Does Terrapin Construction Group work as a subcontractor to other general contractors?

Yes. Terrapin Construction Group provides IMP supply and installation as a specialty subcontractor to general contractors nationwide and turnkey design-build to owners. TCG self-performs with in-house crews and has installed over 1 million square feet across 38 states. Licensed in all 50 states.

IMP Subcontractor for General Contractors: Scope, Cost, and Schedule (2026)

Q: What should be included in an IMP subcontractor's scope?

Panel supply, installation, all joint detailing and sealant, inside and outside corner trim, base trim, parapet closure, penetration flashing, fasteners, and a manufacturer warranty tied to the installation warranty.

Q: How far in advance should I engage an IMP subcontractor?

At the 50 percent design development stage. Panel module, joint orientation, base detail, and roof interface are cheaper to resolve on paper than in the field.

Aug 14

Written By William Goodin

IMP Install / For General Contractors

IMP Subcontractor for General Contractors

You have a cold storage, food processing, or data center project with an insulated metal panel scope, and you do not self-perform panel. This is what the work actually costs in 2026, how fast real crews install, the five places IMP bids go wrong, and the questions that separate an installer from a broker.

Terrapin Construction Group · Updated July 2026

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The Short Answer

What IMP Costs a GC in 2026

Insulated metal panel supply and installation runs $12 to $35 per square foot in 2026, depending on core thickness, manufacturer, profile, and finish. A qualified crew installs 800 to 1,500 SF per day. Most general contractors subcontract the scope and absorb 8 to 20 percent in markup plus a coordination layer that quietly consumes schedule float.

The number that matters to you is not the per-SF price. It is whether the bid includes the joint detailing, flashing, trim, sealant, and fastener package. That is where IMP bids diverge, and it is why the low bid is frequently the most expensive one.

2026 Installed IMP Pricing by Application

Panel price is a function of core thickness and core chemistry before it is a function of anything else. Polyiso, mineral wool, and EPS carry different R-values per inch, different fire ratings, and materially different costs. These are supply-and-install numbers, not material-only.

Application	Panel Spec	Installed
Architectural wall	2 to 3 inch, exposed fastener or concealed	$12–$25
Cooler wall	4 inch, approx. R-32	$14–$24
Ceiling panel	Suspended, load-rated	$14–$28
Freezer wall	5 to 6 inch, R-40 to R-48	$18–$30
Cleanroom / pharma	Flush, cleanable, gasketed	$22–$35
Blast freezer	6 inch+, high-performance joint	$24–$35

A cold storage envelope bid under $14 per square foot installed is not a better price. It is a smaller scope.

If you are carrying a number below that floor, go find the exclusions page. In almost every case the gap is trim, flashing, sealant, or the fastener package, and it lands back on your general conditions when the panel subcontractor demobilizes. For the full envelope picture on refrigerated projects, see cold storage construction cost and IMP versus tilt-up for cold storage.

Crew Productivity and What It Does to Your Schedule

A trained IMP crew installs 800 to 1,500 square feet per day. That range is wide because panel length, crane availability, wall height, and the number of penetrations move it more than crew size does. Run the math before you commit a date to the owner.

On a 60,000 SF freezer envelope, one crew at 1,000 SF per day is roughly 60 working days, or about twelve weeks. Two crews is six. If your schedule assumed four, you did not have an installation problem. You had an estimating problem. Panel lead times compound it: see 2026 material lead times.

The Markup Question

Most GCs subcontract IMP and add 8 to 20 percent. That is a legitimate charge for risk and coordination. The problem is that a broker in the middle adds the same markup without adding crews. If your panel subcontractor does not employ the installers, you are paying a coordination fee to someone who also has to coordinate. Ask who is on the payroll.

The Five Places IMP Bids Go Wrong

Joint detailing is excluded or assumed. The panel joint is the entire thermal and vapor performance of the envelope. If the bid does not name the joint detail, the sealant product, and who installs it, the scope is undefined. See the IMP joint detailing and waterproofing guide.
Trim and flashing land nowhere. Inside and outside corners, base trim, parapet closure, and penetration flashing are frequently split between the panel bid and the roofing bid, which means neither carries them. This is the single most common change order on a panel scope.
FM approval is assumed rather than specified. If the insurer requires an FM 4880 or FM 4881 assembly, the panel, the fastener, and the joint all have to be part of the approved assembly. Substituting one component voids it. See why FM ratings matter and polyiso versus EPS by rating.
Structural tolerance is not verified. Panel is unforgiving of out-of-plumb steel. If the PEMB or structural steel is outside tolerance, the panel crew stops. Confirm who is responsible for survey and remediation before the first panel arrives.
Sequencing against roofing and refrigeration is unresolved. Wall panel, roof, and the refrigeration contractor all want the same space at the same time. See the day-by-day install sequence for cold storage.

