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Metal Building Insulation Systems for Contractors and Builders

Metal buildings punish bad insulation. Condensation drips off the roof. Thermal bridging at every girt and purlin eats your R-value. Energy code asks for more than a single layer of blanket can give.

 

IDI supplies the wall and roof systems that fix those problems, for new construction and retrofit. Fiberglass, fabric liner, rigid board, reflective and spray foam. We stock it at more than 65 locations, and we back it with take-offs, cut sheets and technical support before the order ships.

Or give us a call at 888.843.7230

Why Metal Buildings Are Hard To Insulate

Steel moves heat fast, and every framing member is a path for it. Insulating a metal building means managing five problems at once.

Temperature. Steel conducts. Without a real insulation system, the envelope swings with the weather and the HVAC fights it all year.

Condensation. Warm interior air hits cold steel and turns to water. Facing perm rating matters, and so does filling the cavity so there is no dead space for moisture to form. Trapped moisture erodes building materials over time.

Thermal bridging. Girts and purlins cut through the insulation layer. Every one of them drops the effective R-value of what you installed.

Sound. Insulation keeps machinery noise inside and improves acoustics. That matters in shops, plants and any building with loud equipment.

Code. Energy codes have moved. A single layer roof system does not meet the requirements for conditioned space in most of the US. Confirm the requirement for your climate zone and code year before you spec.

The right system depends on the roof type, the framing, the code and how the building will be used. That is why system choice matters more than it used to.

Metal Building Insulation Products IDI Stocks

IDI supplies the full set of metal building insulation products, from standard blanket to high-R liner systems, plus the accessories to finish the install. Here is what is on the shelf, and what is not.

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Metal Building Wall Insulation Systems

Pick the wall system before the panels go up, because some systems go on the outside of the girts, some go inside, and several need coordination with the building manufacturer. Here is how the common steel building wall systems compare.

01

Standard Blanket

Faced fiberglass between the outside face of the girts and the exterior wall panel · R-7 to R-19

Best for

Low install cost, easy retrofit, approved air barrier

Watch out for

Thermal bridging at each girt cuts the effective R-value

02

Filled (Girt) Cavity

Fills the girt cavity · thermal break tape goes on the outside face of the girts before the panels

Best for

Low cost, easy install, stops air leaks and critters

Watch out for

Can interrupt the purlins

03

Fabric Liner

Panels first · unfaced fiberglass goes between the girts on hangers, then the liner goes over everything

Best for

New and retrofit, meets most energy codes, high-quality vapor and air barrier, clean white finish

Watch out for

Complex install. Harder to reach purlins for electrical, maintenance and HVAC. Needs coordination with the building manufacturer

04

Rigid Board (Polyiso)

Continuous layer over the framing

Best for

Continuous insulation, less thermal bridging, durable facings, meets most codes

Watch out for

Cost, special lengths, joints, trim and building lines. Exposed board, or board behind a liner thinner than 22 gage, needs a Class A fire rating

05

Standard Faced Fiberglass

Faced insulation equal to or slightly deeper than the girts, installed after the wall panels

Best for

Low-cost way to meet higher energy codes, panels go up fast

Watch out for

Insulation width has to match girt spacing. Needs coordination with the building manufacturer

06

Spray Foam

Applied directly to the inside of the wall panels

Best for

Smaller buildings. Closed cell adds rigidity

Watch out for

May void building manufacturer warranties. Costs more than fiberglass. See the spray foam section below

07

Insulated Metal Panels

The panel is the insulation

Best for

Continuous insulation, clean finish inside and out

Watch out for

Cost, special install equipment. IDI does not sell these

 

Not sure which fits?

Send us the building details and a specialist will help you pick the wall system.

Send us the details

Three rules for every wall job.

 

1. Fill the cavity. Match the insulation depth to the girt depth, or go slightly deeper. Empty space is where condensation forms.
2. Know who else signs off. Liner, standard faced and rigid board systems all need coordination between the insulation supplier and the building manufacturer. Settle it before the order, not after the crew is on site.
3. Fiberglass is still the workhorse. It gives you the lowest installed cost per R-value, in a range of facings. Your crew needs proper PPE to install it.

 

Not sure which wall system fits the building? Send us the details and we will help you sort it out.

Metal Roof Insulation Systems

The roof is where code and condensation collide, so match the metal building roof insulation system to the roof type, the R-value you need and the framing. Get it wrong and condensation and water damage start eating the building.

