Garage conversion

[aaron1987]

I am moving through the new house I have bought. The next thing I'm planning on doing is converting our garage into a playroom for children. Thought I'd run my ideas through here see what people's views were, especially with regards to heating and floor.
Here's a summary of garage
The garage is connected to house by kitchen door, it has big flip door on front, single skin brick, concrete floor (about 200mm lower than floor in kitchen.
My plan is to remove garage door and brick up half way - then install a large window. I was going to put a stud wall where it is only single skin, using the steel studding and rigid insulation rather than timber studding to avoid cold spots, then the same with roof (stud and insulate)
Then with the floor I am not sure whether to insulate and screed, put in joists and insulate, and also whether or not to install underfloor heating.
What are people's views on how warm they think the room will be, any ideas on what size insulation to use, whether you think I need underfloor heating or would get away with insulating and a radiator?

 

[noseall]

The whole 'science' regarding insulation in various parts of a house is based upon how well insulated the existing structure is and how it is built. As long as you strive to achieve the correct standards then building control will be happy

A floor would typically have either 125mm of 'jablite' or 80mm of celotex type insulation. But, as far as garage con's are concerned, building control will accept whatever you can get within the space you have and will not insist upon you digging up the floor.

A solid 225mm (1 brick thick) wall would need say 50mm of celotex added to it to bring it up to scratch.

Similarly a half brick thick wall would need say 125mm of celotex insulation integrating into a stud wall etc.

The wall at the front i.e. the one replacing the garage door could be built conventionally with 105mm brickwork, 100mm full-fill dritherm cavity and 100mm lightweight block internally.

Finally, if the garage is not integral, or if there are roofed parts sticking out, then these will need to be insulated accordingly i.e. 300mm fibreglass wool in the loft space or 125mm celotex warm deck to any flatties.

 

[aaron1987]

Thanks for all that info!
So you think if u stick to the guidelines that the garage will be warm enough without having underfloor heating? I just didn't want to put in all the work to then not have a usable warm room at the end! Lol
It's going to be a playroom for the kiddies you see.

 

[noseall]

Basically yes, you fit enough insulation where you can.

An adequate sized radiator is important and one that works properly.

Building robustly i.e. keeping draughts to a minimum is also very important as is having a well fitted window.

Underfloor heating will make playing on the floor more comfortable and pleasant, whilst maintaining an ambient temperature. However a decent rad will give you the oomph you need on extremely cold winter days.