Insulating Cathedral ceilings

https://baileylineroad.com/cathedral-ceiling-insulation/

This has great information

I've been wondering about this. Thanks for sharing. I have a garage with open rafters and, shocker, it had moisture problems. I ripped out the moldy insulation bats and want to redo the insulation, so I think I'll look into doing that closed cell spray foam.

Sam, I am glad your saw this in time, I was surprised at the simplicity of the fix also.

Basically the solution is to spray foam the rafter bays (putting video here for easier access):

What did people do before spray foam?

stiil air space
seaweed
cork
newspaper
rockwool
sheeps wool
polystyrene sheets

So did all of those options cause problems with moisture? Or were they just less efficient? Or both? I like the idea of using something more natural than spray foam.

I believe they worked IF done correctly.  

If you can keep warm, humid air from the house from entering the insulation, you won't get moisture problems.  Now we have plastic film, often called visqueen here in the US, that will keep the inside air inside the house.

In the olden days they didn't have a way to seal a house so it was drafty.  Maybe deliberately drafty?  Any moisture in the walls would be able to wick outside along with all the air blowing in and out of the house.  Yay, no moisture problem.  But it was very cold inside...

A person could do a very good job of insulating a cathedral ceiling if they put rockwool or some other good insulator in the rafter bays and then cover it all up with plastic film before putting on drywall or paneling.

Great information, thank you!

Mike Haasl wrote:

A person could do a very good job of insulating a cathedral ceiling if they put rockwool or some other good insulator in the rafter bays and then cover it all up with plastic film before putting on drywall or paneling.

Sorry, I can't watch the video to see what the ceiling was like before the spray foam. Is what Mike described not the standard way to do it? Are people typically doing other things in their cathedral ceilings that cause problems?

I'd be leery of spray foam, myself. If your roof leaks, the spray foam will keep the moisture in your roofing material and you might not know you have a problem until your roof rots out.