Building Construction Handbook, Eighth Edition

BS EN 338: Structural softwood classifications and typical strength properties ~BS EN^338 strengthclass

Bendingparallelto grain(N/mm

2 )

Tensionparallelto grain(N/mm

2 )

Compres-sionparallelto grain(N/mm

2 )

Compres-sion per-pendicularto grain(N/mm

2 )

Shearparallelto grain(N/mm

2 )

Modulusof Mean(N/mm

2 )

ElasticityMinimum(N/mm

2 )

Charac-teristicdensity(kg/m

3 )

Averagedensity(kg/m

3 )

C14

4.1

2.5

5.2

2.1

0.60

6800

4600

290

350

C16

5.3

3.2

6.8

2.2

0.67

8800

5800

310

370

C18

5.8

3.5

7.1

2.2

0.67

9100

6000

320

380

C22

6.8

4.1

7.5

2.3

0.71

9700

6500

340

410

C24

7.5

4.5

7.9

2.4

0.71

10800

7200

350

420

TR26

10.0

6.0

8.2

2.5

1.10

11000

7400

370

450

C27

10.0

6.0

8.2

2.5

1.10

12300

8200

370

450

C30

11.0

6.6

8.6

2.7

1.20

12300

8200

380

460

C35

12.0

7.2

8.7

2.9

1.30

13400

9000

400

480

C40

13.0

7.8

8.7

3.0

1.40

14500

10000

420

500

Notes: 1. Strength class TR26 is specifically for the manufacture of trussed rafters.

2. Characteristic density values are given specifically for the design of joints. Average density is appropria

te for

calculation of dead load.3. For a worked example of a softwood timber joist/beam design using data for strength classification C24 (e.g. SSgraded European redwood) see pages 664 and 665.

Materials Testing---Softwood Timber Classification