Should rear garage extension have a sloping roof?

Question

Hi,

Just chasing some opinions on some designs my draftsman has done up for a small rear garage extension to act as a bit of a workshop.

He has the roof sloping to the property boundary, and although it is only at 2 degrees over 3.6m that will be roughly a 130mm difference in height between the house side of the roof and boundary side of the roof. I was concerned this may look a little funny when a single roller door goes up? Will the sloping roof look odd against the level roller door? I’m assuming there will be a level timber header there so might not look so noticeable?

Or I can ask him to change the design so it slopes 2 degrees towards the rear of the property is level from right to left. He already said he can do either option, it’s up to me. I’m just struggling to picture the whole thing in my head.

What do you guys think?

EricL · Answer

Hello @bigkid

This is definitely a question for your draftsperson. You could always ask them about the safety and security of the structure. I don't wish to second guess your draftsperson's plans. Perhaps there are details we are not seeing in the plans.

Eric

bigkid · Answer

Hi @MitchellMc, thanks for the input.

Having another look at the plans I noticed this odd intersection with the rafters not actually sitting on the top plate of the wall, due to the zero lot gutter.

Does not seem to be the most structurally sound way to tie the roof frame to the wall, what do you think?

MitchellMc · Answer

Hi @bigkid,

I don’t think the slight side-to-side fall will be a major visual issue, especially over that short span. It’s only about a 130 mm difference, and with a level header above the roller door it will likely read as straight to the eye. Most people wouldn’t notice it unless they were really looking for it. That said, it does come down to how particular you are with symmetry. If you’ve got the option, a front-to-back slope is often the safer choice visually, as it keeps everything looking level across the face of the garage. It also has the practical advantage of having the gutter at the front, making it much easier to access and clean compared to having it tucked along the fence line.

Alternatively, you could add a flashing to the roofline to obscure the elevation change.

Let me tag @Dave-1 and @Nailbag to see if they have any thoughts.

Please let me know if you have any questions.

Mitchell