Do I need soffits?

[cdbe]

My 1930's house doesn't have soffits, just the rafters with timber fascias nailed to the ends and tatty uPVC overclad . My new extension is joining the existing roof (which will be recovered with breathable membrane and flat concrete tiles). I was/am going to fit grey uPVC fascias and soffits to the extension and overclad the existing timber fascias, which are in sound condition, with uPVC to match. I was also planning to add soffits to the existing roof to match the new part but then started wondering whether I need any soffits at all.

The house has been fine without, no issues with birds or insects, and it's very hard to tell from the ground that there's no soffit.

Do I need to spend hundreds and have a load of messing about fitting soffits anywhere for no apparent reason?

 

[Alastairreid]

Your brickwork will need to go up between the trusses if you are having an open rafter design.

 

[cdbe]

Thanks, that's good to know. I'd already started to infil between the rafters round the other side and the cavity insulation will "fold over" onto the wall plate to prevent any gaps.