Your job will cost what it will cost regardless of what Angie's List or local prevailing wages for plumbers might suggest.

Find a plumber whom you can trust, then pay him what he is worth.

How much of the wall to open and patch is another question. Only someone on site can tell for sure. A photo would help. Perhaps it will only be possible to replace the valves by cutting open the "drywall" or whatever your 1938 house has as wall surface.

It may be possible to have a set of dual shut off valves; there are ways, that experienced plumbers know. E.g. installing an "offset" or moving the pipe by an inch without stressing it. Besides, how much distance is deemed by you to be just slightly too far apart might not be too far apart.

Copper was the material for your pipes in 1938 but what material gets installed today is up to you or your plumber. Which fittings or adaptor to use is another question. If the new valves are to be soldered, this opens another batch of "things to know".

There are still many little things to know, katsmah, but if you read a lot you might be able to get a whole lot more comfortable with the work involved. A single device can be purchased that one can probably install all by oneself no matter how many left thumbs one has: a combination sharkbite / hammer arrestor / shutoff valve . After web searching, call the Sharkbite company for guidance to figure out what product.

A "master" plumber can work with pipes that still have water trickling down. The drier the better. The whole house water has to be turned off and the water in them has to be drained from all the pipes before cutting into them to replace a non-operating valve. It can happen that this takes a fair amount of time. If you and a handyman do this valve replacement, it will help your handyman helper if you drain the pipes before she or he arrives on the scene.

Nothing written in this post is intended to contradict manhattan42's statement. The job will cost what it will cost. To be more certain of success, hire a plumber who charges a high hourly wage. On average when you compare a low-price and a high price plumber, the latter will be faster, more efficient, making wiser choices, being smarter-for-you, installing everything in a better quality way with better workmanship.

Hth

FWIW....some years ago I, too, had a two-valve washer supply that was "slightly too far apart" for a single-valve control.

I was wrong about that. Plumbers see this all the time. Making such adjustments is part of their trade. In my case old-to-new transition took him about 1 1/2 hours. Of course I then had to repair/paint the wall. Materials and time charged for both.

How long it would take for your particular installation depends too many factors to predict. However, I reiterate, plumbers see this all the time. It's not that big a deal for them.

Thanks for the replies. The plumbing is easily accessible and I *think* should be an easy job for someone who has the right tools and knows what they are doing. I have a shutoff valve a little farther up the line, but it will also shutoff water to my kitchen sink.

The plumber offering this service has high marks on Angie's list and I've had good success using the list. Its a deal where their normal price is $120 per hour, but they are running a special for the first hour of work. I'm unemployed right now so I need to watch every dollar. I had some plumbing work done by another plumber a few months ago to repair a T connection and was shocked to get billed $170. I'm just hoping that this job wouldn't take more than 1 hour to do.

email the picture to a few plumbers. Not just one plumber who is listed on a list.

It would appear the pluming is not 1938 vintage.

That would be galvanized steel (or in a really upscale house threaded bras).

It is liable to the more than an hour since the water supply system will likely need to be drained, and that just takes time.

If there are shut offs above the laundry valves higher up it will go faster.

If you are going to hire the job out, i would have the saddle valve replaced while i was at it with a 1/4 turn valve. Those saddle valves, although still available for sale are just too risky. They usually fail when no one is at home. Ask me how i know. lol

I do have shutoffs - single lever ball valves - above the laundry valves that are good working condition, and a big concrete slop sink that is the low point on the line. Any time that I've had to have the water shutoff, it drained pretty quickly. I can definitely do that before the plumber comes.

nod702, thank you for pointing out the saddle valve. I assume it was for an ice maker the PO had many years ago. I've owned the house for almost 20 years and it's always been shut off. I realize that I should modify the scope of the work and have that valve removed.

That job is a simple DIY fix.....

You can clearly see a saddle valve on the cold water line and the elbows at the bottom of the risers where they meet the horizontal are 1/2" copper sweat 90's so that would indicate its copper pipe.

It is difficult to be certain from the photo but the Tee's at the faucets appear to be 1/2 sweat x 1/2 sweat x 1/2" FIP. If thats the case the faucets are then 1/2" boiler cocks, which are simply threaded into the 1/2" FIP Tee's.

Katsmah states that he has working zone valves on the line, so he should be able to get two new 1/2" MIP bolier cocks at any hardware for about $5 to $8 each.

To install he should begin by turning the water off at the zone valves then open the faucetts and allow all residual water in the line to drain out. Now hold the Tee with one wrench and unscrew the existing faucet with a second wrench, Apply some pipe dope on the treads of the new valves and screw them in,....problem solved.