garage conversion

[Katebromley]

I'm looking to convert an integral garage into a room. Simple box shape - door into hall already there; just need to replace the garage door with a wall and window, so don't need planning permission. The builders I have approached say I need an architects plans (mainly for building regulations), but the quotes I've had are all nearly £1000. Seems a lot as we had a complicated design for an extension on the house for the same amount. Anyone had a garage conversion done and can give me a rough idea of cost for the plans and for the job itself? I can't get builders to quote without plans and I want to know if it's worth paying for the plans!

I live in Bromley (Kent/London) by the way if you hadn't already guessed from my name.

I agree £1000.00 seems a lot for some plans, on what is not complicated and does not require planning.
I’m in the NW and have seen people charged between £300 - £700.00 for drawings. Then there will be the submission of the full plans building regulations application. If you look on your Councils website, you should be able to calculate the fee for this.
Have a look on the CIAT website, and see if their are any Architectural Technologists (MCIAT) in your area. These are chattered bodies who can submit plans, and generally may be cheaper.

Thank you for your suggestions. Will do

We did a garage conversion on our previous house, OH did the plans himself and has also done them for our last 2 extensions. They just have to be to scale.

Thanks bellsbuss, that seems sensible as it's just a rectangular box! But, we had another builder round this morning and he won't do a proper quote or consider the work without "detailed architect plans" (of course, he recommended a friend). He also said we'd need planning permission which is odd as our council website says that's rare for an integral garage unless you are extending the space. His rough estimate on price was £19-£20,000 (space is 6 x 3.2 metres). It seems a lot as the walls are insulated (was built 15 years ago) and the walls already have plaster board rather than bare brick. He also said the concrete floor would have to be dug up rather than just timber-frame covered, insulated and screeded (which the first builder we had round said would be fine). Not sure who to believe.

Hi,
No you don’t need planning permission, as you are not increasing the space. This can be done under permitted development rights, presuming the house isn’t listed and your not in a conservation area.

The work should include;
Partially blocking up the existing door, and installing a new window. You may be able to use the existing garage door lintel.
Damp proof membrane over the existing garage floor with timber joists, insulation between and chipboard deck. Or dpm, insulation and then a screed. No need to dig up the existing.
Any walls which are not insulated to the right standard. Will need to be. This can be done with insulated plasterboard.
New (if not existing) sound insulation in the existing ceiling joists, if this is two storey. Or insulation between the joists if to meet regulations if single storey.
Obviously this is just an example of the work needed.

The work is quite straightforward. As PP suggested see if you can find a Architectural Technologist in your area, they should be able to complete the building regulation drawings the builders are requesting.

The main thing I would suggest is to see if anyone else with the same style house as you has already submitted plans online to see what you need for the builders.

Also don't just fill the garage door gap with a half wall and a window, match the window size with your existing ones. Any decent builder can tooth in (remove half bricks and replace them with full sized ones to adjust the apeture.

Think about where you want sockets and the lighting.

My original floor is concrete, they timber framed it then put insulation between the joists then floored over that. I am not sure why you would need it digging up. How deep is the step down into the garage?

We did need planning because they had removed permitted development rights and it went down as a change of use I think.

Years ago we almost photocopied a building regs drawing that was with the council planning, I think the council wanted to charge £27 as it is a legal document but we didn't need that so just had them photocopy some other stuff for our house. But you can view them at the council offices if someone has done a like for like planning application.

If you want to install a bay window you may need planning permission as it’s classed as an extension.

We've recently had a garage conversion and if you're planning on changing your garage door into a window then you do need planning permission.

We have just completed our garage conversion.

We booked to see a planning adviser at the council who confirmed we needed a certificate of lawful development but not planning permission.

You will need building regs, but you really don't need detailed plans for building regs. We had none.
The local building control officer visited us at each stage and advised the best way to proceed and at which stage we needed to call him in.

We did need to get structural engineer out for calculations of the existing concrete slab. If this is too thin to meet current regulations the whole garage might have to have extra foundations. This was the first thing building control asked for.

It's not as simple as insulating and putting in a window though. To conform with the latest regulations and preserve head height, we had to put a warm roof on-top of our existing roof.
Our main fuse board was in the garage and had to be upgraded to current internal domestic spec as after the conversion its position would be inside domestic space.

All in all it was well worth doing. We have two large extra rooms with a fibreglass roof for under £13,000. We are 90 mins from London to give an idea of uk location.