5 Major things that drive up auto body restoration cost
It can be surprising to hear the range of auto body restoration cost estimates. There are definitely a lot of things to consider. Restoring a classic car or truck is a complex process – even if it looks like it’s going to be pretty simple. You should check these 5 things before you start:
Most restoration projects involve at least one of these areas. Many are affected by more than one. The restoration team has to address these issues before any of the body panel, paint, or trim work is done. Together, these things can drive the auto body restoration cost up very quickly.
These issues must be addressed regardless of your restoration goals – whether it is to restore your car to a daily driver, show quality, or concourse level restoration. If you skip this step, your vehicle will not be safe to operate.
It’s not always possible to know the condition of these areas without a physical inspection by a qualified restoration technician. Even then, the true extent of the vehicle’s condition won’t be known until the shop starts taking things apart.
Torque Boxes and Cowls
How a torque box affects auto body restoration cost
A torque box is a metal box or frame. They are usually welded into places where a unibody or frame would flex more than it should.
Torque boxes are commonly used on convertibles because the body doesn’t have an upper roof structure to help prevent twisting. Even though the article is focused on high torque applications, Mancini Racing has a good explanation about different types of torque boxes. However, torque boxes can be used on all cars – whether or not they are convertibles or performance vehicles.
When a major torque box is rusted, bent, or has been incorrectly repaired, it can require a significant amount of time and labor to correct.
How cowl conditions increase auto body restoration cost
An automotive cowl is a place where two sections meet. The section between the windshield and hood is one example. The section between the rear window and the trunk lid is another.
We look at the condition of the main torque boxes and cowls at the same time because they are often the places where water gets in and creates significant rust. This can be especially true if the vehicle has been in an accident and these areas have been repaired.
In most cases, damaged cowls panels will need to be replaced. Depending on the age and rarity of your vehicle, your restoration team may have to fabricate replacement parts if they are not available. Fabrication is almost always the most expensive way to replace parts. Fabrication is only done when the shop has made reasonable efforts to locate quality replacement parts.
Trunk, Floor Pans, and Engine Bays

Before and after photo of a rotted out engine bay pan showing the extent of damage and impact on auto body restoration cost.
Water damage
Since the cowl is the first line of defense against water, we also look closely at the trunk and engine bay. That’s because water usually pools at the bottom. When it does, it will usually rot all the way through the metal. When this happens, the team will have to completely replace the affected area.
Water always travels to the lowest point. As it does, it leaves some water behind. Over time, repeated exposure to water can result in rust. Floor pans are a natural collection point for standing water in classic vehicles with leaks.
If a trunk, engine bay, or floor pan has been rusting for a long time, the metal that’s connected to it will probably also be rusted. Even if it isn’t rusted completely through, the technician may still have to replace it. That’s because any new sheet metal has to be connected to strong body material. The extent of the repair area may cause significant amount of time.
These factors increase overall auto body restoration cost. The shop team will have to replace every area that has rotted or been significantly damaged.
How having a car in a barn might not save auto body restoration cost
A lot of people call and think their auto body restoration cost will be low because their vehicle has been in a barn for a decade or more. A properly stored vehicle can have a significantly lower auto body restoration cost. Most “barn finds” haven’t been properly stored. In many cases, we see complete rust through on trunks, floor plans, and engine bays from cars and trucks that have been stored in barns.
Few barns are rainproof. The most surprising thing many people is learning that moisture from a dirt floor can cause rust. The space between the dirt and the bottom of the vehicle can have a higher moisture content than the air around the car. Over a period of decades, this moisture causes rust. Untreated, it can become a major structural problem.
Rocker Panels

Close up photo of a green Mercedes Benz 280SL rocker panel showing how rust through can increase auto body restoration costs.
The rocker panel is the piece of metal that runs from front to back between the front and back wheels. There is one panel on each side of the vehicle and they form the door jamb. The inside edge of the rocker panel is either part of, or welded to, the floor pan. In some cases, the rocker panel is an integrated part of the vehicle’s structure.
The paint is usually nicked and scratched through normal wear and tear during a car or truck’s lifetime. Compromised paint can lead to surface rust. Left untreated, the rocker will rust from the outside in.
These panels can also rust through from the inside out. That’s because, as we pointed out in the section on Trunk, Floor Pans, and Engine Bays, water travels to the lowest point. Often, a damaged exterior body part will allow water to get inside the rocker panel. Over time (especially if the vehicle has been sitting for a long time), this water will cause rust through.
Rocker panels are important enough that they’re specifically identified in the National Auto Auction Association (NAAA) Structural Damage Policy.
There’s no shortcut around rusted rocker panels. Depending on your auto body restoration cost and project goals, the repair shop may be able to perform a partial replacement. In some cases, this can be just as expensive as replacement because fabrication will be required.
Non-galvanized Metal Increases Auto Body Restoration Cost
Most vehicles produced before the mid-1970s used non-galvanized metal. Hagerty Media has a great write-up about what galvanized metal is and why it’s important in automobile production.
If you’ve got an old classic car or truck that’s completely covered in rust, there’s a good chance the metal wasn’t galvanized.
In many cases, a vehicle with un-galvanized metal will have substantial rust. When this happens, as Hagerty says, there are usually “no easy answers”. Most of the time, the vehicle will require far more effort and cost to restore than most people will find to be reasonable.
A restoration can make sense when there is a moderate amount of rust on non-galvanized metal. The shop will most likely need to replace these pieces.
Structural Rust
We’ve highlighted a couple of key areas where rust and damage can increase auto body restoration costs. There are many other structural areas you’ll want to evaluate as you plan your restoration project. Some of the more expensive repair areas include:
- Unibody welds
- Frame rails
- Body panel mounting points
- Motor mounting points
- Suspension mounting points
- Driveline mounting points
If the vehicle has been driven or stored in a northern climate where snow and ice are regularly present, there’s a good chance you’ll be dealing with an increased amount of structural rust. Similarly, if you’re restoring a classic off-road vehicle used in salty and sandy locations, the level of structural rust will likely be higher.
In either case, the vehicle will required additional parts, labor, and time to correct structural rust before starting any paint and trim work.
About Automotive Collision Specialists in Fuquay Varina, NC
We’re an auto body restoration shop. We can coordinate a full restoration with our vetted partners for mechanical and interior work. Since our main focus is on the body and paint restoration work, everything in this guide is focused on the body and paint work required to perform a quality restoration.
We’ve served some of the best auto body shop customers in and near Fuquay Varina NC! Our work has been featured in magazines and museums. We’ve also done concourse level restoration work on cars that have sold at auction for more than a million dollars. That’s earned us a local reputation – and one that reaches to customers in other states as well as Canada.
The Automotive Collision Specialists team has the experience to help with your classic car restoration needs. Why not give us a call today at (919) 552-0333 and find out how we can help?
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