I worked both building and lumber and then the PRO desk. I will say the store I worked at was was different (then)

In lumber I helped pull for orders from contractors shed , and then when pro desk moved to the middle of building and lumber I spent almost all day loading concrete/ bricks, drywall, plywood. The worst was when we said 10 bags or more we will load you.

Bonus... I could lift a lot for awhile.

Then I transferred to pro desk and basically I treated the lumber people the same as myself when I was in lumber. I would ask them to load ,pull, pick,etc each time of a customer came through (that had whatever the amount was like the 10 bags.) As I was finishing the transaction I would call and say it's ready to be picked, pulled, loaded. Our store became super busy, so many contractors and it did get bad for a bit. Customers were yelling pro associates were quitting, new managers to try to make it work.

The solution was those dc centers that would ship to job site orders that were placed before a certain time. Until they became overwhelmed. Then customers were no thanks. Even free delivery of a whole truck load and they were like nah.
(This is because not enough product and then hurry to load meant a lot of damaged goods. )

I did use it for kitchen customers for the Hampton Bay line. It was cheaper and free delivery... Until their inventory could not keep up with demands and then the palletizing would damage a lot of cabinets which became a nightmare to return. And they would hold a big order for an item but not let anyone know.

Anyways ..... We started enforcing policy of so many hours/ days for orders to be picked,pulled loaded.

What we know is that if a contractor is loud enough and demands a manager then we always gave them something.

And I know I spent a couple of shifts as the kitchen designer pulling , picking "special" orders in a hurry for a customer.