Possible to run extractor ducting through warm roof insulation?

[ectoplasmosis]

We're building a ground floor extension with a warm flat roof, 170mm insulation above the joists.

 

Due to proposed hob location, I'm wondering if it's possible to run extractor ducting through the layer of insulation in the warm deck, as per the attached sectional photo...

 

 

Edited November 10, 2023 by ectoplasmosis

[George]

Risk of a cold spot as it looks like you need to run it some distance.

 

Would an adapter to a rectanuglar duct make it fit better?

 

Otherwise just used a recirculating hob extractor with an standalone humidstat controlled extractor located in a more convenient location.