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6.0 SOLID WALL INSULATION: WHEN, WHERE AND HOW > 6.3.2.1 EXAMPLE DETAILS FOR INTERNAL WALL INSULATION
Casement continued POOR PRACTICE
GOOD PRACTICE OUTSIDE
OUTSIDE
INSIDE
INSIDE
Insulated jambs reduce cold bridging and mould risk.
Gaps between insulation boards allowing warm moist air to pass through insulation to masonry creating risk of interstitial condensation. Existing cill likely to be heavily weathered, with poor insulation qualities and risk of water penetration.
Air tightness tape between frame and lime parging to wall.
Cold bridge along reveal and frame leading to condensation and mould risk.
New insulating glass or possible whole new window. External face of wall made good including pointing remediation and replacement of any fractured and spalling brickwork.
Masonry wall originally moisture open and likely to be so now on the whole.
Moisture closed insulation reduces drying capacity of wall to inside creating risk of moisture build up.
Ability of wall to dry out maintained with the use of vapour open internal wall insulation.
WATCH POINTS
WATCH POINTS
• Cold bridge leads to possible condensation and mould around reveal • Moisture closed insulation tends to trap moisture
• Ensure that no rain penetration is possible around the jambs or cill • Ensure condition of external wall is good and all pointing is good and moisture open • Ensure wall can dry out to both faces by using moisture open insulation
SME522_Bristol wall insulation_PRINT AW02.indd 65
60mm max moisture open insulation maximises drying potential to both sides, helping reduce risk of moisture build up.
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