Did you ask the builder? Also, why are they using copper instead of poly tubing?

Your drywall will typically be installed to furring strips that run perpendicular to the joists. Using 1-1/2" furring will provide space for both piping and wiring on the bottom side of the joists. So you should only lose an inch and a half, not a foot. You will have to box the heat duct and beam. You need to watch the HVAC guys like crazy lest they drop their big piped into the living space rather than tucking them between the joists. They seem to regard a tall ceiling in a basement as an invitation to fill it. No choice for the runs that are perpendicular to the joists.

They just screw 2x2's to the joist, then attach the sheetrock. I like the copper tubing.

This is 100% normal, you should tell the builder/plumber that you intent to finish the basement therefore pipes should be run close to the hvac trunc. When finishing entire area will be covered by the soffit.

Since the duct reduces in width as it crosses the room, the pipes appear to be in the perfect location to be included in the duct soffit as Casey points out. There is no reason to run them through the joists.

Nothing wrong with copper. I have some copper supply pipes in my house but most of them are brass.

but another 1 ft or so due to having to drywall around the copper.

More like 2 inches....

You don't want extra holes in your joists anyhow, and think of all the extra labor to drill the holes straight with each other and fish the copper through them. Also if you look you will see there is ductwork between the joists and the copper cannot touch the ductwork. So the whole idea is moot anyhow. What they did is perfectly acceptable and correct. Copper plumbing is good btw, its actually an upgrade to pex in multiple ways. Solder used in ye olde days had some lead in it which is what was toxic. Solder used these days is lead free.

Agree with VIth

In our new build, we have copper pipes, definitely a big upgrade in our area. And yes, the solder used now is lead free.

In our area pex doesn't meet code so it's not even an option.

Just curious what area doesn't allow pex?

Since I was the one that left original statement about copper plumbing, here is explanation:

1) It is true that solder used now is lead free. Flux is still toxic. It suppose to completely evaporate ... But not really and leaves some residue.

2) IF you are on the well and water acidic it will react with copper with, but will not react with PEX.

I am an engineer, soldering/welding is something I can do with my eyes closed. Ten years back we had other house re-plumbed [by pros - not by myself], and water reacted with copper creating odd taste. Sections that I replaced with PEX were not affected. Just my .02 cents.

Plumbing solder is tin and antimony or tin and silver and are non-toxic. Lead bearing solder (for plumbing) hasn't been used in at least 50 years.

Flux is used to clean the tubing and fitting. The 'old' flux used zinc chloride - the flux looks like Vaseline, apply a very thin film to the tubing and fitting, cleans when the joint is heated. Now understand this kind of flux was used for probably 100 years to solder copper water pipe.

Today, there are NSF approved fluxes that are zinc chloride free. No need to worry.

Further, once you run some water through the pipe, the residual flux is washed away.

I have always lived / worked where there is decent city water, no problems with copper. Could very well be that well water, improperly treated, would react with the copper pipes.

Also consider, that if you have to use PEX, cause the water reacts with copper - maybe the water should be treated - because (untreated) it may be less than healthy for you!