lean to insulation

[mechanicalman]

Good Evening,

We have a single skin lean to that we have recently added a doorway to from the main house. We use it as a utility room, and are looking to "do it up" (at the moment it is just painted brick).

As part of the work we would like to insulate it. Now having looked at various threads it looks like you should batton it, and then use insulated plasterboard. The issue we have is that the room is already very small, and I would like to eat up as little room as possible (I am aware that this attitude will have an impact on the rooms insulation performance).

Has anybody got any suggestions as to what I should do?

In my head I am after a damp proof foil type insulation sheet, which I could then board over. But I know nothing!

Thanks in advance.

 

[tony1851]

Whichever way you insulate the walls, you would need to batten them out. The multi-foil sheeting will not save space as you need to have a gap on both sides of the quilt (ie 2 layers of battens , then plasterboard.
If the wall is reasonably dry, just fix 2x1 treated battens, with 1" kingspan between and foil-backed plasterboard. Won't be up to building regs standard but will improve matters.
You probably have scope for putting thicker insulation board in the roof.

 

[noseall]

As per Tony; the highest performing and thinnest products are the foam board insulators i.e. Kingspan, Celotex etc.

If you are going to the trouble of renovating and insulating, why not bite the bullet and do it to a decent spec. With the low winter temperatures we are experiencing in the uk at the mo', you may be disappointed with a mediocre effort, i.e. black mould appearing over the walls and ceiling.

 

[mechanicalman]

Thanks for the reply gents. You have both hit the nail on the head, I don't want to spend the time and money for it then to be sub-standard. I was just hoping there was a wafer thin product I have missed! It appear not, and I will do as you suggest.

Thanks

 

[EB1caneyeB]

What about the plasterboard with insulation attached to it (i think it was 60mm thick)? i think you just fix it like dry lining boards. This was done on a refurb i worked on where the walls were 9" solid walls.

Myself, i didn't think this was right as there wasn't a moisture barrier.

Just putting it out there

 

[tony1851]

What about the plasterboard with insulation attached to it )

That stuff is OK but very expensive. Also, it would still have to be fixed on battens as its a single wall. This would take up a lot of space.

 

[foxhole]

Unless the room has a heat source insulation is pretty pointless.The roof will be the main heat loss. Very little to gain if anything from wall insulation.

 

[EB1caneyeB]

Thanks Tony. I was just wondering.

My utility room is the same. People we bought off had put up battens with 25mm jabolite (polystyrene) in between 2"x1" battens then fixed plasterboard. The room is bloody freezing in winter though. Not too bad when heating comes on (double 800mm rad). Cos the cat likes to sleep in there i've put one of them low wattage greenhouse heaters in there. It helps keep it a little warmer through the night.

 

[tony1851]

Inch -for -inch, polystyrene is not as efficient as materials such as Kingspan or Xtratherm.
With this small thickness of any insulation material, its not exactly going to come up to Passivhaus standard anyway.
Even to meet the 0.28 now required by Building Regs would need a lot more insulation than 1" of anything, and the loss of space in a small lean-to would be considerable. As Foxhole said, it would be more cost-effective to put thicker insulation in the roof.
But if there's no heater to start with, it will of course be cold!

 

[noseall]

Unless the room has a heat source insulation is pretty pointless.The roof will be the main heat loss. Very little to gain if anything from wall insulation.

So very wrong.