For fun, here are some schematics of a few gyms I’ve had a hand in.
The one with the orange cross (a Sorinex J*Squat) is mine. Its evolved over 15 years. The smaller one with the red dot walls is an example of smaller but very functional and how one might do a strength area and a cardio / stretching area. The large one is a gym I designed for a friend who is going all in on a large “home” gym which he will share with friends and family.
For me, the cores of a home gym are:
(1) Barbell area with some sort of support system. Having had various types (stands to full cage), we settled on a half rack. It’s more than safe for the weight we can move and also allows attachment of things like a dip bar, pull up bar, TRX anchor point and has weight plate storage. A barbell, plates, bench and some bands, dumbbells and kettlebells was the core of our gym for a decade-plus.
(2) A functional cable column (FCC) or functional trainer (FT). The FCC/FT may seem like overkill for home use but these allow a ton of movements in controlled (safe) fashion. A high quality (like Sorinex) FCC will run $2500. It can also serve as a Lat/Row station. Legend Fitness offers something called the Fusion 3 module which is an FCC attached to a half-or full rack. Great option for limited space. A good Functional Trainer (Legend Fitness, Rep, others) will run $4,000 or so. Buy once and this is a lifetime piece of kit for home use.
No matter what you do, spend some time with pen and paper and really think about what types of training you want to do. Always leave room to move around in the gym. Also, much like bicycles, invest in contact points. What you touch, what you sit on matters. Weight is weight but the contact points matter.
Finally - if you shop around at gym liquidations or used equipment dealers there are some bargains on specific machines. You need to be able to move heavy stuff (shipping is costly on heavy and bulky items) and learn how columns and stacks go together. But its all simple stuff.
Extra Finally on edit - Gym equipment can be bulky and awkward to move. When building a gym space it is worth thinking of how you will get stuff into and out of your gym.
Cheers and hope the schematics are useful as you plan out your space.
My Basement Gym (which includes a small bike shop area):
Big Gym for a Friend and His Family (being built now):
Small but Sweet Gym with a strength area and a cardio / stretching area: