Can I say
“ How many meter timbers do you need to build a cabin ?”
“how tall should timbers you need to build a cabin be ? “
I don’t have any context for this but I wonder If “ how many meter timbers” is correct or not . Most of native speakers say it is wrong but I couldn’t understand why we can’t say “how many meter timbers “while we can say “five meter timbers”? Is it totally ungrammatical or grammatically correct even it is weird?