Click here for more general advice on internal insulation.
Here are a few examples from the displays in CAT's visitor centre:
Internal insulation with cork & wood-fibre batts
The Cork acts as a secondary vapour check, inhibiting the passage of water vapour from the room into the wall; it also helps avoid cold spots where battens are fixed against the wall between the insulation batts. The 50x50mm timber battens are fixed to the brickwork through the Cork, holding both in place, using plugs & screws. The wood-fibre batts used here are relatively soft so need timber battens to support them and prevent them being compressed. The battens also support the OSB lining, which is screwed or nailed to the battens & acts as the primary vapour check, inhibiting the passage of water vapour from the room into the wall. It also allows pictures, shelves & cupboards to be fixed anywhere on the walls. Final decorative layer of painted plasterboard.
Typical U-value for the improved wall with the thicknesses of insulation shown: 0.44 W/m2K
Internal insulation with rigid wood fibre panels
The rigid woodfibre panels used here are designed to be fixed directly to the inner face of the wall using special screws supplied by the panel manufacturer. The surface is then finished with a foil-backed plasterboard. This acts as a vapour-check layer to prevent moisture from penetrating the wall & provides a decorative finish for final painting or plastering.
Internal insulation using hemp-lime with a lime or earth plaster.
This could be particularly good for building with solid slate walls (widely found in Wales) or similar. Natural, breathable insulation layers like hemp-lime and cellulose fibre will prevent moisture getting trapped within the layers and causing damp problems.
Hemp-lime is a mix of the chopped up pith of the stalk of the hemp plant & lime. It can be daubed on to the wall or, as here, lightly tamped into temporary shuttering. The hemp-lime is suitable for dealing with uneven surfaces. The final finish of plaster should provide a surface suitable for decoration. Hemp-lime & earth plasters have very good hygroscopic properties, meaning they can take in & give out moisture. This helps to regulate internal humidity levels.
Please contact us if you need to find suppliers of some of these materials.