EPDM over existing flat roof felt

[elmsoft]

My extension flat roof consists of: 150mm Jablite bedded in bitumen with three layers of torch on felt over that

I want to just renovate it by covering it with a EPDM membrane. I am not keen to rip that lot off!

But I gather that gluing the membrane over the existing felt is not the way to go and it is advisable to sheet it first with say OSB. That leaves me the problem of fixing the OSB as the joists of course at least 150mm below the surface.
Are there good options here? 10 inch nails maybe?

 

[thirdtimelucky]

Screwfix sell 200mm long number 8 screws.
I would think 9-11mm osb3 would do the job

 

[elmsoft]

And I was only joking about the 10 inch nails!
That certainly sounds a viable option.
Thank you

 

[catlad]

If it ain't broke then don't try to fix it would be my advice.

 

[catlad]

If it ain't broke then don't try to fix it would be my advice.