Concrete garage roof

[noyk]

Hi,

I have a 12x24 concrete panel garage (concrete post and board type) and i'd like to convert the rear 10ft into a home office. Firstly though i'd like to put a proper roof on it.

It's currently a low pitched roof supported by steel trusses with onduline panels. These are ok but dont look great and are obviously quite drafty, so i'd like some sort of tiles. I'd also like a steeper pitch to increase the internal height and match my house which is 40 deg.

I'm concerned about removing the roof and the thing toppling over, I imagine the corners and steel lintel across the door will hold it up but it's not something i want to chance

Is a higher pitch proper roof feasible on these garages? The steel trusses are currently bolted on to the top of the wall panels, so i was thinking i could remove trusses, bolt some timber along the wall, then put a wall plate on top of that, which would also have the benefit of raising the eaves height a little.

I'm also not sure about the front of it though above the door, should i replace the existing truss or build a new roof over it?

Also does anyone know a ballpark figure for timber trusses for this size roof? I wouldn't mind attempting to build it myself, but if trusses will be significantly cheaper...

Cheers[/quote]

 

[noseall]

Sorry for the unforgiving language but doing what you want to do to a concrete prefab garage is akin to polishing a turd.

The best advice i could give is to build a cell within the garage, i.e. 100mm x 50mm timber stud frame at 400mm c/c, onto which you could pitch your new roof.

This frame could be vapour checked, insulated and plasterboarded and could have a double header to support a new roof. Whether the floor slab is strong enough is another matter, but the internal frame method is the best solution.

Only downside is you will ultimately lose space.

 

[noyk]

fair comment on the turd, i know it's not ideal Are the walls on these not strong enough to support a greater pitch? Why do you suggest full frame? I had considered that as an option, but tbh if i was going to do that I'd replace the whole thing, i dont have a lot of time so was looking for a fairly speedy way to do this.

 

[noseall]

You stated that you want to convert the garage space into an office?

Presumably you want the office to be useable all year round, whilst leaving all the stuff in the office rather than bringing it inside the house come November?

 

[noyk]

You stated that you want to convert the garage space into an office?

Presumably you want the office to be useable all year round, whilst leaving all the stuff in the office rather than bringing it inside the house come November?

Yep thats right, but only about 10ft of the 24ft (at the rear end), i want to leave the rest of it as garage. I know i'll still need to build a frame internally for this section, but i didn't want to have to do that for the whole building, just for the office space area.

 

[PlanningandBuildingRegsMa]

I've been out to a few of these concrete sectional garages where the homeowner want's to convert it to an office / bedroom, and I have yet to find one that would be cost effective to do.

I would consider the option of starting again and having a new extension built from blockwork (cheaper than brickwork) with a flat roof if your trying to keep your costs down.

The one I went out to last year could of been pushed over by a child and the homeowner was convinced it could be converted.

 

[noyk]

Ours is pretty solid at the moment, but will it be if i take the roof off? Thats the question im trying to get to the bottom of

 

[freddiemercurystwin]

It doesn't sound plausible to me at all, I thought the roof steels were tied to the walls and that's what gives the whole structure its 'strength' so removing the steels doesn't sound so great. Also if you raise one side to increase the pitch enough for tiles you're gonna have to infill that bit of wall with something. The whole thing is gonna be a right dogs dinner! Just re-roof the whole thing to stop it leaking and build an insulated frame/ceiling inside as per nosybonks posts.

 

[noseall]

You could build a stud frame inside the whole of the garage but only spec-up a portion of that framing for the habitable bit.

The stud frame could finish say 100mm or so higher than the sectional garage.

The framing could have a double header fitted to the top.

A new duo pitched roof could be fixed to the top of the stud framing on the double header pitching down so that a soffit could be cradled back to the top of the garage sections.

The garage sections could be fixed into the studding or vice versa to stiffen and stabilize.

Surely you weren't going to upgrade the habitable roof bit only and then cobble the two roofs together?

 

[noyk]

hi nose, thanks for the reply. My plan was to replace the whole 24ft long roof and then build a frame inside but only in the rear 10ft or so to make it into a room i can work in.

I was really most concerned with stability because the metal truss appears to my eyes to provide most of the rigidity, if i remove it i would imagine the walls will wobble until i replace the trusses with steeper pitch timber ones (or cut roof).

So probably the main thing is making sure the upper walls are supported properly, so i thought i could attach timber along the top of the walls utilising the fixing holes (i've read it's not i good idea to drill holes as it can fracture the concrete) to fix them and put a wall plate on top of this timber and the walls.

I'm still thinking is this is a viable option, or if i should just sell the garage on ebay and perhaps put up an all timber one in its place. Then i could convert the inside more easily. Trouble is finding a timber garage of that size isn't so easy, and if i had to get a carpenter in to build from scratch it's going to be quite expensive and time consuming.

 

[freddiemercurystwin]

What pitch is the existing roof? I don't understand the obsession with raising the pitch?

 

[noyk]

at a guess about 15 degrees. I'd like it to match the house pitch (40 deg) and the eaves height is currently only about 2100mm so it would provide a nicer space to work in.

 

[noyk]

ok, had a look around and this guy will make to specs and is able to provide whatever roof pitch i ask for, for what seems like a reasonable price. Any thoughts on these -

http://www.ebay.co.uk/itm/LOG-GARAG...Fencing_CV&hash=item19d1e52d91#ht_1072wt_1231

Mine will be 4500Wx7300L

Any idea how this would compare to getting a carpenter in to build one from scratch?

Thanks for any input

 

[noyk]

anyone any thoughts on these timber log garages before i ebay my existing concrete one.

 

[Deluks]

Personal pref. really. Your money though, there are many ways to utilise your existing building as mentioned, of course you would lose space.

Other options could be to get some steel columns made up with a footplate to bolt into the ground. These columns could be bolted to the upright concrete stanchions of the garage, and would be holding the building up.

Or as Nose as suggested, new roof lower truss chord to fly over the existing, then use steel angle, 'C' section, or box section, to bolt the stanchions to the roof trusses.