Hi, I just come from a client place. She bought these teck timber. There is a company which import these timber boards from Indonesia. Terrible, thickness vary from 1 to 5 mm / width from 1 to 3 mm / no tongue and groove. costing 15 euro ft². What will be the best way to fix this, no sanding need. On concrete. I am planning to fixe a plywood of 18mm 3/4" / glue the teck timber with a polyurethan glue and nail it on top. What do you guys think.
How do I put a picture here?

If you are not comfortable with the quality of the material, don't install it, walk away and find a better job.

Yes, you are right, I will not be doing this job.

You could run it through a planer and then install and finish it. Sounds like they bought exterior grade lumber for decks. I have seen some rough 12 x 2 inch lumber from barns installed like that in commercial applications and not even run through a planer. Hey, it is what it is and if thats what they want...a barn floor then give it to them. It's all about customer expectations