Part L1B

[keen2learn]

I live in an 1895 stone built terrace with no cavity, this year I plan to internally insulate the bedroom wall it's the full width of the front of the house it was originally lime plasterered but it seems over the years it has been skimmed with gypsum plaster so no longer breathable and the plaster has blown in quite a significant area, I was thinking of removing all the plaster back to brick across the whole wall, and fitting 50mm foil backed rigid insulation with 12.5mm plasterboard on top of that and skimming what do I need to be aware of to be compliant with part l of the building regulations and is it notifiable many thanks and sorry for the essay

 

[cdbe]

The problem is that the regs insist on a minimum standard, which may involve a thickness greater than you consider acceptable in terms of loss of internal space. Probably best to adopt the "anything is better than nothing" approach. Realistically there will be no consequence of not notifying the work, other than you may not get any "credit" if you have an EPC.

Make sure you foil tape all the joints in the PIR to create a continuous vapour barrier.

 

[keen2learn]

Deleted

 

[keen2learn]

The problem is that the regs insist on a minimum standard, which may involve a thickness greater than you consider acceptable in terms of loss of internal space. Probably best to adopt the "anything is better than nothing" approach. Realistically there will be no consequence of not notifying the work, other than you may not get any "credit" if you have an EPC.

Make sure you foil tape all the joints in the PIR to create a continuous vapour barrier.

Thank you for your reply, is there a way to calculate the minimum thickness required to meet regulations, also just a thought with part L1B covering renovation, if the existing plaster was repaired and left in place so not materially changing the existing fabric of the building would this negate the need to adhere to the part l regulations at all.

 

[^woody^]

The requirement is that if you are renovating more than 25% of the total wall area (all external walls), you notify the council and work out how much insulation you should add to achieve a target u-value of 0.70 W/m² °K , and base the decision on practicality, feasibility and a payback of 15 years - ie you need to save more in the next 15 years than what it costs you to do.

Or you just do it. In your case one bedroom won't require and application.

 

[keen2learn]

The requirement is that if you are renovating more than 25% of the total wall area (all external walls), you notify the council and work out how much insulation you should add to achieve a target u-value of 0.70 W/m² °K , and base the decision on practicality, feasibility and a payback of 15 years - ie you need to save more in the next 15 years than what it costs you to do.

Or you just do it. In your case one bedroom won't require and application.

Thank you for your reply, what element is considered renovation, is it the removal of the existing plaster, therefore materially changing the fabric of the building, or is it the adding of insulation that falls under renovation.

Kind regards

Carl

 

[^woody^]

The wall is the thermal element. Renovation is work on the plaster, render, cladding or the wall itself