Garage conversion

Yes we did it at our previous house. It was originally an integral garage with a flat roof. We had a sloping roof with a velux window and a large window where the garage door had been. All the walls, floor and ceiling had to be insulated and the outer walls had to have a breeze block layer inside as it was only single skin brickwork.We had to have the electric and gas meters moved and a new sub-floor laid.

It was really lovely and we were very happy with the result. We had it as a dining room with the back part as a utility room off the kitchen. The idea was that if we needed a ground floor bedroom, we could use it as one.

We didn't need planning permission but it was subject to building regulations and was inspected at every stage of the work.

We got three estimates and they varied wildly. We went with a small local builder who had lots of good ideas which we incorporated and had no problems at all from start to finish. He was a super guy.

Good luck with it - it does make a big difference to have the extra space.

We havent but my ex Dil has done it to make a bed and ensuite for my GD . She is now 18 but it was done about 5 years ago. She can access it from the hall so is quite self contained. I think insulation was a bit tricky and it had to have a larger radiator. Also all the meters were in there so they had to be aesthetically boxed in.
The ensuite is just large enough for a shower, loo and small handbasin , it is compact but more than adequate.
I would call it a success and wouldn't hesitate to do it if we needed it.

We converted our garage into a salon for me when I sold my business. Works really well for that so I can't think it wouldn't work for you..
We did have to apply for building regulations but that wasn't too onerous.

My brother did it for his elderly in-laws. Now they have both died it makes excellent guest accommodation.

Yes we did very successfully. Much the same experience as gaga - needing extra insulation and so on. We had plans done, we also had wildly varying quotes, took the "middle one" but still ended up with extra costs. We're very happy with the end result though.

We actually had plans drawn up to do this in our last house, to give us an internal entrance hall and a downstairs cloakroom. We decided instead to move, for reasons not related to the property, but had we stayed we would definitely have gone ahead with it. The extra space would have been invaluable.

I forgot to add ours is an en-suite (with loo and shower) without that, I don't know how worthwhile it would have been.

Thank you all so much! I want to go ahead now but DH wants more time to think! Think about what!!!

glenfinnan I've just re-read your OP and you have hit the nail on the head: our house now feels like two flatlets with a shared kitchen. Someone could easily live in the downstairs guest bedroom and the only room in the house we would meet up would be the kitchen.

I don't include the lounge because (a) many people nowadays (I might even say most) will watch or read stuff on their laptops or tablets so don't need a big telly, and (b) our converted room has a door that opens on to a patio so if they want more leisure space, that would be it (weather permitting).

I have never regretted doing it. When my son and DIL and the little one come to visit now, they are almost independent, and we do not have a big house. The new room has made all the difference.

I'm almost ready to retire now and my mother is thinking about moving in to our 'annex'. Ours was a double garage so she would have 3 rooms and a shower room. If I'm prepared to give up my utility room she would also get a small kitchen.
My husband did all the insulation and partitioning, the two double sliding outside doors were the most expensive items.
Altogether it must have cost about £15,000. Well worth it
as long as you have enough parking IMO.