Softwood grades

[ErrolFlynn]

I'm trying to gain an understanding of the various grades. There are H-grades (which relate to treatment - hazard levels). Then there are F-grades. Somewhat confusing.

Here's a snippet from our span tables. My interpretation, in the highlit example, is that if you use F5 then the largest span must not be more than 1100. With F7 and the same size timber, the largest span can be no more than 1200. And similarly, if you have MGP10 the largest span can be no more than 1400.

This implies F7 is stronger than F5, and MGP10 is stronger than both. To put it another way, if the span is identical for all three, the load-carrying capacity of F5 will be the least, with F7 being better, and MGP10 being able to carry the most load.

Tell me if I've missed something.

Here's a doc I found while searching the web - it says F5 and MGP10 are the same. Huh?

https://www.melbournetimber.com.au/p...-treated-pine/

Span.JPGSpan2.JPG

[droog]

In the basics yes you are correct.

Here is another resource worth having a read of.
https://barwontimber.com.au/pages/st...DR9eAczJgjeTz_

F rating originates from many years ago but is still in use.
MGP stands for Machine Graded Pine, it is a newer standard.
Both tell you the amount of force or load they can sustain for a given amount of deflection, the higher the number the higher the force or load they can with stand. As they are two different standards measuring similar properties of the timber beam you can interchange one for the other where the rating is equal or greater than the one it is replacing. A timber beam will only be measured and graded with one of the standards.

[mic-d]

Have a read of this https://timberlinkaustralia.com.au/n...-in-australia/

It will give you a bit more nuance.