The GC's Guide to Commercial TI Subcontractor Bidding

Why Commercial TI Bidding Is Different (And Harder)

Commercial tenant improvement work hits different than standard construction. You're juggling tenant requests, landlord requirements, building codes that vary by jurisdiction, and subcontractors who bid the same scope three different ways. The margin between profit and loss on a $200K TI job often comes down to whether you caught that HVAC cutover or missed it.

The worst part? Most GCs are still comparing bids in spreadsheets or email threads. You're looking at five drywall quotes, trying to remember why Contractor A is $8,000 cheaper, and hoping someone flagged that they didn't include fire-rated patches at the demising wall.

The Anatomy of a Commercial TI Bid Package

What Actually Gets Bid in TI Work

Unlike new construction, commercial TI bids are microscopic in scope—but brutally detailed. A 5,000 SF tenant space might have:

• Framing (studs, headers, blocking for everything from TVs to shelving)
• Drywall (standard, fire-rated, moisture-resistant depending on location)
• Paint and stain finishes
• Doors, frames, hardware, and closers
• Flooring (demo of existing, base prep, new installation)
• Electrical (rough-in for new circuits, device boxes, LED fixture installs)
• Plumbing (if kitchen/bathrooms are involved)
• HVAC modifications (usually a smaller scope but easy to miss)
• Millwork and casework
• Ceilings (demo, new grid, tile or drywall)

Each trade gets their own scope document. And here's the problem: scope documents are written by different people, sometimes architects who've never run a shovel, sometimes by you trying to be precise at 11 PM.

Common Scope Gaps That Kill Your Margin

I've seen GCs lose $15K-$30K per trade on TI jobs because of these missed line items:

Fire-rating work. Demising walls, party walls, or walls adjacent to mechanical spaces often need fire-caulk, fire-stop pillows, or fire-rated drywall. One subcontractor prices it, the other doesn't. Now you're on the hook.

Coordination and cutouts. Electrical runs HVAC ducts. Plumbing needs rough-in before drywall. If your bid package doesn't explicitly state "coordinate for all required cutouts and sleeves," you're about to build it twice.

Existing conditions assumptions. Is the existing concrete floor being removed? Is it load-bearing plaster or hollow core drywall? Are there asbestos tiles in the demo area? The flooring contractor bid $3 per SF thinking it's a clean demo, but you've got 1,200 SF of hazmat abatement ahead of the work.

Mechanical rough-ins and testing. HVAC contractors will sometimes bid "connections only" and not include balancing, ductwork sealing, or final testing. You need your mechanical engineer to spell that out.

Permits and inspections. Who's pulling the mechanical permit? The electrical permit? Some subs assume you're doing it; some bid it in.

How to Structure Your TI Bid Request

Step 1: Create a Detailed Scope Document Per Trade

Your bid package should have a cover memo with the project address, tenant name, lease commencement date, and any landlord requirements. Then each trade gets a scope sheet.

For drywall, that means: square footage of new walls, type of drywall (standard/fire-rated/moisture-resistant), finish (paint grade, stain, primer only?), what's included in demo, patch specs, and any special details like curved walls or reveal molding.

Use a drywall scope checklist to make sure you're not missing fire-rating specs, fastener patterns, or finish requirements. The 20 minutes you spend on a thorough scope document will save you 20 hours of change order emails.

Step 2: Be Explicit About What's NOT Included

This sounds obvious, but spell it out. "Drywall scope does not include: coordination with mechanical trades, cutting for future casework, fire-stop installation, or patch repairs after mechanical work is complete."

When contractors read what's explicitly excluded, they know you're organized and they're less likely to bid defensively with built-in contingencies.

Step 3: Request a Line-Item Bid, Not a Lump Sum

A $32,000 drywall bid tells you nothing. But this tells you everything:

• Framing: $8,400 (1,200 LF of studs, blocking, headers)
• Drywall installation (standard): $6,200 (2,400 SF)
• Drywall installation (fire-rated): $4,100 (800 SF at demising wall)
• Finishing (tape, mud, sand): $8,900
• Paint: $4,400

Now you can compare apples to apples with your other bids. You'll spot if Contractor B bid 800 SF of fire-rated drywall at $7 per SF when everyone else is at $5.10.

Step 4: Ask for Assumptions

Request that each contractor list their assumptions in writing. "Assumes drywall is delivered to the jobsite." "Assumes demo contractor removes existing framing." "Assumes electrical will coordinate all cuts in framing."

This one document prevents 90% of scope disputes later.

