I would want the traffic door no matter what, so 4-panel would be a must. If not Origin, move on.

Get a different supplier who can do what you want . I agree 4 doors and I do not like the look of the upper windows with the new ones on the lower extension.

Thnaks all!

@millworkman - agree the traffic door will useful but they seen to view as a negative as less ’clean’ I guess.

@Patricia Colwell Consulting - how about if we added bars on the windows like the first floor? would that blend better to existing house?

@petula67 - what an interesting idea. I would have never thought to do 5 windows! I can see what you mean on the proportions.

"agree the traffic door will useful but they seen to view as a negative as less ’clean’ I guess"

Because they do not offer one they will spin how they need to. No traffic door would be a non-starter for me. Think every time you want to go out the door you need to open the entire bifold. Not a smart idea, period. But just me opinion.

I prefer more glass and view from my windows. Especially if you have something to look at. I'd consider updating the upper windows to clear units without bars to modernize and blend with the new lower. The uppers have a lifespan and now could be a good time to replace them.

This book has some useful guidelines for window and door proportions. Fun to read, too: Get Your House Right: Architectural Elements to Use & Avoid, available as an e-book or used or new on Amazon.

Is this in the UK or maybe Canada? Looks like you are doing a contemporary addition to an older traditional house?

IMO the window matching the gable looks out of place & I question why the 2nd story windows don't match.

Exactly that @chispa - the UK planning rules are obscene and mean the side extension upper floor has to be smaller than the existing building and therefore the windows are smaller.

Some interesting ideas on how to blend the lower floor windows in. I do love that gable window though!

I think you have a bigger concern of where the rain water goes that enters the roof valley.

If you search with the term "contemporary house additions" in Houzz Photos, you will get several examples that might give you some ideas.

Most of the ones I saw seem to design the additon with straight lines and do all sliders in the back to avoid having to "match" older windows.

Contemporary Exterior · More Info

Large family home · More Info

The Ladder Kitchen · More Info

Wow, those modern windows on traditional old homes look very unattractive and weird.

Train wrecks

The first thing that caught my eye was the sills of the windows on the second floor banging into the roof on the first floor.

Even though those windows on 'historical' homes appear incongruous, they are locally acceptable because of the restrictions against change. I'd fight the battle over changing the uppers for an overall better architectural outcome.

If you have never lived in an older British home you won't understand why their owners are choosing large windows/sliders on the new additions! Things that you won't find in most older British homes ... main one is light and bright open living spaces!

@dan1888 - would you have one large casement window either side replacing each sash window or change the window positioning completely on the upper floor?

@HU-684871180, realistically who is ever going to see the whole rear of your house from the angle in the elevation? And do you care if a couple of your neighbors can? I'm assuming a typical British urban home and that you don't have a large property or garden. I would design it to maximize your enjoyment from inside, where you will be spending most of the time.

Those upper windows may have been the best option at the time the house was originally constructed. Small rectangles of glass assembled to give good interior light. Glass technology has progressed since then. But I still feel the 'best' available at the time is the correct choice. This time. Wider casements positioned more proportionally with consideration of the room use and view seems a better current choice. No bars. It's challenging because the lower structure widths are opposite of the uppers.