01

Single Layer Faced Blanket

R-10, R-13, R-16, R-19 · R-13 max with screw-down roofs

Over and perpendicular to the purlins, facing in · roof panels go straight over it

Best for

Low cost, easy install, traditional look

Watch out for

Will not meet most energy codes for conditioned space. Thermal bridging costs R-value

02

Sag and Bag, Two Layer

High R at low cost on paper

Faced layer over the purlins with enough sag, then unfaced between the purlins

Best for

Low cost, easy install

Watch out for

Inconsistent sag and thermal bridging at the purlins. Does not meet most energy codes for conditioned space

03

Long Tab and Banded, Two Layer

R-30 to R-38

Faced layer between the purlins over banding about 30 inches on center, then unfaced layer across the top

Best for

High R at low cost, various facings, installs from the roof deck, other trades keep access to the bottom purlin flange

Watch out for

Purlin channel bracing and sag angle bracing are hard to work around. Needs coordination with the building manufacturer

04

Spray Foam

Varies

Applied from the inside · closed cell is typical

Best for

Screw-down roofs

Watch out for

Not recommended on standing seam roofs. See the spray foam section below

05

Rigid Board

Continuous insulation

Over the purlins, roof panel installed directly on the board

Best for

Easy install, less thermal bridging

Watch out for

Higher cost and joint conditions. Exposed board needs a Class A fire rating

06

Fabric Liner, Multilayer

Meets or exceeds building energy codes

Liner below the purlins on banding, unfaced layer between the purlins over the liner, second unfaced layer across the top

Best for

Air and vapor barrier, clean finish, fills the purlin cavity, works in retrofit and with bracing, most liners give leading-edge fall protection

Watch out for

Harder to install the first time. Needs coordination with the building manufacturer

07

Reflective

Not a stand-alone R-value fix

Radiant barrier of high-grade aluminum

Best for

Solar heat gain, or buildings with lots of windows and skylights

Watch out for

Match it to the problem. It does not replace insulation where heat loss is the issue

08

Insulated Metal Panels

Consistent R-value

The panel is the insulation

Best for

Clean interior finish

Watch out for

Cost, special equipment, load and trim coordination. IDI does not sell these

Quick picks

1. Unconditioned space, screw-down roof: single layer, up to R-13.
2. Need R-30 to R-38 and want to install from the deck: long tab and banded.
3. Need code compliance, an air and vapor barrier, or leading-edge fall protection: fabric liner multilayer.
4. Need continuous insulation and less thermal bridging: rigid board.
5. Solar heat gain is the problem: reflective.

 

Rigid board on a standing seam roof? Make sure end laps land on a purlin connection, tape the outside joints, and ask the building manufacturer whether bearing plates are needed for the roof clip attachment. Send us the details and we will help you sort it out.

Spray Foam Insulation for Metal Buildings

Spray foam works on some metal buildings and can void the warranty on others, so check before you quote it. Over the past several years it has become an effective option for metal building walls, mostly on smaller buildings.

 

Walls: Foam goes directly on the inside of the metal panels. Prep the panel and make sure the surface is ready to accept it. Closed cell is typical, and it adds rigidity to the building. Open cell works in some applications. If the foam is left exposed, it needs a fire-rated coating.

Roofs: Spray foam can go under a screw-down roof system. We do not recommend it under standing seam. Closed cell is rigid, and standing seam roofs are designed to expand and contract.

Warranties: Spray foam may void the building manufacturer's warranty. Ask the building supplier before you spec it, and get the answer in writing.

 

IDI supplies spray foam, rigs and training. We do not install it, but we work with thousands of insulation contractors who do. Getting into metal building work?

Warehouses, Pole Barns, Retrofits And Other Problem Jobs

Most metal building jobs fall into one of six situations, and each one changes the system you pick.

01

New Construction
You have the most options, and the earliest decision is the most important one. Pick the wall and roof systems while the building package is still being specified, so the insulation and the building manufacturer are working from the same drawings.

02

Retrofit
Standard blanket and fabric liner systems both work on existing buildings. Liner also gives you a finished white interior and an air and vapor barrier. Long tab and banded roof systems install from the roof deck. Retrofit metal building insulation starts with what is already up there, so send us photos and framing details.

03

Warehouse And Industrial
Big roofs and tall ceilings make the roof system the deciding factor. A single layer will not meet code for conditioned warehouse space in most of the US, so look at long tab and banded, fabric liner or rigid board. Warehouse ceiling insulation also controls sound from loud equipment.

04

Pole Barns And Post-Frame
Pole barn insulation deals with the same metal panel condensation problem as any steel building. Many pole barns are wood framed, so confirm the wall and roof framing before you pick a system. The options come from the same toolbox: faced fiberglass, fabric liner, rigid board or spray foam.