Evaluating and Comparing Bids

Don't Just Pick the Lowest Number

You already know this, but: the contractor who bid $28K on drywall while everyone else is at $32K probably missed something. Call them. Ask what they excluded. If they say "nothing," ask them to walk you through the fire-rated drywall footage and cost-per-square-foot again.

A contractor who comes in significantly low is either desperate, disorganized, or doesn't understand the scope. None of those end well for you.

Use a Scope Gap Checker

Create a system (or use a tool like our scope gap checker) to flag when one contractor's bid is missing items that other contractors included. Drywall Contractor A includes fire-caulk; Contractor B doesn't. That's a $2K-$4K difference right there.

Do this before you sign a contract, not after.

Consider the Relationship, Not Just the Price

If you've worked with a framing crew on five previous TI jobs and they execute cleanly, showing up on time and leaving the jobsite in good shape, a $1,200 price difference might be worth paying. They'll also catch coordination issues because they know how you operate.

New contractors who are hungry for work need scrutiny. They'll lowball and make it back on RFIs and change orders.

Red Flags in Commercial TI Bids

Vague Line Items

"General labor—$4,500." What labor? Framing assistance? Cleanup? Coordination? This tells you the contractor didn't price the job carefully.

Bids That Don't Match Your Scope

You requested drywall, electrical, plumbing, and HVAC bids separately. One contractor submitted a combined estimate. They're either confused or they're assuming you'll hire them for all trades. Either way, they don't understand your project structure.

No Detailed Assumptions

If a contractor submits a bid with zero written assumptions, they're cutting corners on estimating. They'll be cutting corners in the field too.

Typos and Math Errors

Small errors might just mean they're sloppy. But they might also mean they bid it in a hurry and didn't QC their own work. Do you want someone sloppy managing your mechanical work?

Negotiating Without Killing the Relationship

Go Back to the Scope, Not the Price

Never ask a contractor "Can you do this for $30,000 instead of $35,000?" They'll say yes, cut scope, and blame you when they run short on materials.

Instead: "I've got another bid that includes fire-caulk at the demising wall and exterior sealant at the window heads. Can you clarify what's in your scope for those items?"

If they forgot those items, they'll add cost. If they included them, they'll show you. Either way, you're comparing true apples-to-apples now.

Use Competitive Bids as Information, Not Weapons

"I've got a bid at $32,000 for drywall, and you're at $38,000. What's the difference?" gives the contractor a chance to clarify. Maybe they included premium finishing because they quoted a higher-end paint spec. Maybe they miscalculated. But you're having a conversation, not just negotiating a number.

Build in Contingency Properly

Don't ask contractors to bid with a 10% cushion built in. Bid the work as scoped, then carry contingency at the GC level. This way you're making a real decision about who's cheapest and best, not just guessing which bid inflated their number most.

After You've Selected Your Subs

Get a Signed Proposal That Matches Your Bid Package

The contractor's proposal should reference your scope document by date and revision number. "See Scope Document dated 2/15/2024 provided to contractor on 2/16/2024." Not vague references to "the plans."

Include Schedule Requirements

A drywall contractor needs to know when they're mobilizing and when they need to be done. If they mobilize two weeks late, your HVAC and plumbing contractors are sitting idle. Make this explicit in the contract.

Walk the Space Together Before Work Starts

You've sent a detailed scope and a signed contract. The contractor thinks they understand. Walk the space with them anyway. Show them the demising wall, point out the mechanical chases, indicate where existing walls are coming down.

This conversation—in person, in the space—eliminates most RFI disputes before the work starts.

Tools to Keep Commercial TI Bidding Organized

If you're managing multiple TI projects with 15-20 subcontractor bids per job, tracking everything in email and spreadsheets is going to fail. You'll miss a bid, miss a scope gap, or miss a deadline.

Consider a bid management system that lets you organize bids by trade, flag scope gaps automatically, and generate reports that compare contractors side-by-side. Something like ClearBids is built for exactly this—contractors submit bids, the system flags when one bid is missing line items that others included, and you get a summary report in minutes instead of hours.

For commercial TI specifically, you want a tool that understands construction scope and can flag not just price outliers but scope outliers too.

Final Thoughts: Bidding Is Where You Make or Lose Money

The actual construction work is where you deliver. But the bidding process is where you win or lose money. A thorough scope document, detailed line-item bids, clear assumptions, and a system to compare them—this is how you build profitable TI projects.

You can't control the market. You can't control material costs. But you can control whether you understand exactly what your subcontractors are pricing and why one bid is different from another.

That control is worth hours of effort in the bidding phase.