Extension/garage conversion- where to start?

[TeaAndBiscuitsAndCake]

We are considering extending our house, but have no idea where to start.

We have a detached house with a double garage. We are variously considering converting (part of) the garage, or building on top of our part of the garage, or even potentially having a loft conversion. We don't think the house set-up is suitable for an extension (the narrow end of the house, off of the kitchen, would be the only part we could extend), but it may be possible.

As a minimum, we'd like another sitting room (which the children can use as they get older) and a shower-room/wet-room. At the moment, we have a family bathroom and a separate cloakroom, no en-suite.

If we had a two-storey extension, we would be looking at another bedroom(s), maybe an en-suite (in which case, we wouldn't need a shower room downstairs).

The garage is attached to our house only by a porch roof, but the garage itself is semi-detached to our neighbour's garage - their garage is not attached to their house at all. We would presumably need a party-wall agreement.

We don't know the condition of the foundations (whether they would need replacing before a two-storey build over the garage), or even if a two-storey extension is possible or would look strange (if it was joined to the single-storey garage next-door).

If we moved house to get the space we want, we would be looking at at least 150k more than our current house to get slightly larger rooms and an ensuite. To get an extra room, at least 250-300k more. We don't want to move, but we would like more space. Budget is not too much of a concern (within the parameters of staying put) but we would not want to spend our entire budget on a single garage conversion, so our budget kind of depends on what is possible. We had heard that a two-storey extension is not twice the price of a single-storey, so may be worth considering.

We just really don't know where to start. Do we need an architect first to design things, then a builder? What if the architect's design turns out to be way over budget when trying to find a builder? If we get builders first, how can we get quotes if we don't know what is possible? Do we need a surveyor first for the foundations?

Where do we begin?

Start by finding a designer, I wouldn't go for an architect, an architectural technician will be all you need. If you have a local fb group join that and ask for recommendations. Tell them your budget and what you want, they should take account of your budget in what you design. They can also advise if you need planning. Once you have their design you can apply for planning. While you are waiting the 8 weeks for planning you can get quotes from 2-3 builders. You'll also need a structural engineer for foundations etc, your architectural technician will probably be able to recommend someone they use, and will be able to work alongside. You'll need building regs approval which can be done at same time as planning.,

That's really helpful, thank you Sanch1.

You may find your garage is single-skin bricks and so may have to be demolished in order to build above it.

I would probably speak with a chartered surveyor (go via the RICS website) to understand your options.

Also look to see if there are any similar conversations in your road/area.

We did a garage conversion and utility room extension with an architect who also was the project manager. He came out and talked about what we wanted, measured up, did a draft of the plans and was able to give us a rough idea of cost there and then. And then we got the full drawings done and he provided us with a full itemised quote. He was brilliant - we didn't have to arrange a thing, he arranged everything with his trusted builders and materials, did site visits weekly to check things were on track, etc. And we just paid him and he sorted out everything else.

I'm sure we paid a bit more for the convenience, but his quote was way under the others we got from the big companies anyway, so I was happy to pay it.