Improving the Durability of Thermally Insulated Historic Solid Masonry Walls

Providing means of drying from the inboard face of the masonry when walls are insulated on the interior assists the overall drying potential of the faรงade. Laboratory tests simulating inward vapour pressure drives induced by solar heating were carried out on Multiple samples of RSI3.9 (R22) and RSI4.2 (R24) mineral fibre. The testing revealed that the drying potential of mineral fibre insulation was roughly equivalent to a 3 mm (1/8 in.) vented clear airspace. Combining mineral fibre insulation with a 3 mm (1/8 in.) airspace was shown to be a very effective means of providing the ventilation necessary for drying solar heated walls. The laboratory test results were incorporated into a hygrothermal computer model to simulate the potential for drying walls exposed to moisture. The laboratory tests and computer modeling have revealed that using air permeable insulation can be an effective means of assisting the drying of internally insulated walls.M.A.S