Graph paper works when you assign a dimension value to a square. Like each square equals 6 inches or 1 foot., maybe 8i inches for this layout. Use a straightedge or ruler to draw all lines and walls. A finished wall is 4-1/2" wide with a 2x4 and two sheets of drywall. Draw the walls in using space. I think you need more drawing and planning or an architect before you can get a good price on construction. If I were a contractor I'd overbid this by a lot to support the time necessary to generate the framing, electrical and plumbing plans necessary for permitting. 36" entrance clearance with the door means a wider opening unless you take the door off the hinges. 38" would be better. I see too many doors and hallway space. Too much open in thebath area with too little for components. Pocket doors can work for some spaces.

- if it were me i would want to maximize natural light and sense of openness so it doesn’t seem like a dark warren of rooms when finished, I would want to avoid that dark narrow hall in the center for sure (remember you will have to get furniture, plumbing fixtures etc in place up there) - make sure to generous with insulation etc as it will help with sound

A good architect can bring a plan like this to life and help with bids

Do you have a large budget? Ten years ago we researched doing this with our unfinished attic space and to convert an attic to accomodate heavy bathroom fixtures plus furniture to code was twice as much per square foot as adding an addition.

Meet with an architect then bring the plans to GC’s for bids. We asked for two sets of plans, one for the attic conversion the other with a side addition. We saved over 100k by adding an addition instead of finishing our attic.

Your plan for a 26’ x 35’ space seems choppy and crowded. An architect can help plan a more functional space.

Exploring the pros and cons of an addition versus finishing the attic may be worthwhile for both cost reasons and if you plan to live in this house when much older when mobility may be an issue.

You're more likely to go down a rabbit hole by crowd-sourcing a project like this than taking a list of your wants and needs to a good architect.

From looking at your proposed plan, I see some things that are not good. One is putting a closet on a corner--you're wasting good light and air in a room that is only used for storage. Usually closets are on interior walls, between rooms as a sound buffer.

Another issue I see is with the toilet room. I also happen to like a separate room for the toilet, but yours is all the way at the other end of the house from the bedroom. Which is about 30 feet away. Do you really want to have to walk 30 feet to use the toilet in the middle of the night? or even during the day?

If you're adding windows you need to consider how they will look from both the inside and the outside of the house. An architect can show you both interior and exterior elevations.

As I stated previously this is a huge and expensive undertaking. You need professional design help with layouts and budget, which you will get more efficiently with architects and contractors on site, not with strangers on the internet.

There is a myriad of existing conditions in every remodeling that will influence/constrain the design. Without knowing all of them you are already going down a rabbit hole.

Will the existing house and foundation support a second floor addition? That is the place to start, that a rough budget of 1K per sq ft location dependent will tell you where you are at.

THIS IS THE RABBIT HOLE!

You just entered the big deep "hole"

We'd like.......

"and firm up some ideas before going too far down a rabbit hole with architects/designers/contractors/HVAC/plumbers/electricians and everyone"

You begin with an architect at your home. A wish list, must have, would be nice, can live without.

Then you LEAVE that person alone. all he/she needs is what you want.

Trying to do that here from your "drawing" ?

Not every question is a crowd source at Houzz, despite talent that may be here.

This is ONE one one...at the site.

Or the nightly climb??: )

Thank you to all of you for your thoughtful answers! Sorry I didn't include the information that yes, we have already paid for someone to inspect the house to make sure that an upstairs addition is possible given the current structure (apparently, our foundation is wider/thicker than most and there are steel beams in the basement - this house was built a long time ago and we are probably the 7th owners (guessing) so we don't know why any of those decisions were made.

We have already interviewed a few firms and one of the reasons I posted is because one of the finalists is coming to the house for a site visit this week, and we expect to probably move forward with them (hopefully very soon!) So we wanted to try to organize our thoughts about what we'd like in order to give the real live professionals the best information.

We worked with an architect about 10 years ago (in another state, before moving here) on a gut reno and while it was generally a good process, we found that although we were very direct with what we wanted and did not, he nonetheless presented "his" vision and billed us for the time!

For example, we said in our initial design meeting that we absolutely wanted two separate walk-in closets, but his first draft of the floor plan had us sharing a massive closet. We said we wanted overhead lighting in every room (which could be dimmed, of course) plus sconces on wall and table lamps and he only put sconces on wall because he personally doesn't like the harshness of overhead lights. Ok, fine, but he isn't the one living there and I want hospital-level operating room brightness once per week for cleaning. Plus, having poor vision generally, which I told him, I always find that the more evenly distributed light from overhead (even if dimmed) makes it easier for me to read, etc. than sconces and table lamps. He removed an existing closet that was on a wall between 2 bedrooms as it made the room proportions nicer. We agreed to this change as it did make the proportions nicer. However, what we didn't know (but he should have) is that after the reno was complete, the noise between those rooms was a constant annoyance.

It is pretty upsetting to be billed hundreds of dollars per hour for drawings of things one said one does not want, and to end up with noise as the end of the project. When finally moved in and asked about dampening the noise, we were told that the walls were insulated to the max... um, ok.

