Hi zack, I like your roof idea. (Vaulted and flat) best talk to a design person to see how achievable it is. We are having a roof lantern in the middle of the flat roof extension and went to see one with it. It looked amazing, making the ceiling look a lot higher. If your original house has high ceilings like ours, you might need to reduce it a bit in the extension as PD allows 3m for eaves. For a flat warm roof, you might need to go down in ceiling height. I found out that you would learn so much during planning! As for your utility, if you don’t mind the utility closet idea as opposed to a room, it is a lot easier to fit in without side extension. We toyed with side extension too for a utility but didn’t want to loose side access to the garden. So we are putting a utility cupboard in where your ‘dining room’ is. But it will also function like a hall way to the extension. I would go for an island to define zone too if there is room. Although in our case, it is more because I succumbed to island envy.

Hello looks good. Lots of space if you could also look into more open plan living. Where's the powder room on ground floor you are citing? is it under the staircase

Hi David, Jonathan has already given a great layout design. But here is a quick alternative design that I came up with. The idea would be to use up the whole garage as a new entrance and W/C with a utility at the back too. the existing hall and W/C could become a games room, playroom or storage to make up for loss of the garage. Then at the back you could have an L shape kitchen dining living room, with the stairs as a feature. Please let me know what you think? And I wish you all the best with your layout change project!! Phill @Jonathan - I get what you’re saying about utility rooms, but I think some people use them for much more than laundry rooms, such as a boot room, tool storage, garden equipment, cleaning etc. So it makes sense for some people to have it next to the kitchen with a back door too. In an ideal house I think it would be great to have a separate laundry space somewhere nearer the bedrooms as you suggest!

I think this might be the quickest/cheapest option. Assuming the space is big enough and is constructed in the same manner as the rest of the house (not single skin like a garage etc). Remove the door and replace with a window then build a wall to separate from the kitchen. Couple of days work plus decorating time.