Insulating skeiling with kingspan

[JJH128]

Hi there,

I’m currently renting a mid-terrace house with some friends. The top floor consists of two attic rooms and a landing, which are all freezing. Both bedrooms have access to the eaves, and after crawling around inside, it turns out that most of it is uninsulated, apart from about 30mm of poorly installed fibreglass in some places.

I am considering buying some kingspan and getting a professional to do the entire sloped roof, from the bottom of the eaves, to the apex. The issue is, that there are two large sections of skeiling at the front and back of the room, about two metres from top to bottom. The rafters are about 75mm deep, and sit directly on the plasterboard underneath, so after leaving a 50mm air gap for ventilation, there will only be space for about 20-30mm of kingspan, which will be difficult to install given the size of the section.

I’m wondering if 30mm of kingspan will make any discernible difference to the temperature of the room. There is more space to work with in the eaves and space above the rooms. Would it be worth putting 30mm of insulation in the skeilings, and adding another layer of kingspan in the eaves and top space, or is insulation only as effective as its weakest point?

My other consideration, is installing kingspan inside the room and painting over it, but given that my housemate on the top floor isn’t as bothered about the cold as I am, I doubt he would want to lose the headspace, and doing this to one room would be pointless.

I would very much appreciate some guidance with this, as I am completely amateur in this area. Is there another solution that I’m missing?

Many thanks is advance,

Josh

 

[noseall]

I’m wondering if 30mm of kingspan will make any discernible difference to the temperature of the room.

If you are going to take the plunge and endure the disruption, you may as well do it right.

A typical raked ceiling would have 100mm of Celotex between and another 50mm of Celotex across the rafters. Both layers foil taped and 12.5mm foil back plasterboard to finish. Put 300mm of fibreglass loft roll up there (100mm between rafter and 200mm across in opposite direction), on the flat bit and you'll be toasty.

If you haven't the tolerance for 100mm of Celotex plus a small gap on the cold side, then add a thickening batten the rafters till you have the depth.

EDIT: All depends if you simply want to marginally improve or actually feel some tangible benefit.

 

[noseall]

given that my housemate on the top floor isn’t as bothered about the cold as I am,

Poorly insulated top floor raked ceilings are unbearably hot in the summer.

 

[^woody^]

The bigger issue is getting the landlord's permission and building regulation approval.

Do it wrong and there are rot and fire implications.

If you are going to do it, install as thick a layer of insulation as possible, and be careful of draughts within the void that could defeat the insulation. These draughts would be different to any ventilation gap that may be required.

 

[cdbe]

I this situation (rented property) I think realistically and practically you'd be better increasing the level of heating in the areas in question - larger/more efficient radiators (but the same "rented" issues) or just a few plug-in electric radiators.

 

[Diver Fred]

Ask the landlord. Did you get a copy of the Energy Performance certificate from the landlord when you signed the AST? (certainly sounds like the house doesn't meet the standard.)
The house has to a minimum of 'E".

You shouldn't be doing any work of this type yourself without written permission from the Landlord.

 

[John D v2.0]

30mm of Kingspan would make the world of difference if installed properly, compared with nothing at all. But it wouldn't be close to current regs.
Your problem apart from the ones with permissions, would be installing it without draughts making it useless

 

[endecotp]

My other consideration, is installing kingspan inside the room and painting over it

You need a layer of plasterboard below the insulation for fire safety reasons.

 

[JJH128]

Thanks for all your replies.

All depends if you simply want to marginally improve or actually feel some tangible benefit.

That's my biggest worry, especially if there are gaps due to the awkward installation. I think ultimately I will have to rally my landlord to do the job. He's been reluctant even though we offered to pay for the full sum, but it seems like the best way forward.

Ask the landlord. Did you get a copy of the Energy Performance certificate from the landlord when you signed the AST? (certainly sounds like the house doesn't meet the standard.)
The house has to a minimum of 'E".

The certificate gives it a 41, but does mention that the top floor rooms and roof are uninsulated. Really serves me right for not checking it before moving.

If he says no then my last solution may be Wallrock KV600 Thermal Liner, because I can put it on the walls and take it with me when I leave. Does anyone have experience with this product?

 

[endecotp]

Wallrock KV600 Thermal Liner :

thermal wallpaper; don’t bother.

 

[Diver Fred]

That's my biggest worry, especially if there are gaps due to the awkward installation. I think ultimately I will have to rally my landlord to do the job. He's been reluctant even though we offered to pay for the full sum, but it seems like the best way forward.

Think he is concerned about the cost and with you doing the work puts him in a difficult position with Section21 (notice to go) and even more so with Section8 notice.

The certificate gives it a 41, but does mention that the top floor rooms and roof are uninsulated.

Something doesn't sound right - maybe the assessor thought that only the lower floors where to be lived in.

If he says no then my last solution may be Wallrock KV600 Thermal Liner, because I can put it on the walls and take it with me when I leave. Does anyone have experience with this product?

Don't bother.

To be quite honest your best solution is to move once you can (before next winter). With an AST what you are talking about doing is the landlords responsibility (cause I don't think your tenancy is a 'registered' one). I think you have one of those landlords that gives the trade a bad reputation and makes it worse for the rest.

 

[HERTS P&D]

Your a tenant, put a jumper on or move.

Andy