@MissConductUS It's because it's significantly cheaper to extend than move. To buy a house that would give us the space that we want would cost us around £200,000 more than our current house is worth. And that's just purchase price,that doesn't include all the fees associated with moving (solicitors, estate agents etc). To do the extension, it'll cost us about £60,000.
We've looked at other properties that are around £100,00 more than our house, that have kitchens the size we want but invariably DS2 would end up with a significantly smaller bedroom (the 3rd bedroom is traditionally a tiny box room in many properties), so we'd stll need to do work to give us upstairs space.
Our plan is:
Convert the loft, put up a wall in our current bedroom (which is enormous) to create a double bedroom identical to DS1s and a new hallway for the new stairs.
Move DS2 into our old room (we have the loft). Convert DS2s bedroom into a bathroom (we currently only have one bathroom and toilet, and it's next to the kitchen).
Then we can do downstairs. Rip out the existing bathroom and kitchen, build an extension in the side recess and out the back. Giving us a huge space.
This way, we get large rooms across the whole house at a fraction of the cost.