Glulam beam help with classification

[mikke349]

Hi!
I thought I could read up on this, but I'm stuck! Hope to get some help.

What is the difference between glulam beam 56*225 GL24h and 56*225 GL28cs in practice.

 

[justusandersson]

28 stands for the bending strength in MPa. h means that all lamellas are of the same class (homogenous). c means that 66% of the lamellas (those in the middle) have a lower strength class (combined). s means that the beam has been made by splitting a thicker beam. Normally, 90 mm is the minimum manufacturing width. I don't believe 56x225 GL24h exists. It should be 90x225 GL28h. You can find the full description at the following link: https://www.svenskttra.se/siteassets/6-om-oss/publikationer/pdfer/hallfasthetsklasser-for_limtra.pdf

 

[mikke349]

Aha, thank you for the answer!
Hornbach sells one 24h and Beijer b sells the other 28cs, both as stock items according to the website.
But I still don't understand if one is, for example, stiffer or "better" than the other.

 

[justusandersson]

GL28cs is both stronger and stiffer even though the difference is not large. The strength can be determined from the bending strength, which in one case is 24 MPa and in the other 28 MPa. The difference in stiffness becomes evident when comparing the modulus of elasticity. For GL28cs it is 12500 MPa and for GL24h 11600 MPa.