inwards from outside.
the verdict i believe is still out. the building regs say use the vapour barrier. if you tape a piece of plastic over a damp wall and leave it for 24hrs then you will definitely find water on the back of the pvc. given this i'm not sold on either. the question is where can this trapped moisture get to if the duct tape fails and what can it damage before natural ventilation can take hold and get rid of it.
in short if you don't have damp and have a cavity wall then avoid both. if yes to damp and you don't have a high humidity lifestyle then go for PVC. If not sure then follow the regs.
The idea of a vapour barrier is to stop moisture from the internal rooms from getting into the structure. Any latent moisture in the timber frame is allowed to escape via a permeable breather membrane on the outside of the timber frame, and then the timber frame settles down to an almost constant moisture content.
If moisture gets into the frame, then it could get trapped in voids or condense and allow mould to grow and rot to start
Also don't confuse the vapour barrier with proper breathable membrane. The membrane goes on the outside of the frame, and the vapour barrier goes on the inside. Vapour check plasterboard or taped foilback insulation can be used as the vapour barrier
If moisture gets into the frame, then it could get trapped in voids or condense and allow mould to grow and rot to start
Also don't confuse the vapour barrier with proper breathable membrane. The membrane goes on the outside of the frame, and the vapour barrier goes on the inside. Vapour check plasterboard or taped foilback insulation can be used as the vapour barrier
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