Another insulation question...

[Jim Gap]

Hello all.

After almost 18 months of moaning to my landlord about my place being cold (to the point where condensation was freezing on the bedroom walls) damp and generally unpleasant to live in she has finally decided to do something about it.

The place was built around the 1930's, is a end terrace and has solid walls. She's decided to go with internal lagging/insulation.. For whatever reason she's not lagging the loft space but rather insulate the ceiling?

The builder has been around today and from what I can make out he's going to screw some type of insulation boards to the walls, does this sound right? I'm no builder but from what I've been reading internal insulation is a little more involved than screwing boards to a wall..

If anyone here has experience with this type of insulation would you be kind enough to give me a basic breakdown of what's needed to do the job correctly.

Thanks...

 

[Doggit]

The normal method would be to put 2x1 battens on the wall at 600 centres, and then put 25mm cellotex insulation between them, then 25+12.5 of cellotex and plasterboard fixed to the battens, then skim the wall. The insulation across the battens stops cold bridging where you'd see lines down the wall where the battens are. If you can get into the loft, then you'd put 100mm of rockwool insulation between the joists, and then lay 170mm of rockwool across the joists, so I assume that they can't get into the loft, otherwise trying to put insulation boards and plasterboard on the ceiling is stupid.

But it is possible that they are going to screw the boards to the wall, and then screw the plasterboard through the insulation to the wall behind, and it can be done, but it's also riskier as you don't know where the screw are going to end up.

I think someone doesn't know what they are doing, but I could be wrong.

 

[Jim Gap]

Cheers Doggit. Had a chat with the builder today and apparently he's going to stick Kingspan to all the external facing walls/ceilings and plaster over it, does that sound right? One problem I see is the state of the plaster. For the last 6-7 years the plaster has been going through a cycle of wet in the winter and drying out in the summer, surely if he's gluing anything to dodgy plaster it's only a matter of time before the plaster pulls off and insulation goes with it, maybe?

As far as the loft goes, there's nothing stopping him getting up there, he just doesn't want to for whatever reason. A council worker doing work in the street suggested that all the plaster should come off, 3 coats of PVA to seal the brickwork, fix insulation boards then battens, then fill with loft insulation, plaster board and skim?

Rapidly looking like a bodge job on a budget!

 

[Doggit]

If he plasters onto the cellotex, it'll crack at some point, so he need plasterboard, and preferably battens to secure it to, and yes, unless he uses something like Safeguard damp proof to seal the walls, then the adhesive will very likely come loses at some point. And that's also why you can't apply 3 coats of PVA to the walls, as it will disilve again when it comes in contact with water; t's a glue, not a waterproofer.

If he's not prepared to get in the loft an do the job properly, then he can't be trusted to do any of the work, and I'd go back to the landlord and discuss you're concerns, and point out that the work will need redoing in a couple of years, and best to get it done now properly.

But are you on any benefits by any chance, that would allow you to get your local energy supplier to do the loft insulation.

 

[Ian H]

Can you dot and dab the celotex backed plasterboard? Could be that.

 

[Doggit]

You can do that with the non foil faced board, but if the wall ever gets wet, then it'll come away; best for internal walls. But it sounds like these guys wouldn't go to the expense of that stuff.

 

[Notch7]

The best way is cover whole wall with celotex. Then screw on 2 x 1 battens laid flat. Then plasterboard over.

There are no thermal bridges at the battens.

Ideally you should be doing 50mm celetex.

 

[Doggit]

On a cold day, you risk the battens showing through due to a temperature difference in the cellotex, and the wood, and the cold being transferred though from the outer wall.

 

[JenniferMichaels]

In that case the Celotex covering will help you.

 

[^woody^]

This will need a building regulation application

 

[John D v2.0]

The best way is cover whole wall with celotex. Then screw on 2 x 1 battens laid flat. Then plasterboard over.

There are no thermal bridges at the battens.

Ideally you should be doing 50mm celetex.

Excellent idea, what's more you get a services void for freeish.
You would get a thermal bridge where any internal walls or floor meet the external wall, but there's not a lot you can do except board the return a bit.

 

[Notch7]

This will need a building regulation application

Consequential improvement?

 

[^woody^]

Consequential improvement?

Renovation of a thermal element

 

[tomfe]

Your landlord will have to get it sorted anyway as there is new legislation coming into place to raise the energy efficiency of lets.
It's called MEES:
https://www.agentgreen.co.uk/blog/w...-the-new-minimum-energy-efficiency-standards/

 

[Doggit]

But that only applies to properties with an EPC rating of F or G, plus it only has to be done by 2020; so does the OP have the EPC for the flat. It should have been given when they moved in, and the landlord has committed an offence if she didn't.