How to Value a Ductwork Fabrication Shop in 2026

Ductwork fabrication is one of those quiet B2B niches that most people never think about — until they need sheet metal for a hospital buildout or a mid-rise office retrofit and realize there are maybe three shops in their region that can handle the volume. The businesses are unglamorous, capital- intensive, and almost entirely dependent on HVAC mechanical contractor relationships. And that combination makes them interesting to value.

I've walked through several fabrication shop transactions, and the valuation math is different from installation-focused HVAC businesses. Here's how it actually works.

The SDE Multiple Range

Pure ductwork fabrication shops — the ones that build spiral duct, rectangular duct, fittings, and custom sheet metal components for HVAC contractors rather than installing on jobsites — trade in the 2.5-4.0x SDErange. That's lower than field-installing mechanical contractors (which typically run 3.5-5.5x SDE) for specific reasons: fabrication shops have concentrated customer bases, significant equipment capex, and limited geographic reach.

Where you land depends on customer diversification, equipment age, and whether you've developed any differentiated capabilities — certified welders, specialty alloys (stainless, aluminum), acoustic-lined duct, or cleanroom-grade fabrication. A $500K SDE generic fab shop with three main customers sells at 2.5-3.0x. A $900K SDE shop with 15+ active mechanical contractor accounts, a certified welding program, and stainless capability can push 4.0x SDE.

Above $1.5M EBITDA, strategic buyers — large mechanical contractors backed by PE, or platforms like Comfort Systems USA, EMCOR, or API Group building vertical integration — occasionally acquire fabrication capacity at 5.0-6.5x EBITDA. These are rare but possible for the right shop.

Customer Concentration: The Dominant Risk

Here's the thing buyers obsess over in ductwork fab: who are your customers, and what percentage of revenue does the top 3 represent? The economic reality of this business is that you sell to a small number of HVAC mechanical contractors in your region. If you're lucky, you have 15-20 active accounts. If you're typical, you have 6-10 with two or three driving the majority of revenue.

A fab shop where the top customer is 40% of revenue is facing a full multiple discount — expect 2.0-2.5x SDE instead of 3.5x. A shop where no customer is above 15% and the top 5 are under 55% will command the top of the range.

The wrinkle: fab shops often have informal exclusivity arrangements with their biggest mechanical contractor customer, sometimes dating back decades. That relationship is valuable but almost impossible to transfer. Buyers know this, and they'll want to meet the key customer during diligence to understand the relationship's durability post-sale.

Actionable tip: If you have 2-3 years before a sale, make customer diversification your top priority. Even adding 5-6 new active accounts at $100K-$300K annual revenue each can move your multiple by 0.5-0.8x SDE, which on a $600K SDE shop is $300K-$450K in additional sale price.

Equipment: What's in a Working Fab Shop

A functional ductwork fabrication shop runs $200K-$1M in equipment replacement value depending on scale and capability. Here's what buyers expect to see:

• Coil line. Engel, Iowa Precision, or Lockformer rectangular duct coil line — $120K-$400K. The backbone of any modern shop.
• Plasma or laser cutting. For custom fittings and complex cuts — $80K-$350K.
• Spiral duct machine. Spiro or Lindab spiral former — $60K-$180K.
• Pittsburgh lock former and cleat bender. $25K-$60K.
• Press brakes and shears. $40K-$150K for a capable setup.
• Welding equipment. MIG, TIG, spot welders — $15K-$75K.

Buyers look past the raw equipment number to condition and workflow. A shop running a connected coil line feeding plasma cutting feeding an automated sorting system is worth meaningfully more than the same equipment stacked in a disconnected layout. The fabrication automation story is real, and shops that have invested in it are easier to scale post-acquisition.

Watch for equipment nearing end of life. A coil line that's been running since 1998 is going to need $150K-$300K of capex within 3-5 years, and buyers will deduct that from their offer.

Sheet Metal Workforce and Certifications

Skilled sheet metal workers are hard to hire. Shops with union labor from SMART (Sheet Metal Workers International) Local 28, 104, 265, etc., have access to larger prevailing-wage projects but carry pension and work rule considerations that matter in diligence. Merit shops have more flexibility but often struggle to find experienced layout workers and welders.

What buyers want to see:

• Certified welders for stainless and aluminum work. AWS D1.3 or D9.1 certifications command premium pricing.
• Stable crew tenure. Average tenure over 5 years signals a good culture and low training cost.
• A foreman who isn't the owner. Same story as every other trade — owner-dependent operations get discounted.
• SMACNA compliance. Shops working to SMACNA HVAC duct construction standards command higher prices because GCs and engineers specify compliance.

Margin Structure and Pricing Power

Fabrication shops live on thin margins — gross margins typically run 22-32%, with material cost being 55-70% of revenue. Steel and galvanized sheet prices move around a lot, and shops that can pass material cost increases through to customers quickly have materially better financial profiles than shops locked into annual fixed pricing.

Buyers dig into your quoting practices during diligence. Do you quote with escalator clauses tied to steel indices? Do you carry material hedges? Are your quotes time-limited? A shop with disciplined pricing practices will get a better multiple than one that has absorbed a 15% steel cost increase over the last 12 months without passing any of it through.

Shop Infrastructure and Lease

Ductwork fabrication requires serious industrial space — 15,000-60,000 sq ft with 20-30 foot clear heights, 3-phase heavy power, overhead crane coverage, dock-high loading, and room for raw steel coil storage. This kind of space is increasingly expensive as industrial real estate has tightened in most markets.

If you rent, the lease is critical. Less than 5 years remaining is a deal-breaker for many buyers because the cost to relocate a fab shop is enormous — you're moving coil lines, recertifying equipment, and rebuilding your shop floor layout. Lock in 10+ years before going to market.

If you own the building, plan to structure the real estate as a separate lease at market rent ($6-12/sq ft NNN in most markets). That's how most fab shop deals actually transact, and it lets you keep the real estate as a retirement asset.

What Kills Fabrication Shop Value

Single-customer dependency. The biggest killer. A shop with a 50%+ top customer will get priced at salvage-plus-working-capital unless the buyer is that customer.

Old equipment with no capex plan. Deferred maintenance on coil lines and plasma cutters comes straight out of the price.

Informal quoting and weak job costing. If you can't tell a buyer what the gross margin was on specific jobs last quarter, they assume you don't know. Implement real job costing before listing.

Bad safety record. Sheet metal shops have real injury exposure. An EMR above 1.0 prices into the deal.

Maximizing Value

• Diversify customers aggressively. This is the single highest-leverage move in fab shop prep.
• Develop a differentiator. Stainless capability, cleanroom work, certified welding — anything that lets you compete on something besides price.
• Install proper job costing. Systems like Key2Act, ComputerEase, or even well-configured Quickbooks with job tracking.
• Get pricing discipline. Escalator clauses, time-limited quotes, material pass-throughs.
• Develop a shop manager. Removing yourself from day-to-day production unlocks a higher multiple.
• Clean up your financials. Reviewed statements from a CPA who understands manufacturing and job costing.

For the full framework, see our business sale preparation guide.

The Bottom Line

Ductwork fabrication shops are valuable, but buyers price them conservatively for good reasons: customer concentration, capex intensity, and limited geographic reach. The shops that command the top of the range have built diversified customer books, invested in modern equipment, developed specialty capabilities, and professionalized their operations. If you own one and you're 3-5 years from an exit, those are the things to focus on — not the next piece of equipment you were thinking about buying.