garage conversion question

[scaredpassenger]

Hi everyone, I'm in the process of planning a garage conversion on our property, just for clarification its a 4 bed detached home, all exterior walls including garage are cavity walls.

Currently our garage flooring sits around 180mm below that of the floor in the hall which is adjacent to it, the doorway into the garage will be entering in from this hallway and I would prefer if the garage floor was level with this hallway floor (though from reading building reg's, it doesn't appear to matter if there is a step down in to the garage)

Is there a way of raising the floor to this level with possibly introducing a 2"x 6" (38mm x 140mm) framework sitting atop a solid or liquid damp proof membrane straight on top of the existing concrete garage floor, with kingspan or similar insulation between the beams, then topping this framework with a solid 30mm wooden floor

Does this sound acceptable? the wording on the planning portal website is whats led me to this question as on one hand it makes it sound like the above is acceptable, and on the other hand there is a part where it mentions there must be a 150mm void between the floor and the beams.

any help on this mater would be greatly appreciated

 

[DevilDamo]

Converting a garage to habitable accommodation would require the elements (i.e. walls, floors, roof) to be thermally upgraded. All elements would require insulating and you may find the existing floor is concrete so you could just lay insulation and screed over in order to provide the level threshold at the door. The step down approach is only required between a garage and a dwelling... not if you convert the garage to habitable accommodation.

If you find you can only put a certain amount of insulation in the floor so you don't compromise the door threshold, you can compensate in the walls/roof, but this would require advice from the Building Control Officer.

 

[scaredpassenger]

HI DOH

whilst I'm sure i could do as you say with the screed, my reasoning for the wood frame work was just that i can do it myself, simply and in my own timescale.

All i want to know is can the frame sit on top of the original garage floor, but thank you very much for your response

 

[tony1851]

You don't say if there is a dpm under the concrete garage floor.
If it's a new (ish) house, there's every chance there could be. In that case theoretically you should be OK with the frame directly on the concrete, and even better if the frame is on a separate membrane.

But some little niggling thing tells me to be careful here - or maybe I'm unduly pessimistic; see what others come up with.

 

[scaredpassenger]

Hi Tony (great name by the way....... Guess what my name is.... Lol)

I haven't checked if there is a dpm in the original floor and I don't want to be smashing the driveway or garage floor up to find out. So just thought my inclusion of a new dpm was going to cover all angles, the house is 40 years old this year (happy birthday house!!)

To be honest the bit that really grinds my gears about converting the garage isn't the time or the money on the conversion, it's how much just getting building regs certificate is! Bloody near on £250 just to say yay or nay to my conversion is a bit of a kick in the balls!

 

[tony1851]

Hi Tony (great name by the way....... Guess what my name is.... Lol)

Desmond?.....

 

[scaredpassenger]

Bob!! Lol

 

[DevilDamo]

To be honest the bit that really grinds my gears about converting the garage isn't the time or the money on the conversion, it's how much just getting building regs certificate is! Bloody near on £250 just to say yay or nay to my conversion is a bit of a kick in the balls!

In the grand scheme of things of what one would pay to convert their garage, application fees are minimal. I assume you have checked to make sure the conversion doesn't require Planning approval? Also remember electrics have to be carried out by a certified person and a certificate presented upon completion of the works, etc...

 

[scaredpassenger]

well yeah if your paying for a company or builder to do it for you, I can understand it would be a drop in the ocean, but for a self converter, like myself, its about 25% of the total conversion cost!

I've already spoken with planning and building reg's at my council, no planing permission needed, but building reg's are and will have to convert under a building notice.

anyway thats enough of my moaning, anyone else got a thought on the flooring situation?

ta

 

[whistler]

Having just completed a garage conversion and studied various methods of raising the floor, I think in your case a option would be to lay compacted sand to level the floor as it will probably have a slope towards the door. Then lay a damp proof membrane, then cover with at least 75mm insulation, then floorboard. Vary the depth of sand and insulation to get your required height.

If you have a suspended timber floor, you need 150mm airspace below the joists but as you only have 180mm then that doesn't appear to be an option.