Didn't build a shop like this yet, but I built my own home in Menifee. Most of my surprises were from the City or County. So most of my input is regarding that.
Just a note, if you are going to demo the existing garage, demo the slab for it as well and pour one new slab for the new garage. You do not want to expand from the existing 1942 slab and have a structural issue with differential settlement.
Things to think about....
- Zoning, what does your zoning allow? Is there a height requirement?
- Demo, city may want a demo permit for your existing garage. I wouldn't even ask or mention it... it mysteriously vanished over the weekend.
- Soils, city may require a soils report from a geotech if you do not have any previous records of a soils report on your property.
- Grading, typically moving over 50CY's requires a grading plans/permit. If they ask, you have a nice flat area and need to move less than 50CY's. They will still make you OX and recompact to 90-95% depending on what that soils report recommends.
- Structural Slab, prefab company will make recommendations but it will need to be engineered. City will make you get structural plans from a Civil or Structural licensed in the great state of CA. Usually a separate cost outside of the plans you get from the prefab company.
- Electrical, I would say it does not have any electrical to avoid getting engineered plans for electrical. Can always be added later after receiving final inspection.
- Plumbing, if you want a sink or shitter in there, you will have to submit plans for it. If you are on septic, it may be an issue depending on the size of your septic system. If its too small, they may make you expand your leach field. This opens up another can of worms with the county as you will need to recertify your system. Regardless, they will want to make sure its sized correctly.
- Fire Protection, it will most likely be required now with the new CBC if your are trying to submit on a legit garage. Another set of plans that will be needed from a licensed FP engineer.
As for the style of structure:
The garage you are thinking of going with is a prefab system. Made with light gauge framing materials and self taper screws. Its great for carport, RV covers etc. Material is easy to work with and goes up quick. If you want it to be climate controlled, you need to make sure the exterior has a vapor barrier and proper attic ventilation in order to insulate it. If done right, you shouldn't be able to tell the different if it were stick built or prefab light gauge framed once drywall is up.
I would make sure you go through an installer and not directly with the manufacturer then get an installer. That way, if anything is missing from the kit, it is on the installer and not you. I would try to find an "owner builder" installer. They take more pride in their work and are typically a lot better to work with.
Maintenance wise.... I do not see it being any different that any other structurer. Especially being metal and not wood.
I have thought about doing one of these myself. One thought I had to help get through all the red tape was to start off by getting a permit for a "carport" or AG building. Same size structure with only (3) sides and have it sit on a curb on top of footing and the floor be rock or dirt. Get that built and get the city out of my hair. Once they are gone and its been a good minute, install UG utilities, pour a garage slab and build out the 4th wall with my garage doors, rough-in electrical insulate and isntall interior wall coverings. City or county wont know from GIS imagery the difference.
