Insulating the internal walls of a loft conversion

[BobbyBobby]

Hi,

I'm thinking of insulating the internal walls of a loft conversion (the wall between the main room and the storage area).
The storage area is insulated but still a little drafty The walls are made of a layer of ply wood and a layer of plasterboard.

What would be the best way of insulating the walls to the room area?

Thanks,

BB

 

[mointainwalker]

What's the make-up of the wall on the other side ? How much insulation do you have in the walls/roof of the storage area ?

 

[BobbyBobby]

The wall that is on the right of the second picture is the room wall. It is plasterboard on top of ply wood.

The silver foil insulation stuff (I don't know what it is called) is fastened to the roof all the way to where the roof meets the wall - but there there is a gap - for ventilation?

The chipboard on the left of the first picture is just to give a back to the storage area. So behind that is a void.

The storage areas are a bit drafty and cold - so I'd like to insulate the wall to the room. Should I also insulate the steelwork? Drafts might get under the floor?

Thanks,

BB

 

[BobbyBobby]

Does anyone have any advice? The Mrs is giving me grief

 

[AdrianMealing]

Celotex/Kingspan, that's what i have in mine, as for the flooring area, mine was filled with Rockwool before the floor went done, and then boarded over the top

 

[DevilDamo]

Shouldn't you have insulation on the block wall (assuming it's an existing wall), which is photographed in the distance?

 

[BobbyBobby]

I'm happy to insulate anything that needs insulating, I just need to know what does.

That is the wall to next door. The house is middle of three.

Is the storage area suppose to be an insulated warm area? It's still drafty when it's windy, so therefore I thought would be cold, hence wanting to insulate the room wall.

Thanks,

BB

 

[DevilDamo]

When insulating a loft for habitable purposes, you can choose to insulate over and beyond the stud/dwarf walls down to the eaves, like you have done or turn the insulation down at the stud/dwarf wall location. There's no harm in insulating both, but under Building Regulations, it's not essential.

If you have an existing block wall, that may need to be upgraded (i.e. by drylining) in order to achieve the min. u-value for either... a party wall or an external wall. As I don't know the build, it may or may not be required.

 

[BobbyBobby]

Hi,

Thanks for your reply.
What would you recommend I insulate the dwarf wall with? I've read about vapour barriers and all sorts of things, but am confused.

I'm also not sure what you mean on the block wall, what do I need to do there? I'm new to all this sorry and am unsure of the lingo!

Thanks again,

BB

 

[freddiemercurystwin]

Here you go, something like this will be Ok, a picture speaks a thousand words so they say,

Untitled

• freddiemercurystwin
• 25 Apr 2010
• 24

 

[DevilDamo]

Yeh, basically as FMT's detail

 

[BobbyBobby]

That makes sense, thanks. The storage floor is just on top of the ceiling battens though, so has less insulation. Is that ok?

What would be the best insulation to cover the steel work and dwarf walls with?

And what do I need to do with the wall to the neighbours?

Sorry for all the questions, thanks for the help so far.

BB

 

[freddiemercurystwin]

The dwarf walls can be insulated as per the drawing with 100mm Celotex/Kingspan.

A few layers of Rockwool can be fixed to the back of the steels and between/over the joists to meet the external walls making sure any ventilation routes remain clear.

The party wall should be insulated within the room, the part in your photo does not need to be insulated if you intend on insulating the dwarf walls. We presume the party walls within the habitable part of the conversion are insulated?

Its all written on the drawing tbh although you may need a magnifying glass if you've not got a big screen, slightly better version here though:

Untitled

• freddiemercurystwin
• 8 Jun 2010
• 20

 

[BobbyBobby]

Hi,

Thanks, this is making more sense now. The Dwarf walls seem fairly easy, just fill the areas between the uprights? Do I not need a layer of insulation over the wooden uprights or is that overkill? Is wood a decent insulator?

I think the party wall within the habitable area are insulated. They are plaster boarded and skimmed.

OK, the storage area floor is directly on top of the ceiling battens, with 100mm of insulation below. Is that sufficient or do I really need 3 layers? I also need to bring that insulation area/void (not sure what to call it up to the Dwarf walls so there are no gaps? Is there any high tech insulation that is thin so we don't loose too much room?

Thanks again,

BB

 

[DevilDamo]

Current u-values dictate more insulation is required at ceiling level (i.e. your loft floor) than that following the pitch line of the roof hence why FMT's detail shows three layers at the lower level. If you decide to continue the insulation down the roof pitch (like it is in the main roof), then you don't need to increase the thickness... just carry on with what you already have.