Insulating a single brick wall.

[Baileys bubble]

Hi all, 

I have an old lean-to I want to incorporate into my kitchen. 

My biggest problem is that although it has a damp course, the walls are only single brick. I want to attach insulated plasterboard to the interior and intended to use knauf boards and knauf plasterboard adhesive, dot and dab. 

However, I am concerned about moisture and damp crossing into the plasterboard through the adhesive.

Does the foam insulation (non foil backed) act as a DPM?

Will the adhesive hold to the brick wall? 

Do I need to fix another way? 

How...... 

Any help will be appreciated 

[Temp]

The best method is probably to build stud walls with an air gap. Make sure its air tight as any water vapour that gets through may condense on the cold brickwork.

 

Bricks aren't waterproof. If you want to fix direct I think the insulation manufacturers recommend fitting a membrane first or standing the insulation off the wall on battens...  

 

https://www.kingspan.com/gb/en-gb/products/insulation-boards/insulation-technical-hub/articles-and-advice/how-to-insulate-a-garage-conversion-wall-insulati

 

Internal wall insulation (IWI) on a garage conversion

The other, and probably more common, solution is to add the insulation to the inside of the garage. The simplest method of doing this is by using insulated plasterboard.

These plasterboards are mechanically fixed to timber battens, at 600 mm vertical centres, with either drywall screws at 300 mm centres or large headed galvanised clout nails at 150 mm centres. These fixings should allow for at least 22.5 mm penetration of the timber. The timber battens should be protected by a strip of damp proof course, placed between the batten and the wall. Timber noggins should be positioned horizontally at floor and ceiling level and at a maximum of 1200 mm vertical centres. This method provides insulation, plasterboard and a vapour control layer in one product.

If there is an impervious finish on the exterior of the wall, such as timber cladding or a waterproof render, which prevents moisture penetration then an insulated plasterboard could be fixed to the wall using dot and dab method. We would recommend that an exposure risk analysis is carried out by our technical services department before using this method as this does not apply in some areas of the country.

The other option is to build a timber frame system with a breathable membrane and insulation between the studs and plasterboard. This method of insulating the garage wall is probably unnecessary unless the walls are too uneven to fix the plasterboard and need straightening out, although plastic shims can be used behind timber battens if only minor adjustments are needed.

 

[Temp]

PS Building Control may have a view on how it must be done.

[Jason L]

You can fix timber battens on a DPC strip and then fix an insulated plaster board to the battens. 

[tonyshouse]

Much better without battens, they can rot, even treated ones, 

 

decide on a target U-value then insulation sheets and plasterboard or composites sheets stuck on and mechanically fixed 

[SimonD]

Why not use external wall insulation?