Hi all. I'm converting an old detached garage into an office/man cave and I want to prevent any problems down the road. I'm hoping someone who knows a lot more than me will respond. Here are the particulars:

It's got tin sides and a tin roof.
Once properly wired and insulated I will be getting a mini-split air conditioner/heater installed.

Now for the big question(s):

What is the best way to insulate this without having to remove the siding first?
Do I need a radiant barrier between the tin siding and the batt insulation?
Should I have a vapor barrier?

Thanks!

Spray foam.

Thanks! I've actually looked into that. Should I do open cell or closed cell? Is this something the average person could do a decent job of, or should I hire a pro?

you can glue 1" blueboard to it and get all the insulation you will need, dbl it if ya want to.

much cheaper than blown foam.

use a polyurethane construction adhesive and tack some #3 soffit nails into the studs to hold it while it dries.

buy it at the local box store ie. lowes etc.

https://www.lowes.com/pd/Dow-Common-1-in...rier/1000168163


if you glue this to the metal, add vapor barrier behind the sheetrock you will actually increase your R value with a dead air space. just be sure to not penetrate the barrier any more than you have to.

or use this for a barrier, tape the seams.

https://www.lowes.com/pd/Kingspan-Insula...ation/999972970

Thanks!



And thanks again!

"just be sure to not penetrate the barrier any more than you have to."

I hear that from my wife all the time.

ohhhhh, if it just would not get me a vacation!

Not sure on the type. The installer will know. It will have to be done by a pro.

There is a company..can't remember the name.....that will rent you the equipment and a hand to diy.

I would walk the building and hit it with the gap filler insulation foam you buy at Home Depot to cover any drafty areas. If you do decide to spray foam the building make absolutely positive your electrical is squared away. That stuff is such a pain to work around in residential jobs.

Without a moister barrier spray foam is I no no.

By the looks of the pictures, water leaks have been a problem in the past.

Seal all water leaks (if any) and install a rigid insulation.

Good luck.

That's not true. They spray foam shops all of the time. Right on the metal.

You are wrong again.

Google spray foam and moisture problems.

On a new roof with no leaks, it's not a problem. He has an old corrugated tin roof and walls. ( no lap screws, seen.)

Btw, how is your patio roof shedding water with the R Panel ridges running in the wrong direction on half of the roof, with a valley in the corner and not enough slope?

Yes, shots were fired! Any boat ramp, any day.

one thing that will help that roof a lot is some koolseal in white.

I used it on my trailer at fork in 2005 and it is still in great shape.
also what we used on gpas trailer when we sealed it, have not heard a complaint yet.

it is water clean up and dries to a rubber like finish, mine is about 3/16 thick.




https://www.doitbest.com/products/116947