Hello all, I am a cautious home owner — not a pro.  We recently bought a 1950 home in humid Tampa, Florida area.   It had a 22 year old HVAC, nasty attic insulation and a crawl space in need of attention.  We just had all insulation vacuumed out, new HVAC installed (air handler and ducts are in attic. Attic is 5.5 feet tall at ridge and extremely cramped as it meets outer walls.) We cleaned the crawl space out and put a higher quality vapor barrier down last week.  These steps alone have done a lot for air quality inside house.    Next, I planned on having open cell spray foam installed on roof deck.  (btw, everyone does open cell in Florida attics — not closed cell.)  My concern is, I’ve learned that a retrofit spray foam job in an old house can often create downstream humidity headaches?  so now I’m second guessing my initial decision.  Is this problem a 5% risk or a 50% risk??   So many conflicting opinions out there, often depending on what service they sell…  and I’m not what to think at this point.  I’d rather not be forced to run a dedicated dehu in attic as a result of spray foaming attic.  I’d much prefer to put that money towards a ventilating dehu that manages CO2 and humidity in living areas…    When I asked questions about humidity implications, my HVAC guy said  “do the spray foam…monitor for humidity…  respond via dehu in attic, but only if needed… but he couldn’t quantify the likelihood.   I’d prefer to better understand this particular risk.    I put insulation on hold briefly.  I am now questioning if I should just do a really good job air sealing the heck out of attic, air sealing baffles for wind protection and then go with R38 blown insulation (code in Florida).   I’ve learned that R20 foam insulation is the same effective value as R38 blown insulation; as foam is measured on a different scale.   Would folks in this group give open cell spray foam a thumbs up?  Am I overly worrying — as long as I go with a reputable installer, should it work out ok?  One last thing…  a second question, but not as important…  I planned on having hurricane clips installed via soffits (old house, does not have them)… I assumed that had to be done before foaming, as the foam would fill void in soffits.   One foam installer said he had “a system” that would allow the hurricane clips to be installed afterwards. That does not make sense to me, from an exterior air barrier perspective — seems like it would be a crappy foam job, if rafters and top plates are still accessible from exterior soffit?  Does his comment make sense to anyone on here?    I really want to insulate ASAP… but I also don’t want to rush into the wrong decision.  Many many thanks for any advice!