A basic shed, with just a floor, a door, 4 walls, and a roof will do for many applications, but if you want to really make the best use of your utility building, there are lots of accessories and extras that you can buy, install, or build for yourself.
Lets start with the top. Most dealers offer a vent for air exchange if you want one. Of course, if you have some skill as a handyman, you can purchase and install one yourself. These are usually very simple vents, but you can get a more complex ventilation that you can open and close, or even one that opens and closes with changes in temperature.
Lofts. A loft can increase your space by adding a different plain to your building. They are great for storage, or even as a bedroom for a cabin. They are simple to build, if you choose to do the job for yourself, or the supplier can do the job for you.
Windows. Depending on your sheds purpose in life, adding a window or two could be a great help. These are best added at the factory, but with some skill, and the right tools, you can do the job for yourself.
Air conditioning openings. If you want to add a window unit, but don’t want to use your window to install it, the builder should be able to frame in an opening for you, If you want to do it for yourself, it is no more difficult than installing a window.
Electrical switches and outlets
Electrical outlets may be something you want or need. As in the case of the air conditioning, mentioned above, and the lighting mentioned below, check all applicable codes, and hire a professional when called for.
You might want to add lighting to your shed, and if you do, be sure to follow all applicable codes in your area. Again, some manufacturers offer a basic lighting kit, and a new trend among dealers is solar powered lighting. Many manufacturers will install clear roof panels which act as sky lights. If your building already exists, you can do this for yourself.
While we are on the walls, how about insulation? Most builders will offer it as a matter of course. Your need for this will vary with the purpose of the building. This is also something that you can do for yourself pretty easily. Please be careful when working with fiberglass insulation, wear eye protection, and at least a dust mask. Consider wearing long sleeves and gloves as well. Otherwise it can be an itchy outcome.
Drywall and paneling
Drywall or paneling can give your shed a completed look, but be sure that your electrical work and insulation are completed before going forward with this. If an electrical inspection is required, that should also be done before proceeding with paneling or drywall.
Work benches. If you need work space, or counter space if your shed is to be used as a cabin, a work bench can be installed easily at the factory, or at home using your own materials.
If you have equipment like riding lawnmowers or 4 wheelers, a ramp may be needed. Your shed supplier will probably offer these, and if he doesn’t, building one is simple and easy for a home handyman.
The accessories, add ons, and extras described can all be done by most manufacturers, but this applies to buildings they will build for you. They will probably not want to do this to buildings that already exist on a lot. Some builders may not choose to modify their regular factory models at all. When you do any of these installations for yourself, be sure to follow all local codes, and strive for accuracy when you measure and cut. Just remember to measure twice and cut once.