Deck above garage roof?

[iDIY]

Hi guys,

Many years ago, my steep slopping rear garden had a 2mtr retaining wall built into it creating a flat area to take a garage level with a rear access dirt track. So effectively the prefab garage was below the ground level of the house. Previous owner then built a raised fenced deck above the garage, meaning the deck was actually at garden level.

I have demolished that, put in proper foundations and a dense block garage instead, bringing me to the roof / deck.

I have done a couple of rough sketches (attached). What are people’s thoughts on creating a roof/deck area as shown?

 

[catlad]

A piece of timber 8x2 timber across the edges to square it off would help the walls with no returns will be weak depending on how tall, apart from that it looks ok.

 

[iDIY]

A piece of timber 8x2 timber across the edges to square it off would help the walls with no returns will be weak depending on how tall, apart from that it looks ok.

Thanks, the sketch was deliberately over simplified to show how the roof in question is located between 2 walls as opposed to on top of them, the key picture is the 2nd one showing the proposed construction of the roof/deck. In reality the whole building is 2 stories in places, L shaped and constructed with dense block cavity walls and ties, certainly no weakness issues when you know the full construction.

 

[catlad]

I would bash the metal sheeting at the edge where it meets the wall to form an upstand even if its only an inch.

 

[iDIY]

I would bash the metal sheeting at the edge where it meets the wall to form an upstand even if its only an inch.

God tip, I’ll do that.

 

[Leofric]

The corrugated metal sheeting is spanning in the wrong direction in relation to the joists .

 

[iDIY]

The corrugated metal sheeting is spanning in the wrong direction in relation to the joists .

the joists have to go that way because the span the other way is over 5m. The roofing sheets have to go that way because the fall and guttering have to be at the wall supporting the joists. And if the roofing were layered across the joists rather than inline then the decking above would crush the roofing. So whilst it’s not the ‘conventional’ way, the layout and location restrictions mean it should work fine

 

[Leofric]

And if the roofing were layered across the joists rather than inline then the decking above would crush the roofing.

I realise I am not answering your question about the flashing but why would the decking crush the corrugated roof sheeting