Flat Roof Drainage...

[Mulberry View]

Our scheme has a single Car Port with a 10° monopitch roof which is linked to the house by a walkway with a flat-roof over.

 

This is the roof plan...

 

 

The Car Port is to have a gutter along the low edge, which will drop water onto the Link Walkway roof, which is essentially a flat roof. The water will fall towards the bottom corner as denoted on the plan.

 

From this drawing, I have assumed a kerb is installed at both edges, with the water dropping through a "Plug'ole" before being directed into the adjacent RWP.

 

Does anyone have any words of advice as to how this fall arrangement is organised with firrings? Or can you suggest a better way?

 

I did debate arranging the fall to simply run from right to left and into an integral gutter along the right-hand edge, so in essence the water from the roof above will drop directly into the integral gutter below and the water falling on the flat roof will fall also into the integral gutter.

 

Any thoughts/advice would be appreciated, as always.

[Spinny]

What is the roofing material and how will the underside be finished ?

[Mulberry View]

8 hours ago, Spinny said:

What is the roofing material and how will the underside be finished ?

 

Likely to be a single-ply membrane. I can see the fascias being Aluminium flashings of some sort. The underside needs to be a flat ceiling, though I'm not sure if it can be plastered as it is essentially outdoors...

[Spinny]

is there any case for extending the underground drain over to the carport ? 

Might you be washing the car under the carport ? Would you have use for a ground level drain gully to take ground water running away on any adjacent hardscaping ?

(just wondering about taking the water away from the main building rather than towards it)

 

PS Just looked at your 3d image - seems you do have a hard surface between carport and main building - this would normally run off away from the house - potentially to a ground drain ? Do you plan to have a tap (and electric light & power) to the car port ? Lighting under the walkway ? You could bury the services or take them across inside the walkway structure ? Garden/external lighting planned ?

Edited 2 hours ago by Spinny

[saveasteading]

14 hours ago, Mulberry View said:

Any thoughts/advice would be appreciated

Mine is that we should all do our bit to minimise water use and flooding. So have you plans for water butts?

Also, if your ground can take it, to have your paving drain naturally to ground.

The rain landed there for millions of years and we should try not to rush it away downstream.