Drylined Walls Insulation – Design Guidance
To minimise thermal bridging at window and door reveals insulation should be installed along the face of the reveal and butted to the window frame (figure 22). If space constraints preclude the use of battens, the plasterboard should be fixed to the wall through the Ballytherm insulation boards.
Thermal bridges can also occur where interior walls meet external walls; one solution is to extend the insulation for at least a metre along both faces of the internal wall, although to avoid projections in the wall it may be appropriate to continue the insulation to an internal corner (figure 23).
In intermediate floors, insulation should be placed between the inner surface of wall and the joist, which runs next to it (figure 24).
Walls must be prepared for installation: projections such as skirting boards, architraves and copings should be removed to give a smooth surface, uneven walls may need to be rendered; service fixtures such as sockets and switches should be removed to be re-fitted later.
Existing finishes with a high vapour resistance, such as vinyl wallpaper or gloss paint should be removed to avoid problems with condensation.
The cavities formed by the battens may be used for service runs to reduce penetrations through the insulation where existing services are taken through the insulation the penetrations should be sealed. Lightweight fittings may be fixed to the plasterboard, but fixings for heavier fittings should be taken back to the masonry.
Additional battens should be used to support heavy horizontal items.
a insulation fitted along face of reveal b insulation extended along face of internal wall c insulation between inner face of wall and joist
Further Advice & Information
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