the topic lumber can not opened

Very interesting

木材是要看用在什么地方，然后再选择适当的木材

等级低的木材要用在什么方面合适？

It really is helpful. The course gave me practical insights. Thanks Alison

when lumber is well treated it life span prolong and is less expensive than metal

So, how then can we prevent lumber from defects?

Am really enjoying this course. Thanks to Alison.

So why are the places where they sale wood called lumber yard? mostly I don't see any lumber to speak of!