RV garage or casita? Choosing what to put in the back yard

This comes up more than any other question we get in the West Valley, and it usually arrives phrased as a budget question when it is really a use question.

Both projects start identically: a setback and lot coverage check, a foundation, structural engineering, a permit and, in most of our communities, HOA architectural review. From there they are genuinely different buildings.

The short comparison

Where the money goes in an RV garage

The number that drives everything is door height. A 14-foot door means roughly 16-foot walls; a 16-foot door pushes you toward 18 or 20. Tall walls need engineered bracing, deeper footings, and often a different structural system than a standard garage, and every foot of height compounds through the framing, the roof, the doors and the stucco.

After the shell, the finish decisions swing widely:

• Insulation and climate control. A 1,500 sq ft, 18-foot-tall box in Arizona is unusable in July without it, and the volume means real tonnage.
• Bathroom. Adding water and waste to a detached structure is a meaningful trench and connection cost.
• Slab spec. A coach at 30,000+ pounds on a standard residential slab is a mistake you make once.
• Electrical. 50-amp coach service, a lift, a compressor, a welder or an EV charger all point back at the main panel, which is frequently already full.
• Finish level. Epoxy, cabinetry, a golf simulator, a bar. This is where an RV garage becomes a man cave and the number moves fast.

Detail is on the RV garage cost page.

Where the money goes in a casita

A casita is a small house, and small houses are expensive per square foot because the costly parts (kitchen, bathroom, mechanical, foundation, roof) do not scale down. A 600 sq ft casita has one of nearly everything a 3,000 sq ft house has.

The single largest variable is new construction versus conversion. Converting a garage or existing space starts with a slab, walls and a roof already paid for, and typically lands $100,000 or more below an equivalent detached build. Full breakdown on the casita cost page, and the legal side is in the ADU guide.

How to actually decide

Build the RV garage if

• You own the coach, or you are about to, and you are currently paying for storage.
• You want shop, hobby or toy space more than you want a guest room.
• Your lot has the depth and the access for a tall structure, and your HOA permits the height.

Build the casita if

• You have family who will stay for weeks rather than nights: aging parents, adult kids, long visits.
• You want the appraised square footage and the flexibility that comes with it.
• Rental income is part of the plan, and you have confirmed in writing that your city and HOA permit it.

The third option people forget

Build both, as one structure. Living space above an RV garage is genuinely efficient: the foundation and the structural frame are already sized for the tall bay, so the second level costs less per square foot than a standalone casita would, and you use one footprint instead of two on a lot that probably cannot spare two.

It is not free. Stairs, a second mechanical system, egress and fire separation between the garage and the dwelling all add cost, and height limits and HOA design guidelines are the real constraint. A two-story structure at the back of the lot is exactly the thing architectural committees scrutinize hardest.

But when it works, it is the best answer to this question. Our range for that build is roughly $500,000 to $1,000,000+, and it is some of the most satisfying work we do.