DIY Basic Garage Conversion

[F54Mini]

Hi



We have an internal garage with bedroom above, whole thing was done as a two storey extension in the mid 80s



Bedroom above is fairly cold and we simply use the garage as dumping space.



To that end I want to convert the garage into usable space but with the ability to put it back later on if needed, so no building regs.



Garage door is being replaced in two weeks with an electric roller one so my plan after that is.

1. Build a stud wall behind the garage door, right up to the pillars. Insulate this with 75mm+ of PIR.
2. Install 75mm of floor PIR and 18mm tongue and groove boards to bring the floor up about level with the house, might be a few mm difference.
3. Ceiling is boarded already and has 100mm fibreglass 80s stuff above it so instead of ripping it down, I am going to add 52.5mm of insulated plasterboard and screw right through to the joists.
4. Add a radiator. Can either come off hallway one or get a plumber in to tap off Flow and return from boiler which is already in the garage.

Garage has a window already, it has cavity walls already and also a door from our hallway.



I’m thinking of just leaving the walls as they are, the rest of the house has cavity walls with no insulation in them so it should hold heat in the garage the same as the rest of the house.



It won’t be a permanent room, it’s going to be a playroom with sofa bed in case we have occasional guests.



Lighting and socket circuits are already in there so nothing much to do there either.



Anything I have missed?

 

[^woody^]

Anything I have missed

Invalid house insurance?

Means of escape?

Fire safety?

 

[F54Mini]

Invalid house insurance?

Means of escape?

Fire safety?

Has a door into the hallway right next to the front door. No different to a bedroom or many other rooms in the house.

Must be thousands of houses with garage conversions without building regs. It’s literally a stud wall and some flooring to be fair.

Let’s assume I’m going to use it as a workshop then.

 

[If in doubt...]

Sounds like you are literally doing almost exactly what I have recently done...... but I involved building regs and advised house insurance company I had an additional habitable room. It's worth doing, and will ensure you end up with a great job rather than just a reasonable job..... plus save a possible lot of hassle should you come to sell the place.

Looks like you are ok with fire escape angle.

Building regs might also want a bit more insulation in that wall, I went with 100mm between the wall studs and an extra 50mm across the lot. I put a door in the partition wall to get in to the workshop from the new habitable room and BC wanted a fire door (which was better thermally anyway), self closer and intumescent strips even though it became just a narrow workshop, subsequent owners might put petrol lawnmowers etc in there.

I sat my stud wall on 2 courses of conc blocks laid flat to give it all a better base - and my internal floor was quite a bit higher so I had to go with 220mm of floating floor insulation. DPM was put in on the garage floor before the insulation went down, then a slip layer on top, just under the floorboards. I know what you are saying that the walls match the rest of the house but BC do like efforts to bring any new rooms up to modern standards. I put 50mm insulated plasterboard on the external walls.

I replaced the existing window as it was old, and also shrank it a bit in length as it slightly bridged where the dividing stud wall needed to go. Used same electrics, just tidied them up a bit.

 

[^woody^]

Let’s assume I’m going to use it as a workshop then

You can call it what you like, but the fact remains that it will be unauthorised and uninsured.

And you say you say you will have guests stay in that room where the fire risk has not been addressed and with a gas boiler in their too. I'd not want that on my head trying to skimp on others or even my own family's safety. But, hey-oh I'm sure there's thousands of others who have done it.

 

[CharlesBR]

If and when you come to selling your house as well your house needs to be compliant if changes have been done. Trying to skimp on things and missing out doing building regs just because others do it is nonsensical. Building regs are there for a very good reason and you need to be compliant to save on any potential further problems down the road.

 

[Louis.]

Out of interest, at what point are building regs and planning permission required?

If you had a garage you want to insulate and fit a radiator in but one you'll never inhabit as a bedroom does this fit into the regs requirements?

 

[If in doubt...]

Out of interest, at what point are building regs and planning permission required?

If you had a garage you want to insulate and fit a radiator in but one you'll never inhabit as a bedroom does this fit into the regs requirements?

Others may elaborate but generally Building Regs come in to it when you change a room to become a “Habitable” room. Even if you don’t intend to use it as such BC take the view that subsequent owners / renters will and therefore regs will apply at the time of doing the work. Planning is only involved usually if the outside appearance will change dramatically.

 

[noseall]

Out of interest, at what point are building regs and planning permission required?

There are a few building regulations that overlap into the 'you must seek approval by law' category. Thermal reg's and electric reg's seem to be the main culprits as well as a smattering of structural reg's. Compliance isn't all that difficult for an integral conversion. The usual ball-ache is if the gas main runs into the garage.

 

[^woody^]

Out of interest, at what point are building regs and planning permission required?

If you had a garage you want to insulate and fit a radiator in but one you'll never inhabit as a bedroom does this fit into the regs requirements?

Its common for a planning condition to keep a garage as a garage as it counts as an off street parking space, if so, conversion will require planning approval.

Extending the heating system to this new room, whatever it is to be called or used for could be the trigger for b/regs, however the permission would be for the new use not the heating extension.

 

[^woody^]

but generally Building Regs come in to it when you change a room to become a “Habitable” room

Or utility, WC, kitchen, wet room if attached. May not need any permission if detached.