Thinking of converting external garage to office...

[Iknowcraig]

hi all, long time lurker but this is , first post. I have an external single garage at the end of the garden which I would like to partially convert into an office to work from home in. I don't plan on bricking up the garage door or anything as I would like to keep the front half as garage and simply partition it down the middle with the rear as an office.

There is already a side door into the garage which I plan to keep and then have an internal door into the garage. I would ideally like to add a window or skylight in the office section to have some natural light.

I would like to do all the work myself and as cheaply as possible whilst making a nice space to be in. What I would like to know is what would be the main requirements to make this a decent room; specifically:

Damp proof course - is this easily achieved by laying down damp proof membrane then just timber on top for floating floor and timber stud work for walls?

Window/skylight - if I install a side window do I need a concrete lintel above? How easy is this for a diyer?

Building regs- do I have to adhere to regulations or could this be achieved cheaper and still to a decent standard if I am not bothered about resale compliance? It's as likely a buyer would want to rip it out and just have a normal garage as they would keep it so is it worth going to lengths to meet compliance standards or just build a non compliant room? Would this cause any problems other than for resale?

Insulation & ventilation - what will I need to create a comfortable room? I hate being too hot in summer and get hayfever so will likely install a split aircon unit which should be able to both hear and cool?

Internal door to office - will a standard wooden door suffice?

Power - the garage currently has power but based on the dodgy diy wiring in the rest of the house I don't know where this is taken from, possible as a spur from the kitchen ring main I think. How should I get power there? I have a spare space in the house consumer unit previous occupied by a power shower. Would I run armoured cable from the house consumer unit to a small consumer unit in the garage?

I'm sure I'll think of more but the above seems like a good start! I have our first baby due late July so am hoping I can do the conversion over the next couple of months so I can work in peace once he/she arrives!

Thanks!

 

[theprinceofdarkness]

Building regs are to provide a habitable and safe enviroment to live in. If you want to work in your office wearing a great coat and hat, or if you want to spend £1 an hour on heating , ignore them. Having said that, its best to call the change an insulated workshop, then you can officially ignore them, but conforming as and when it suits you.
So you must install insulation, keeps you warm in winter and cool in summer, 4" of Celotex would be OK, all over all the walls and ceiling and it should be under the floor, else you will get cold feet.. A single skin wall can not be relied on to be 100% watertight, so the wall should be waterproofed.
New armoured cable would be a good idea, as would be a new mini consumer unit with a RCD, 32 A and 6A MCBs, for your lighting and power.
what is your roof construction? This will affect the requirements for a ceiling and your added window and if you need a lintel.
Frank

 

[Iknowcraig]

Thanks for the help, in terms of waterproofing, what is the best way to go about this? Is it using a damp-proof membrane between the timber studs and walls?

In terms of floor - I have read some people just lay down insulation boards with chipboard floor on top, whereas others use a timber frame with insulation inserted, which is the best option?

I have read that it is best to not have any attachment from the wall stud framework to the wall to avoid cold bridging and instead attach it to the floor/cieling with a gap between it and the wall?

With regards to the window, it appears I might be doing this on a bit of a budget so may leave the window for now but possibly put one in down the road, is there anything I should do with regards to this whilst I am doing the work now to make it easier later?

 

[theprinceofdarkness]

Unlike an insulated brick cavity wall, your Celotex will be bridged by the vertical wooden studs that support your internal wall covering. Providing you do not use excessive sized brackets between the brick skin and your timber, there is not much to worry about. You are not trying to build a "Passiv" house (Germany very low energy house - 3kW of heating on in the winter). I suppose you could be, how thick is your insulation going to be?
If your wood work is good enough, you could build a free standing shed inside the garage then there would be no thermal bridging at all. You pays your money. . . . .
Frank