Timber kit vapour barrier...

[Carrerahill]

Hi guys, BC plans show foil faced PB to form the vapour control but I am thinking of going for a full vapour barrier internally as I feel I can get a better seal and tape all the laps with foil tape and around penetrations whereas once you cut the PB that's it gone. I know the area for sockets etc. equates to very little but I just see a full taped membrane being far better.

 

However, the Quinnthem foil faced PIR going between the studs is already a vapour barrier, so another option is 100mm foil tape and tape the insulation into the studs, so 25mm lap of tape onto the insulation, 25mm out on the stud side that forms the service void,  then 50mm over the face of the stud, then use another piece of 100mm tape to seal the other side, result is fully sealed in PIR - I could then use foil faced PB too.

 

So can those of you who have done this give me their thoughts and experiences please. Will I just get a roll of Protect VC foil and be done with it, or do I go down the taped PIR route? 

 

 

 

 

[ProDave]

What are you doing for air tightness?

 

One layer of Protect Bariair or similar over the frame (and insulation) will do both.

[Simplysimon]

6 hours ago, Carrerahill said:

Hi guys, BC plans show foil faced PB to form the vapour control but I am thinking of going for a full vapour barrier internally as I feel I can get a better seal and tape all the laps with foil tape and around penetrations whereas once you cut the PB that's it gone. I know the area for sockets etc. equates to very little but I just see a full taped membrane being far better.

 

However, the Quinnthem foil faced PIR going between the studs is already a vapour barrier, so another option is 100mm foil tape and tape the insulation into the studs, so 25mm lap of tape onto the insulation, 25mm out on the stud side that forms the service void,  then 50mm over the face of the stud, then use another piece of 100mm tape to seal the other side, result is fully sealed in PIR - I could then use foil faced PB too.

 

So can those of you who have done this give me their thoughts and experiences please. Will I just get a roll of Protect VC foil and be done with it, or do I go down the taped PIR route? 

 

 

 

 

if you've got a service void, then depending whethe you have osb internally, vcl over the osb. service void then pb. if no osb, then vcl over studs, service void and pb finish. a lot faster than trying to seal every sheet of ins to stud.

[Carrerahill]

21 hours ago, ProDave said:

What are you doing for air tightness?

 

One layer of Protect Bariair or similar over the frame (and insulation) will do both.

Approved (Council stamped) BC drawing simply says:

 

Limit of Infiltration:

To satisfy Section 6 of the Scottish building regulations 2014 edition the building to be constructed in accordance with the provisions of BRE Report 265:1994. Infiltration of air into the building must be limited as far as reasonably practicable by:

Sealing dry lining junctions between walls, ceilings and floors and at window, door and roof access hatches.

 

So essentially there is nothing I need to adhere to that standard room finishing won't seal - i.e. plaster skim etc. However, I do intend on trying to improve on this somewhat.

 

 

 

 

[scottishjohn]

If you are serious about sealing it and not just doing what the "persimmons" of this world do then the air tightness barrier should be on before any plasterboard  and house should be airtight without any plasterboard finish in place.

VCL over all stud work and taped around all  edges ,joints  AND all  penetrations of this "plastic bag!" .that should include where wiring and plumbing  are penetrating this barrier you are fitting to inside of your house.

then plasterboard it  and skim 

get air test before plasterboard ,then its easy to fix any leaks .

 

 

Edited May 8, 2019 by scottishjohn