Any experience of exemption from Part L building regs for a historic building?

[Tigg]

Hi all - this is my first post here, so be kind

 

I have a very tiny barn in cornwall, where I'm from - it's over 150 years old, not listed, but it is in a conservation area, a traditional barn for these parts, made of granite, and in a mess - unused for probably 50 years or so, needs a change of use applied for, and in doing that we'll be asked how we're going to comply with insulation regs - sometimes it seems in these circumstances owners are expected to match new-build standards, but my argument would be that this has always been a breathable building, and to put 200mm of PIR everywhere will stop it breathing, leading to problems - it will also nab a large amount of the available space, as this barn is really tiny - so I'd be asking for the historic nature of this barn to be taken into account, including its breathability, and then asking that we use other insulation materials, probably aerogel in some form (I know, it's VERY expensive, but this is a tiny barn) - we can show calculations that would prove we were doing the best we could without damaging the fabric of the building, but has anyone out there actually DONE THIS????? in terms of speaking to building control, persuading them that you don't have to match new build regs, doing your best to get as close as possible to the regs etc - have you done this and how did you do it? I'd REALLY appreciate any experience anyone has of this tricky area - thanks very much - nick

[Mike]

Welcome!

 

There are some exceptions in Part L of the Building Regulations for 'listed buildings, buildings in conservation areas and scheduled monuments' and for 'historic and traditional dwellings'. However they only apply when the work would 'unacceptably alter the dwelling’s character or appearance' - in which case 'the work should comply with standards in this approved document to the extent that it is reasonably practicable'.

 

In theory you might qualify under the first of these, but in practice it's unlikely to help; it's more for when insulating internally and externally are both ruled out for heritage reasons, or double glazing can't be retrofitted to historic windows.

 

In theory the second case wouldn't apply as it's a barn, not an existing dwelling, but the Local Authority may be flexible on that if they want to see it put to use as a house.

 

22 minutes ago, Tigg said:

but my argument would be that this has always been a breathable building, and to put 200mm of PIR everywhere will stop it breathing

Don't use PIR. Vapour-permiable options are readily available and advisable - you'll find some topics on this forum.

 

In a renovation there are provisions for when the the full insulation standards can't be met but, from memory, they wouldn't normally apply in a conversion.

 

28 minutes ago, Tigg said:

aerogel

Is unlikely to be financially viable outside the World's major cities, where the property value /m² of floor area gained exceeds the cost of Aerogel.

 

25 minutes ago, Tigg said:

it will also nab a large amount of the available space, as this barn is really tiny

That's not an argument that will fly; you'll need to use clever design to maximise the space that is available.

 

Sounds like you need to find yourself a local architect experienced in restoring / converting old buildings.