Seven Questions to Qualify an IMP Bidder

IMP has a low barrier to bidding and a high barrier to performing. These questions separate the two faster than a reference check, and you can ask all of them in one phone call.

Do you employ the installers, or do you broker the crews? Payroll versus purchase order is the difference between a schedule commitment and a hope.
How many square feet have you installed, and in how many states? Volume across jurisdictions is the proxy for having seen the failure modes.
Which manufacturers are you approved with? Direct relationships affect both lead time and warranty. TCG works with PermaTherm, Kingspan, Metl-Span, CENTRIA, AWIP, MBCI, FALK, UPI Panels, and Arch Solar. Compare them in the manufacturer guide.
Is the manufacturer warranty single-source with the installation warranty? Split warranties are where envelope claims go to die.
What is your daily production rate, and how many crews can you field? Get the number in writing and check it against your schedule before award.
Show me the exclusions page first. Read exclusions before price. Our guide to reading a bid applies directly here.
Who is the foreman on my job, and what have they installed? IMP quality is a crew attribute, not a company attribute.

When to Bring the Panel Sub In

Earlier than you think. The decisions that determine whether a panel scope goes smoothly are made in design development, not at bid: panel module versus column spacing, joint orientation, base detail at the slab, and how the envelope meets the roof. A panel subcontractor brought in at the 50 percent drawing stage will typically find $50,000 to $150,000 of avoidable cost on a mid-size cold storage envelope, mostly in trim simplification and module rationalization.

Brought in at bid, that same subcontractor prices what is drawn and carries contingency for what is not. You pay for the ambiguity either way. The only question is whether you pay for it as a bid contingency or as a change order.

What TCG Does for General Contractors

We self-perform IMP installation with in-house crews on payroll. Over 1 million square feet installed across 38 states in the last ten years, on cold storage, food processing, cannabis, pharmaceutical, cleanroom, and data center projects. Licensed in all 50 states, Procore certified, with regional offices in Denver, Houston, Albany, and Sheridan.

We work as a specialty subcontractor to general contractors and as a turnkey design-build partner to owners. When you hire us as a sub, you are hiring the crews, not a coordination layer. See IMP installation services or price a scope with the free IMP install estimator.

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Send us the elevations and the wall sections. We will come back with supply-and-install pricing, a production rate, and a written exclusions page you can compare line for line against your other bids.

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IMP Subcontractor FAQ

How much does IMP installation cost per square foot in 2026?

Supply and installation runs $12 to $35 per square foot in 2026. Architectural wall panels run $12 to $25/SF. Cooler walls at 4 inch and R-32 run $14 to $24/SF. Ceiling panels run $14 to $28/SF. Freezer walls at 5 to 6 inch and R-40 to R-48 run $18 to $30/SF. Cleanroom and pharmaceutical panels run $22 to $35/SF. Blast freezer runs $24 to $35/SF. Pricing below $14/SF installed on a refrigerated envelope usually signals excluded trim, flashing, or joint sealant.

How fast can an IMP crew install panel?

A trained crew installs 800 to 1,500 square feet per day. Panel length, wall height, crane availability, and penetration count drive that range more than crew size does. On a 60,000 SF envelope, one crew at 1,000 SF per day is roughly twelve working weeks.

Should a general contractor self-perform IMP or subcontract it?

Subcontract it unless you have crews with panel-specific experience. IMP is unforgiving of installation error, and the failure modes, thermal bridging, condensation, and joint leakage, appear months after substantial completion when the facility is operating. Most GCs subcontract and add 8 to 20 percent markup for coordination and risk.

What should be included in an IMP subcontractor's scope?

At minimum: panel supply, installation, all joint detailing and sealant, inside and outside corner trim, base trim, parapet closure, penetration flashing, fasteners, and the manufacturer warranty tied to the installation warranty. If any of those sit outside the bid, identify who carries them before award.

What is FM 4880 and FM 4881, and why does it affect my bid?

They are FM Approvals standards for interior wall assemblies and exterior wall systems. Insurers frequently require them on cold storage and food processing facilities. The approval covers the full assembly, panel, fastener, and joint together, so substituting one component to save cost can void the approval and the insurance position.

How far in advance should I engage an IMP subcontractor?

At the 50 percent design development stage if you can. Panel module, joint orientation, base detail, and roof interface are all cheaper to resolve on paper. Engaging at bid means you pay for the ambiguity as contingency or as change orders.

Does TCG work as a subcontractor to other general contractors?

Yes. Terrapin Construction Group provides IMP supply and installation as a specialty subcontractor to general contractors nationwide, and separately provides turnkey design-build to owners. We self-perform with in-house crews and have installed over 1 million square feet across 38 states. Licensed in all 50 states. Schedule a 30 minute call or use the free IMP estimator.