So that is why we wanted to at least sketch out our thoughts a bit and try to refine them before this upcoming site visit.

Roarah, what you are describing about cost to build upstairs being higher is something a few contractors have mentioned. Our lot is the limiting factor - the existing position of the house, driveway, existing pool, nice stone patio, detached garage (bigger than average as it includes a workshop and also has steel beams supporting a huge second floor with hay doors (!)) pretty much is driving the decision to add on upstairs.

This whole addition would be on the second floor, right next to our children's bedrooms so there is no extra climbing involved - sorry if that isn't clear - but the attic space we are hoping to use is right at the top of the stairs.

Currently, the house has a main floor bedroom facing west toward the street. In the year or so since we bought and moved in, we have just not slept well. The furnace turning on/other mechanical noises in basement wake us up during the night. We had those inspected and they are recent and working properly, and there is insulation between the floors. Perhaps both of us are more sensitive to noise or vibration, but that is the situation. The other noise is from the street - it isn't a super-busy road but it gets a lot of traffic at times as we live near a few schools and our street is a cut-through between 2 bigger local roads. And those two bigger roads are both feeders (maybe about a mile away) to major highways. So, while we don't hear highway noise in our yard, if there is an accident on one of them, Waze clearly reroutes highway traffic through our street (obviously, we didn't know this before buying, but it might not have mattered as there was almost no inventory to choose from.) So even sometimes when the street should be dead, late at night, there might be a burst of traffic. So we thought if we do add on, let's get the bedroom facing the back of the house for morning light and a quieter environment.

The other big dislike for our current bedroom is that way back when this house was built, it seems bathrooms and closets were just made smaller. So the bedroom has only small reach-in closets (about 4 feet long, but at least we each have our own) and the en suite bath has almost no bathroom storage and just a shower and no tub.

If we do the addition upstairs, that downstairs bedroom likely would become a home gym. And it could easily be a bedroom again to "age in place" in years to come, should we still be in this house and unable to climb stairs. My guess is that we will downsize before that, but life is unpredictable, so we appreciate the comment about mobility being an issue because anyone could twist and ankle or break a leg skiing or something, so we definitely would keep that bedroom/bath on main floor intact for the future.

The whole right side of that drawing is abutting the existing second floor which is why there are no windows there. We are fine with no window in the media room (that might even be a plus) and we were hoping light from the window in the powder room would spill into that interior hallway.

In the front of the house, the three windows are placed to align with the existing lower floor, so that from the street, the appearance is balanced and symmetrical. However, on the left sides and back of the house, we have a little more wiggle room. The two windows in the bathroom on the left side of drawing line up with windows below, but the ones further back in the bedroom area don't necessarily need to line up with anything.

I appreciate the comments about how far away the toilet would be from the bed (we don't get up often in the night to use it but for sure when one is ill, that can change - I'm remembering having stomach flu years ago and yes, this would be very far from the bed in that situation.) We will ask how hard it would be to move that around - the location it is in now puts it directly above a toilet downstairs.

Thank you all again for taking the time to reply! We will definitely be asking the pros how to maximize light and maybe some way to eliminate the hallway, move the powder room if possible, and reorganize bathroom....

I might start with HVAC. You might have to replace your current furnace and A/C for that much new living space.

FWIW I will say there are varying levels of skill for architects like any profession -we have worked with 3 in our life and 2 were excellent. The first time we worked with an architect he was not the right person for an extensive reno in a historic neighborhood (shame on us for not doing a better job vetting his previous work) but we learned a lot working with him and were better clients for our 2nd and 3rd architect.

When you say you require something in your first interview qualify it further. Tell the person you will not accept or pay for a plan that does not include these requirements.

"Tell the person you will not accept or pay for a plan that does not include these requirements."

UNLESS..........structurally impossible

Severely compromises other aspects of more importance.......

And the myriad of reasons, that could arise and might bear listening to.

I'm not saying an architect is infallible....but you aren't an architect, just as no client of mine is a designer. Sometimes, "no" can be the best word ever, as LONG as an explanation and alternate and better suggestion accompanies that "no" word.: )

Communication......repeat, repeat, revise. etc...

AnnKH, you are so right about HVAC! We asekd an HVAC company that was here to fix something unrelated to the addition about the project generally (this was a few months ago) and he said that we would have to add a heating/cooling unit for this addition, and suggested propane to run it. We are going to ask more about that. There is no natural gas piped to our area (too much ledge rock probably) and there are some rebates for electric heat pumps (not overly generous though) and when we have the 5 day long spells of 8-14 degrees, the heat pump apparently would not be sufficient.

Thank you Jan, lala girl and Dan - we try to be direct and forthright with everyone and we do recognize that we are not in the design/architecture/building world, so will be reasonable with our demands! :-)

It is going to cost a pretty penny and this will be where we plan to live for at least 20 years, so we want to get it right.

Your words .....

"Get it right for the next 20 years........

Which is exactly why the fees for the architect, re draws and all, a couple missteps and another revise etc. over 20 years, are far less in cost than a build which leaves you staring at and living with regrets for those 20 years. Architect, not draftsman : )