Roofing a non square garage

[nitrochicken]

Hi,

I'm about to start building a garage which will have a tiled roof.
My house is on a corner plot so in order to make the best use of the space available, I would like to build it with one side out of square.
This will mean the garage will measure 12 foot across the front and 9 foot across the back.

I'm trying to work out my best options for building/tiling the roof.

So far my best solution is a 4 sided hip roof with no ridge, like a pyramid.

Whilst I think this will work out fine from a tiling point of view, there a few concerns I have with regard to the framing of the roof.

Firstly, where would I place the centre point?
I thought of treating it as a normal rectangular pyramid and working the centre from the mid point of the front and right angled side.
This would mean that the rear rafter would be considerably shorter than its apposing front rafter and at a different pitch.
Would this difference be enough to unbalance the roof and compromise its integrity? Obviously this would then mean that there was more weight of tiles on one side than the other.

My other idea was to build the garage rectangular, with the back corner knocked off at 45 degrees and standard gable roof. The cut up on the rear gable would then continue around the short 45 degree side.
I also think that this would be workable but would lead to some complicated guttering on that back 45 corner.

The pyramid roof is my preferred choice.

Does anyone have any experience of this sort of roof?

I have basic sketchup models of both ideas that I could post if it makes it easier to visualise.

Thanks

 

[freddiemercurystwin]

I have basic sketchup models of both ideas that I could post if it makes it easier to visualise.

yes

 

[nitrochicken]

If you go to the following url, you can download the skp files.
The ones I have mentioned are garage1 and garage2.
Garage3 is another possible idea but I think that would mean too many ridge tiles at the rear of the garage.

The scaling is not accurate, but gives a basic idea of the shape etc

http://sketchup.google.com/3dwarehouse/search?uq=1281125624648891595038166&scoring=m

Thanks

 

[noseall]

A hip roof would have to be built 'in twist' and would be horrendous to build and damn near impossible to tile. Plus, it would look diabolical.

You are going to have to go with a gable roof so that one side of the roof is longer than the other. This does mean that the water run-off on the diminishing side will run down the walls unless you build in a secret gutter at the verge.

My suggestion would be to stagger the building so that the staggers are in 90 degree squared off sections complete with differing wall plate levels etc.
Otherwise you will have to do a wee bit of head scratching and improvisation.