Building Construction Handbook, Eighth Edition

A standard block with mortar is 450¾225 mm = 101250 mm^2

A standard block format of 440¾215 mm =94600 mm^2

The area of mortar per block = 6650 mm^2

Proportional area of mortar = 1012506650 ¾^1001 = 6„57%(0:066)

Therefore the proportional area of blocks = 93„43%(0„934)

Thermal resistances (R):

Outer leaf+insulation (unbridged) Inner leaf (unbridged)

Rso = 0„055 blocks = 0„555

brickwork = 0„122 plaster = 0„081

insulation = 2. 631 Rsi = 0. 123

2„808 0„759

¾100% = 2„808 ¾93„43% = 0„709

Inner leaf (bridged)

mortar = 0„114

plaster = 0„081

Rsi = 0. 123

= 0„318

¾ 6„57% = 0„021

U=^1 R=2„808^1

+0„709+^0 :^021

= 0„283W=m^2 K

Thermal Insulation, Calculating U-Values---2