Gypsum Plaster

Plasterboard thermal linings will increase the thermal response in infrequently heated accommodation; the effect can be enhanced with metallised polyester-backed boards which reduce radiant as well as transmitted heat loss. The addition of such linings for either new or upgrading existing buildings reduces the risk of thermal bridging at lintels, etc. (The thermal conductivity of gypsum plaster is typically 0.16 W/m K.)

Table 13.2 Typical thermal conductivity values for various building materials

Material

Thermal conductivity (W/m K)

Aerogel

0.018

Phenolic foam

0.018-0.031

Polyurethane foam (rigid)

0.019-0.023

Foil-faced foam

0.020

Polyisocyanurate foam

0.023-0.025

Extruded polystyrene

0.025-0.027

Expanded PVC

0.030

Mineral wool

0.031-0.040

Glass wool

0.031-0.040

Expanded polystyrene

0.033-0.040

Cellulose (recycled paper)

0.035-0.040

Flax

0.037

Sheep's wool

0.037-0.039

Rigid foamed glass

0.037-0.048

Urea-formaldehyde foam

0.038

Hemp

0.040

Corkboard

0.042

Coconut fibre boards

0.045

Fibre insulation board

0.050

Perlite board

0.050

Straw bales

0.050

Exfoliated vermiculite

0.062

Thatch

0.072

Wood wool slabs

0.077

Medium density fibreboard (MDF)

0.10

Foamed concrete (low density)

0.10

Lightweight to dense concrete

0.10-1.7

Compressed straw slabs

0.10

Softwood

0.13

Oriented strand board (OSB)

0.13

Hardboard

0.13

Particleboard/plywood

0.14

Gypsum plasterboard

0.19

Bituminous roofing sheet

0.19

Cement bonded particleboard

0.23

Unfired clay blocks

0.24

Calcium silicate boards

0.29

GRC - lightweight

0.21-0.5

GRC - standard density

0.5-1.0

Mastic asphalt

0.5

Calcium silicate brickwork

0.67-1.24

Clay brickwork

0.65-1.95

Glass - sheet

Individual manufacturers' products may differ from these typical figures. Additional data is available in BS 5250: 2002 and BS EN 12624: 2000.

Notes:

Individual manufacturers' products may differ from these typical figures. Additional data is available in BS 5250: 2002 and BS EN 12624: 2000.

Sound transmission through lightweight walls can be reduced by the use of two layers of differing thicknesses of gypsum plasterboard (e.g. 12.5 and 19 mm) as these resonate at different frequencies. The addition of an extra layer of plasterboard attached to existing ceilings with resilient fixings can reduce sound transmission from upper floors particularly if an acoustic quilt can also be incorporated.

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