After years of selling metal buildings, I can tell you the single most common regret I hear from customers: "I wish I had built bigger."

Nobody ever calls me to say their building is too large. But I hear from people regularly who are already thinking about adding on — sometimes within the first year of ownership.

Sizing your metal building correctly from the start saves you money, frustration, and the hassle of expansion projects down the road. Here's how to do it right.

Start With What You Know You Need

The first step is to make a list of everything you plan to store, park, or work on in the building. Be specific:

• How many vehicles? What are their dimensions?
• What equipment will be stored? What are the largest pieces?
• Do you need workspace around the vehicles/equipment?
• Will you have workbenches, shelving, or other fixtures?
• Do you need a bathroom, office, or other dedicated space?

Write it all down before you start looking at building sizes.

Add the Space You're Not Thinking About

Here's where most buyers go wrong: they size the building for what they have today, not what they'll have in three to five years.

Ask yourself:

• Will I add another vehicle?
• Will my equipment inventory grow?
• Will I want to add a workbench or tool storage?
• Could this building serve a different purpose in the future?

Add 20–30% to your initial estimate to account for growth. You'll use it.

Understanding Dimensions: Width, Length, and Height

Metal buildings are described by three dimensions: width × length × eave height.

Width

Width is the most important dimension for usability. It determines how many vehicles fit side by side and how much workspace you have.

Common width guidelines:

• 20 ft — fits one vehicle with minimal workspace
• 30 ft — fits two vehicles comfortably, or one with good workspace
• 40 ft — fits two vehicles with excellent workspace, or three vehicles tight
• 60 ft — commercial-grade, fits multiple vehicles with full workspace

Length

Length is easier to expand later (by adding to the end of the building), so it's less critical to get exactly right. That said, plan for growth here too.

Common length guidelines:

• 30–40 ft — basic storage, 1–2 vehicles
• 40–60 ft — workshop or multi-vehicle storage
• 60–100 ft — commercial or large agricultural use
• 100+ ft — warehouse or large equipment storage

Eave Height

Eave height is the measurement from the ground to the top of the sidewall. This determines how much vertical clearance you have inside.

This is where buyers most often underestimate:

• 10 ft — minimum for most residential garages
• 12 ft — comfortable for most vehicles and equipment
• 14 ft — recommended if you have tall trucks, RVs, or equipment
• 16 ft+ — required for large RVs, combines, or commercial lifts

Always measure your tallest vehicle or piece of equipment before choosing eave height. Add at least 2 feet of clearance above the tallest item.

Door Sizing: Don't Forget This

The building's interior dimensions don't matter if you can't get your equipment through the door.

Standard door sizing guidelines:

• 10×10 — fits most passenger vehicles and small trucks
• 12×12 — fits most full-size trucks and SUVs
• 14×14 — fits most RVs and tall equipment
• 16×16 — fits large RVs and most agricultural equipment
• 20×14+ — for wide loads or commercial equipment

Measure your widest and tallest vehicle or equipment, then add clearance. A door that's just barely big enough is a door that will eventually cause a problem.

A Practical Sizing Example

Let's say you want a garage for:

• Two full-size pickup trucks
• A riding lawn mower
• A workbench along one wall
• Some shelving for tools and supplies

Starting estimate:

• Width: 30 ft (fits two trucks side by side)
• Length: 40 ft (fits trucks plus mower with room to move)
• Eave height: 12 ft (comfortable for trucks)

Growth adjustment (+25%):

• Consider 30×50 or 40×40 instead
• Consider 14 ft eave height if you might get an RV or taller truck

My recommendation: 30×50×12 minimum, 40×50×14 preferred

The extra 10 feet of length and 2 feet of height cost less than you'd expect and make a significant difference in usability.

Common Size Reference Guide

Use Case	Minimum Size	Recommended Size
Single car garage	20×20×10	24×30×12
Two-car garage	24×30×10	30×40×12
Three-car garage	30×40×12	40×50×14
RV storage	14×40×14	20×50×16
Small workshop	24×30×12	30×40×14
Large workshop	30×50×14	40×60×16
Small farm storage	30×40×12	40×60×14
Equipment barn	40×60×14	60×80×16

One More Thing: Think About the Future

Metal buildings can be expanded by adding to the length (not the width). If you think you might want to expand, plan the building's orientation so the end wall faces the direction you'd want to extend.

Also consider: if you ever sell the property, a larger building with a concrete floor and proper permits adds more value than a smaller one.

Let's Size Your Building Together

When you call me at 901-412-1270, one of the first things I'll do is ask about everything you plan to use the building for — now and in the future. Getting the size right is the most important decision in the buying process, and I'd rather spend 10 minutes on the phone making sure we get it right than have you wish you'd built bigger two years from now.