Advice needed please on ducting

[massf]

Hi there

new to the forum and wanted to ask some advice please.

I'm looking to replace an old concertina pipe from the pump that feeds the shower fan. Iin order to vent the steam out correctly in the shortest run, I have to run a conduit down through the eaves (this being done in the loft) and cut a hole in the soffit externally and fit a vent plate.

The problem is that I only have clearance in the eaves for approx 40mm pipe, so my question is, can I get a 40mm to 100mm round pipe adaptor?

Thanks in advance

 

[noseall]

use flexi hose then flatten it a bit.