Garage conversion advice please

Though peeps don't like paying vat, a builder who is vat registered is normally a better bet, due to them not being afraid of the taxman so in turn is more honourable, (in theory).
As for choosing a builder ask for refences and ask peeps they've worked for their opinions.

As for the floor, how much lower is the garage floor to house floor.??

 

1. You choose a builder you feel most comfortable with, NOT the cheapest (unless he inspires confidence.) The Federation of Master Builders in my opinion is a bit of a scam, it sounds impressive but anyone can join it after registering for a fee and providing some references that they check in theory. It is a business after all, and the goal of a business is to make a profit, so I personally don't hold them in high esteem. Ask around family and friends if they've used decent builders, personal recommendation ALWAYS best.

2. Having done a few garage conversions over the years it honestly depends on the level of finish you require, where in the country you are, if the builder you choose is VAT registered, and what building control will require. Bearing in mind I'm doing this blind, but I would think around £11-12000 here in south wales is ballpark.

3. Concrete screed over insulation for me, depends how lower your existing garage is though, may have to dig down, though I have in the past at the customers requirements installed joists on top of existing slab and membrane, insulated between and laid chipboard flooring.

4. Forget underfloor heating as a primary means of heating the room, it's a secondary heat source, radiator and new pipework would be the best option in my opinion.

 

Every experience I've ever had with it has been ok, but was never overly impressed, if you're happy with the rest of the house then carry on, personal preference. 4.5 inches not enough of a depth to insulate and screed, may have to dig down if building control specify, if you're not involving building control it's up to you how you choose to proceed.

 

You should, but it doesn't stop some people going ahead without them, makes it more difficult later on should they come to sell the house. Building officer will specify what you will need regarding insulation levels and other fire related requirements.

 

I concur with comments on FMB and the £10-11k.

You will probably not need too much in the way of heating as you will be insulating the new space.

The floor shouldn't be an issue: put in whatever insulation will fit: 4.5 inches is 112mm or so less 75 screed leaves you 37 for insulation which will make a huge difference though not enough for a straight compliance. However the ADs allow for not supplying the full thickness if it is not economically viable.I have never had an issue with this situation If needs be do a small heat loss calc. Your window is probably less than the max allowed for simple heat loss compliance

 

How to choose a builder? You (a) go with your gut, which one inspires confidence, and (b) you get local references!

How much height can you lose by adding to the floor depth? As said above, any insulation there will make a huge difference, and it ain't worth losing valuable headroom by putting current insulation standards (100mm?) down there - that's a waste.

I don't know the pros and cons of each flooring method - they'll all work. Screed and chipboard/ply will both provide a good base for your tiles. If space is limited, then I suspect that a layer of insulation (whatever you can get away with) followed by a floating ply floor would be best from an insulation point of view (screed has to be a certain depth (50mm+?) to be strong enough, and this is 'wasted' space as it has little insulation value as such. Ply or chipboard, on the other hand, is thinner but also has decent insulation value itself as a material, so all good.)

Heating. By 'gas radiator' do you mean a normal 'water' rad heated from a gas boiler? If so, I think I'd go for that rather than electric simply as it would be cheaper to run. (I agree, underfloor heating is awesome - simply the best. Not sure I'd fit it if it had to be leccy, tho'.)

As for your final flooring, please check out 'Allura' vinyl tiles - they are bludy awesome quality and finish. Here's where sis' got hers; https://www.remlandcarpets.co.uk/vinyl-floor-tiles/forbo-allura

 

Im half way through a part garage conversion 4m x 2.8m ....a large integrated garage in bungalow with concrete floor. BI said to use foil backed insulation and a DPM so i dont need any screed even though the whole bungalow is on concrete platform. Would have thought this would be OK for you too? Mine is 120mm insulation, T & G chipboard on top then 18mm wood floor going down. A lot easier than floating floor, and will take weight of furniture etc.

Have you looked up Council website for planning and regs for garage conversions? I had to do quite a bit of reading up about it all. Fortunately didnt need planning approval but full conversion will. Theres other advice available online. Make sure youre actually going ahead with it before paying council for BI as i had to pay £330 ! Theyll give you a check list of what they'll inspect. Ask their advice! Expect the unexpected... on first visit they told me at least two things i didnt realise i had to do.

You say a stud wall needs to be built to cover meters and pipework, but how will access be provided in a stud wall? If electric meters itll have to be fire rated stud wall and insulation. My inspector even queried the thickness of both on mine.

I have had a builder do the stud wall, then electrician (moving plugs and putting in downlights) 1 window installed and plasterer in to get relevant certificates. Laying the floor myself and done the decorating. My window quotes were £2,300 and £995. (1.8m x 1.2m) The latter is accredited with FENSA, So guess which i went with!

Cost so far is about 3k not incl wood flooring. so 16k seems excessive for a full garage conversion unless you intend on handing over full project management to the builder.
Definitely seek out personal recommendations or checkatrade (where i got my plasterer) - the better tradesmen will be booked up, so be patient...i had to wait weeks for the plasterer, but it was worth it, and of course the whole job has taken some careful project planning!!

 

Always difficult to gauge quotes when some builders are vat registered and some not. Its an ongoing frustration for some to able to compete on a small job such as a garage conversion. What's important, is that you go through the various quotes with a tooth comb and double check that they are thorough with what they've quoted for and are basically offering the same spec.