Rear extension close to detached garage

[SwedeInLeeds]

We've finally got a viewing for a fairly large, reasonably priced house that we're seriously considering.
There's just one nagging problem, we'd like to extend in the future to create an open plan kitchen.
I just realised that the detached garage can cause some problems with this.
I have overlaid what I was thinking to do in the attached image.

The red outline shows the dream, but I assume we would not be allowed to join the detached garage up to the main building?
Would it even be possible to do just a rear extension that would touch one of the walls of the garage?
Otherwise we could potentially do the blue outline which should be big enough, but I am worried about the resulting oddly shaped corner.
Any thoughts/suggestions?

Bump as I am thinking similar on the house we are buying

Totally depends on your local council's planning department. A rear and a side extension could be permitted development (but not the extra corner between rear and side extensions) so that could be your worst case scenario.

Has anyone else in the road done this? You could ask an architect with local knowledge to take a look for you. Bonus if they have good relations with the council planning Dept.

We just extended, took down the detached garage and moved it down the side of the house. Built the 1st floor extension on top of it. We could then extend as we wanted out the back and to the side.

Slightlydustcovered, was that permitted development? Would you mind sharing approximate costs for moving the garage?

I would have a good think whether you (and future residents of your house) can live without access through to your rear garden. My in laws have no access and it’s a bit of a pain bringing bins through and any garden stuff.

Then just talk to your council planners

Depending where you are, and whether you're talking about a double or single side extension, you won't get planning permission to go all the way to the boundary. Here (and I think lots of councils are the same - have a good read through the planning documents - its often in something called SPD or supplementary planning document), you need to leave 1m between the boundary and a double storey extension, and 75cm between the boundary and a single storey extension. You used to be able to extend all the way to the boundary with single storey extensions - we're on a street of 40 houses and I would say 10 or more have all done this - but not in the last 10 or so years. Councils want to avoid the street looking like terraced housing (referred to as maintaining the street scene etc) and maintaining access to the back of houses from the street.

It looks very much like the footprint of a 1930s / pre-war semi - as a pp says, most people knock down the garage & move it to the front of the side extension and build above it.

It's depends on whether blocking the garage in completely is allowed and how many bedrooms to parking spaces it leaves you. Many councils insist you still have sufficient off road parking. Personally it would make the house unsuitable if the garage wasn't accessible because we use it.

After reading a lot more, the current plan would be to just do the rear 3m extension (75cm away from fence) going up to and attaching to the garage. Access to garden could be provided through garage. That would leave the driveway intact, wouldn't need demolishing moving and would leave us with an approximately 45m2 kitchen/diner, which I think is enough to make a nice open plan space.

Would this fall under permitted development? Any problems you could think of with this?

Isn't there a possibility that if the extension attaches to the garage, the whole thing is classed as the extension (i.e. the extension and the garage)? I don't think it would be classed a permitted development and you'll have to make an application for planning permission - maybe see if your council has a pre-application advisory service and give them a ring. I'm not sure you're going to get a definitive answer from MN.