Barn roof insulation - where to start?

[Socks4Watts]

Hi,

We are strongly considering (offer has been made) a grade 2 listed property with an attached former barn (has elec, central heating etc). This is the current state of the roof. With energy prices as they are, we will be looking to improve insulation wherever possible.

Taking an extremely simplistic approach, I would whack a load of insulation between the rafters and board it up, but realistically I imagine you need some sort of breathable insulation, and probably a lime render? What are your initial thoughts? I'm trying to get a feel for the workload and likely costs, and also whether it would need planning consent. Unfortunately I have tried to reach out to the conservation officer but just get routed to the listed building consent form on the planning portal. Thanks in advance.



Thanks

 

[Cubist]

Hello and Welcome,

Wow, what a wonderful building.

Hopefully you don't mean to render the walls, that would be a sin and a shame, and not applicable to a ceiling - and unlikely to be considered kindly by your local CO when you finally get in touch with him/her.

My guess is too that the walls are anything up to 2 feet thick and constructed of two skins infilled with rubble; a common technique. As such the heat loss through them will be relatively small compared to the roof which would, of course, be massive. Its hard to tell from the photo but I would guess that the rafters are probably 6 inches wide and therefore provide a good deep cavity to accommodate a good layer of insulation. There have been a number of recent discussions here concerning what material may be best for this and I'm sure that you will be hearing from other members who have a strong opinion on the matter; personally, I'm in the sheeps-wool camp. The big issue to my mind is how the insulation is covered; longitudinal boards that hide the rafters or panelled and plastered between leaving the rafters exposed. On this my view is that your CO will have something to say about that but would guess he/she would favour the latter.

Hopefully others may be able to offer more germane advice and recommendations but your COs input is vital before you make any decision.

Cheers,
Cubist

 

[Socks4Watts]

Thank you, indeed would not touch the walls. The aim is to leave everything as original where possible - however the ceiling is an obvious place to target both from an eco/energy standpoint and visually. I would want to leave all the main rafters exposed (and minimise potential C/O pain points!)

 

[malcolm]

I guess the CO is going to prefer internal insulation rather than raising the roof to add insulation.

For internal whatever anyone official says you would ideally have a well ventilated space between the insulation and the existing roof.

I'm going through a similar thought process for my barn. I'm thinking tiles, 2 inch air gap ventilated really well by something cunning that I haven't figured out yet. Maybe propping up the vapour barrier to make a gap above the walls.

Building regs will want at least 100mm Celotex-like insulation (roughly equivalent to 300mm loft insulation) and that's fairly sensible. But don't involve Building regs if you don't have to. There are some exemptions for listed buildings.

Thick insulation will hide most of the features you currently have visible from underneath. It's important to try to seal things to stop air getting from the room past the Celotex as it will result in condensation and drips.

I could never get in touch with my CO either even after a pre-application. I just decided what I wanted to do and put in a planning application.

 

[Black Timber]

Thread resurrection to see if you bought the place @Socks4Watts and if so whether you've got any further in deciding what to do with the ceiling? And likewise whether you've made any progress and if so what you have done @malcolm?

I too will be in a similar(ish) situation later this year and so am starting to read up on the subject now. Any thoughts from anyone else on the topic would also be much appreciated.

Cheers