That wouldn't be great for resale as if you make the closet the size that a master needs, your bedroom is much too tiny. If yo'regonn plan 100K + remodel, you probably hold look at an addition off the master as Plan 1. It'll be cheaper than the massive configuration redo with day$ of a master plumber buried in doing pipe$.

Or are we better off just leaving our bathroom small? It doesn't "fit" with the big size of the bedroom itself. I'd like to join our two walk-in closets, but my husband likes them separated even though his is in the hallway.

The MBR is 3 stories up, and this house is already much larger than we need, so we won't be adding onto it.

My pipe dream is to have a separate tub and shower.

So what if you leave the bathroom alone, and turn Bedroom 5 into laundry/DH closet? Do the office as you proposed, and add the closet in the bedroom. You can do the bathroom reno later - but this would meet most of your needs, at a lower price.

You can always return the office to closet when it's time to sell. In fact, I'd leave the door to the bedroom (but treat it as a wall in the office), just in case.

I definitely don't want the laundry in our room/closet. I had that at our last house, and hated the lack of privacy when guests needed to do laundry.

My closet and my husband's closet are both large. We don't need more closet space. My only real objective is to enlarge our bathroom...

ETA: buuuut, maybe we expand the bathroom a little bit and then the closet is on the other side, without laundry. I'd want to put the toilet in a closet where it is right now if we were to do that. Though, we'd lose a ton of light in the long hallway if the two windows end up behind a wall...

I also wanted to add that we can DIY this, except for the parts where we're required to have a professional come in. And I'd have a pro do the shower.

I was thinking of a wall between laundry and closet - I didn't explain myself very well.

I think your plan has potential, depending on your priorities and the conventions in your neighbourhood (how quickly is resale an issue, what are the local expectations of a MBr, closet, MBa, etc).

It looks like it's time to do a little research/thinking. Your current 5th bedroom looks like it's 10 ft deep? Do you want a 10ft deep full laundry ROOM? Or would a closet with a stacking unit be enough?

Do you need a walk-in closet? If so, what kind of dimensions are you imagining?

In our current reno, we've decided to forgo a walk-in for a wall of deeper-than-standard closets. If you did a run of closets 3' deep by 14' along your back wall, you would still have a 14x20 bedroom, plus what would be more than enough closet space for us.

Alternatively, how big is your current bathroom, and how much bigger do you need it to be? If you're only trying to make space for a separate shower, taking over the closets that surround the back of your current bathroom might make enough room. You could then put the laundry in the 5th bedroom at the other end, backing onto the hall bathroom, and this might leave you enough room in the bedroom for your office, and let you keep the closets you have. Even a 9x10 room is likely big enough for your small office, leaving you 5 x10 for your laundry... (unless the closets are part of your 10x14 dimension?)

I hadn't thought of doing reach-ins, but we could do that. That's what we had at our last house, and it worked perfectly well. I like the idea of just blocking the door if we convert our current closets to a single room/office.

I'd like a real laundry room, because I hang a lot of stuff to dry and currently run a clothes line above the w/d (as I did in my last house, too). It would be great to spread out a little bit. Also, we always have 4+ full hampers and laundry baskets around.

Thanks for the suggestions!

This is a perfect puzzle for an architect here on houzz to work with your ideas remotely. I say that because ARG (or someone else) could have solutions for you that we just haven't thought about. Since your 5th bedroom isn't technically "legal" due to the septic tank size, taking care of this with a change that suits your needs and handles resale objections and potential pitfalls down the road is an excellent plan IMO. It is always best to handle these types of issues prior to considering a sale of your home - even if you think you will be there forever. The ideas that I think are worth pursuing are the long reach in closet so your current bedroom retains most of its current size; the separate laundry room in the bedroom area is stellar and the enlarged bath (but not necessarily the layout you originally provided).