Pic of driveway and garage. The single side will be enclosed.

It needs to match the style of the rest of the house, so can we see it? Will it need a door? Is there a window on the side already?

Yes it will need a door and there’s no window on the back side - brick - and we don’t plan to tear out brick to add a window

Here's some ideas....

You could also do a trellis on the over the 2-car doors and then some type of roof covering the single converted door. This is kind of what I'm thinking but not the style necessarily for your home.....

The top pic looks like what I’m thinking! 👍
Your suggestion about the roof coverings being different is a great idea!! Thanks so much!!

Unfortunately no matter what you do it will look like a converted garage, made all the more obvious by the fact that is it on the far side the garage as opposed to the house side. The drive only adds to the optics.

Hope the project goes well for you!

Your garage has good proportions and is quite attractive. I'd try to make a discrete pedestrian door within your garage door to maintain the current look of your attractive garage.

A quick google search comes up with the term walk-thru garage door or pedestrian door garage door. There are lots of pics of doors like this online. Seems they are used in exactly your situation when making a home offices out of .garage. The last shows the interior structure. I presume you could drywall over it for a cleaner look and more insulation.

I’ve never seen a pedestrian door like this! Thanks for sharing the idea! 🤔

I am a bit confused. Is this the far side of the garage away from the house? How will you provide access to it from the house? Must you go through the garage to get to this room? Do you even need an exterior door to the room from the driveway?

Here are pictures of the front and side of the house behind the garage.

Here is pa pic of the design I’m considering….

Your garage stall is probably around 9'ish x 22'ish. That is an odd proportion of Office space unless you have multiple users with cubicles. I would suggest, since there is no interior connection to the main house anyway, is to build the office towards the back of the stall. Leave the overhead garage door as is for a shallow 8'ish Storage Area, which still can be accessed from outside if one so chooses.

IMO the inspiration pics of a man door in a converted overhead garage door are hideous and ill functioned and ill conceived. You can still tell it is a jerry rigged converted garage and you will still have the same vehicular driveway right up to it and causing water infiltration issues.

I like the inspi pic. i think something like that could be incoraporated into something really nice for your new office space. draw to scale to make sure you like it on your home

3onthetree’s suggestion to keep the garage door portion of the garage while enclosing the back portion of the garage space is clever! You could store sporting goods, a riding mower, etc. items that might go into a yard shed there. Your idea of the double french doors with carriage lights might be appropriate for the wall facing your back yard. You could build a fence with gate signaling that as an entrance to your office if work requiring exterior access is necessary. Otherwise, just a window…assuming you can get into that part of the garage/den from your house.

Would suggest the wall where the garage door is be frame and finished to match the look of the larger garage door.

If I had an office I would want some natural light. I’d only use the back of the space for an office if I would be adding a window. But that is up to one’s own preference.