u/BreadfruitGullible63

Hi folks,

I have a 1923 Dutch Colonial Revival and am looking to insulate the the roof of a semi-finished walk-up attic. The basic facts:

1. We have a standing seam metal roof, installed two years ago.
2. Roof was installed with a ridge vent under the belief we had soffit vents. We do not have soffit vents.
3. The roof deck appears to have had past issues with moisture (this was brought up during re-roofing and can be seen in the exposed underside of the roof deck today). I believe the current underlayment is permeable, which I believe is SOP for metal roofs.

The rafters are not to modern thickness, so batting will not provide sufficient R value. Everyone we've talked to says closed cell spray foam. I don't love _adding_ more plastic to my house and I especially don't love how it's effectively impossible to undo. We're a BIFL/low-consumption/energy efficient household and care more about doing things "the right way" than short-term gain; sometimes these goals work together and sometimes we need to compromise. I'm finally coming around to CC spray foam being the right call, but wanted to get a sense of any issues people have had with it, especially if you have a similar setup.

Thanks!

EDIT: I'm looking for your specific stories for CC foam directly on the roofdeck of a century home with similar characteristics, not advice about CC in general (there's plenty of that available on the internet at large). The specific combination of factors is unusual in my area.