How to insulate this outbuilding?

[jeff5may]

My cousin-in-law has a detached garage he wants to insulate. He has commissioned me to help and provide guidance. I need some expert opinions on how to approach this task, as the job at hand is rather strange.

The building is around 500 square feet, and originally was cinder block walls with a shingle roof. He had a garage door on one end. There was a drainage problem on his property where the rainwater was entering one side of the garage door and finding its way under the block wall on the other side. Eventually, the water undermined his footer and that corner sank, step-cracking the block wall and throwing the garage door off track.

The drainage issue was repaired, but the damage to the building was done. He and a few buddies jacked up the low corner, took out the block wall where it was damaged, poured a new footer, and built the garage-door side and the damaged block-wall side up again. Only this time, the repaired section was erected like a pole barn. The footer was re-poured, posts were set and tied into the existing roof, and the entire building was wrapped with steel siding. The garage door was deleted, and a steel slab door was installed in the uphill corner. While they were at it, the old shingles were torn off, new roofing felt was installed, and a steel roof was installed over horizontal purlins.

When I came over to look at his garage-shed, the first thing I looked for was housewrap or some sort of vapor barrier. Guess what? They didn't put none in. OOPS. I started to suggest re-doing the siding with tyvek underneath, and he wouldn't hear it. Whatever gets done is going to happen on the inside.

I was in there last week rewiring his electric service with a proper renovation panel that runs 220, as a previous jack-leg had the whole building running off a single 15 Amp 110 circuit, which previously served a well pump. He is lucky the place didn't burn down, as the original disconnect had pennies installed under the glass TL fuses!

Anyway, the reconstructed side gets afternoon and evening sun and acts like a hot plate, heating the entire interior to 110-120 degF on a sunny day. I hung a tarp from the roof gutter outside and put a 5000 btu window a/c in the first day I was there. Those two measures helped out immensely in staving off the summer sun.

He is a tool maker by trade and is maybe 8 years or less from retiring. He also does woodworking/cabinet/birdhouse building for hobbies and wants to put a drill/mill and a lathe and...and... in the building and use it for a tiny job shop. Climate control is imperative, as is running water. He is not a mechanical engineer, he is the go-to guy on the shop floor that just makes what the engineers can't figure out how to build work. All the planning and design work is being pushed my way.

What materials and methods would you all suggest to get my buddy a garage that doesn't cost him an arm and a leg to heat and cool? I mentioned a heat pump and/or solar-assisted solution and he is open to something in that direction.

Pics to follow....

EDIT: Pics of outside


Front door, garage door removed


Repaired wall, painters took down the tarp


Original rear and uphill side, wrapped with steel


Repaired footer with post bottoms showing