05

Agricultural And Storage
Wide-open spans, metal construction, condensation risk and unconditioned or semi-conditioned space all show up here. Fill the cavity, use the right facing, and plan for moisture first. See our agriculture insulation information for more.

06

Energy-code Upgrades
Older buildings often have a single layer roof that cannot meet current code. Upgrading to a fabric liner multilayer system or a long tab and banded system is the usual path to compliance. Confirm the code year and climate zone with the building department before you spec.

How to Insulate A Metal Building

Most metal building jobs that go sideways went wrong before the crew showed up. Work through these steps on every job, and use IDI when you want a second set of eyes.

1. Get the building details

Find out the roof type (standing seam or screw-down), the wall and roof framing, whether it's new or a retrofit, whether the space will be conditioned, and who the building manufacturer is. Plans are best. On a retrofit, take photos of the framing and whatever insulation is already up there.

2. Confirm the code requirement

Check the energy code year and climate zone with the building department, and pin down the wall and roof R-values before you pick a system. A single layer roof won't meet code for conditioned space in most of the US.

3. Pick the wall and roof systems

Match each system to the roof type, framing, R-value and how the building will be used. The charts above lay out the options. If you're stuck between two, our specialists can talk it through with you.

4. Coordinate with the building manufacturer

Liner, long tab and banded, standard faced and rigid board systems all need their sign-off. Spray foam may void their warranty. Settle it and get the answer in writing before you order, not after the crew is on site.

5. Build the material list

Include the insulation, the facing and every accessory: hangers, thermal break tape, banding, tape and fasteners. IDI can help with take-offs and cut sheets if you want them.

6. Order and stage the materials

More than 65 IDI locations stock metal building insulation and accessories. Check the accessories against the order so your crew isn't waiting on a missing box of tape.

7. Install it right

Fill the cavity, seal the facing seams and keep the crew in proper PPE. If the install hits a snag, call your IDI rep.

Metal Building Insulation FAQ

Does a single layer blanket meet energy code on a metal roof?

In most of the US, not for conditioned space. Single layer systems run R-10 to R-19, and only up to R-13 is recommended with a screw-down roof. For conditioned space, look at long tab and banded, or a fabric liner multilayer system.

What is the best insulation for a metal building roof?

It depends on code, roof type and whether the space is conditioned. Fabric liner multilayer systems are popular because they meet or exceed energy code, act as an air and vapor barrier and reduce thermal bridging. Long tab and banded systems reach R-30 to R-38 at a lower cost.

What is the cheapest way to insulate a metal building?

Fiberglass gives you the lowest installed cost per R-value. The cheapest systems on paper, single layer and sag and bag, often will not meet code for conditioned space. Check the code first, then price the systems that pass.

How much does it cost to insulate a metal building?

It depends on the system, the R-value, the facing and the size of the building. A take-off gives you real numbers. Send us your plans and we will build one.

How do you stop condensation in a metal building?

Fill the cavity so there is no dead space, and choose a facing with the right perm rating. Add an air and vapor barrier with a facing or liner system. Cut thermal bridging with liner systems or thermal break tape on the girts.

Can you use spray foam on a standing seam roof?

We do not recommend it. Closed cell foam is rigid, and standing seam roofs are designed to expand and contract. Spray foam can work under a screw-down roof. Check the building manufacturer's warranty first.

Can you retrofit insulation into an existing metal building?

Yes. Standard blanket and fabric liner systems both work in retrofit. Long tab and banded roof systems install from the roof deck.

How do you insulate a pole barn?

Start with the framing and the condensation risk, then pick the system. Faced fiberglass, fabric liner, rigid board and spray foam are all on the table. Ask a specialist about your build.

Does IDI install insulation?

No. IDI supplies materials, equipment, training and technical support to the contractors who install.

Grow Your Capabilities With IDI

IDI is more than an insulation distributor, we want to be your insulation partner that helps your business succeed. That’s why we offer some of the industry’s best trainings, led by recognized experts who cover a wide range of topics including: product advancements, equipment and application demonstrations, marketing, building science, safety best practices, and more. Not only will you learn how to create better metal building insulation systems, you and your team will learn how to increase efficiency, boost your bottom line, and improve your technique. 

 

IDI hosts training sessions across the country, so be sure to check out our upcoming schedule to find one near you!

Tell Us About Your Metal Building Project

Every metal building insulation project is different. Whether your team is dealing with new construction, a retrofit for an existing structure, or evaluating systems to meet modern energy codes, we want to hear about what you’re working on. IDI can help you identify the correct products for your project, while providing the expert support you need to keep jobs moving forward efficiently.