Understanding Step Flashing

[Jadele]

Hi Guys, Can someone help with this issue I have? I am building my conservatory and need to flash the roof with a step and cover flashing. I think I know what I am doing but something niggles my mind. Logic suggests that water will run down the flashing face to the angled return parts. It would then run down the angled edge to the corner that is on the course of brick below. Whats to stop the water simply going behind the flashing at this point? I attach a picture to show the path I imagine water will take (Mine is step and cover but this pic shows what I mean. Any help on understanding this or what I need to do to stop it happening appreciated.

J

 

[datarebal]

I could type a load of blurb about most step flashings are not totally correct...... but wont... for now, google chimney trays, cavity trays etc

 

[Jadele]

I already know about all that but in the example pic (and I no intention at all of using cavity trays to weaken the wall) they are not used and the steps are done with a single piece of lead even the soakers below would not stop ingress of water in the pic as it would run behind them too. Is it purely that the lead is close to the wall so very little gets past.

 

[catlad]

I have had the same thought myself but I have
never known it to be an issue.
That said in an area as sensitive as yours it would
be wise to use individual flashings.

 

[Notch7]

Or you could do a cut parallel to your connie pitch and put in a straight flashing......no step joint worries that way

 

[catlad]

Except for gamble of not bothering with cavity tray's

 

[Notch7]

Except for gamble of not bothering with cavity tray's

Thats certainly true.

The gamble depends on the situation of course........

 

[datarebal]

I already know about all that but in the example pic (and I no intention at all of using cavity trays to weaken the wall) they are not used and the steps are done with a single piece of lead even the soakers below would not stop ingress of water in the pic as it would run behind them too. Is it purely that the lead is close to the wall so very little gets past.

Oh right ! now we know.
If you know this then what are you actually needing to know.

And as Catlad quite rightly says no trays = gamble

Trays, pick up moisture within brickwork and will also pick up moisture that has passed poor flashings.