Is a splashback needed if water leakage is not an issue?

[frankeman90]

I am going to build a shed against the garage wall and am uncertain about the slope of the shed's roof -> garage wall.

The project: Shed 1.6 m high, 4.5 m wide, 1.3 m deep. It will have open slats as walls. Nothing moisture-sensitive will be stored there. (Garbage bags, pots, etc.). It will have a sedum roof. First, tongue and groove boards, then underlayment, and thereafter heavy roofing felt as root protection.

I will attach a beam to the wall in the "nail row" - where there is a beam behind - about halfway up the wall. The roof beams will be attached there with joist hangers. Posts will also be laid under the beams against the wall for extra support since a sedum roof becomes quite heavy.

Question: Do I need to install a metal flashing between the shed's roof and the garage wall? It doesn't matter if it rains a bit along the facade. I've read a lot about how this is done with conservatories by cutting the panel diagonally upwards with a groove and inserting the flashing. But there you are aiming for a tight conservatory, and it doesn't matter to me. Or should I install the flashing outside the panel to protect the facade from the sedum roof and not worry about the gaps that arise?

Attaching a picture of the panel.

 

[frankeman90]

... this is how sedum roofs are recommended to be connected to walls. Metal is therefore recommended against the wall quite a bit up.



But the question remains whether it is okay to just attach the metal to the outermost board on the wall?

 

[petererlandsson1194]

I'm not directly familiar with sedum roofs... but I would let the metal sheet extend outside the covering panel so there is some air in between since it's still considered "outdoors" underneath according to your description... however, you might regret it one day and want to seal the storage? It sounds like a smaller extra effort to do it right now and more or less impossible to do well with a fully grown sedum roof?

 

[Rickard.]

You should definitely, as you're considering, have a substantial sheet to protect the facade against the vegetation. Then, whether you want to make it completely sealed or are satisfied with almost sealed, only you can answer. If it's near an eave, it probably won't rain in, but then the sedum might also have trouble getting enough water.

 

[frankeman90]

Thanks for the reply!

I think I'll raise the ceiling by 30 cm (to picture of the mounted board). This gives space to lift both the roofing felt and metal under the overhang of the upper panel.