Fascia depth (warm roof)

[MB.]

Good morning guys and girls. I hope we all had a good Christmas!!

I am planning my warm roof 'flattie' and would like some opinions on fascia depth if you don't mind.
At what point does a fascia start looking too deep?

For instance, I will be having 225mm joists, 120mm insulation plus decking board etc, which will be over 380mm in total!

I was thinking of cutting 175 off the joists (once they've passed their bearing), leaving 50mm, plus insulation and boards will be just over 200mm. Is that still too deep?
I'm going to use rubber roofing so can 'lose' a bit on the eye with the 60mm edge trims.

Also, what does the top of the fascia fix to? The bottom will be onto the joist, but at the top is just 18mm deck or insulation... do I need to fix some kind of batten along the underside of the top deck?

Thoughts?

Thanks

 

[Leofric]

A stepped fascia !

 

[MB.]

A stepped fascia !

Thanks for taking the time to reply.

Can I ask what one of my questions you are referring to?
I’m unsure what a ‘stepped fascia’ is.

Thank you.

 

[noseall]

‘stepped fascia’

Here's one we did earlier,,,,,

Untitled

• noseall
• 3 Nov 2014
• 2

Untitled

• noseall
• 3 Nov 2014
• 2

Untitled

• noseall
• 5 Nov 2014
• 1

Untitled

• noseall
• 5 Nov 2014
• 1

 

[Leofric]

This is a bit like the sort of simple stepped fascia profile I meant . Reduce the depth of joists by notching out the bottom as you suggest once they pass the wall plate ,then form the fascia in two pieces to reduce the visual impact , so you could have 100mm upper fascia , step back 75mm then down 100mm for the lower fascia, for example. Doesn't have to be prefabricated ,a joiner can easily form it on site.

 

[^woody^]

With fascia, it is one thing where size definitely doesn't matter.

200-250mm max is something to aim for.