Roof & Wall Systems
Everyday R-10 to R-19 blankets, or multi-layer systems when you need more R-value.
Why Insulate a PEB
Fiberglass metal building insulation is laminated or unfaced, sized for purlin and girt spacing, and finished with a vapor retarder facing that becomes the interior surface.
We help you choose between the most common single-layer packages — 3″ (R-10), 4″ (R-13), and 6″ (R-19) with white reinforced facing — and higher R-value multi-layer systems (often R-25 to R-38+ installed R) that place unfaced insulation over the purlins/girts and fill the cavity between them.
Most Common System
The workhorse package for pre-engineered metal buildings — laminated fiberglass in standard thicknesses with a white reinforced vapor-retarder facing.
Nominal laminated R-value · ~3⅜″ recovery
Common for unconditioned or lightly conditioned shops and storage where condensation control and a finished look matter more than maximum R-value.
NAIMA 202-class metal building insulation · confirm after-lamination R on quote
Nominal laminated R-value · ~4⅜″ recovery
A popular middle thickness for shops, warehouses, and farm buildings — solid thermal performance without a multi-layer system.
Also available: R-11 (~3¾″) and R-16 (~5¼″) single-layer options
Nominal laminated R-value · ~6⅜″ recovery
Often chosen when you want more thermal resistance in a single laminated blanket — still the common install method, thicker blanket.
Thicker single-layer options include R-25 (~8″) and R-30 (~9¼″) where specified
| Nominal R-value | Typical recovery thickness | Common PEB use |
|---|---|---|
| R-10 | ~3⅜″ (marketed as 3″) | Shops, storage, light commercial — most common thin package |
| R-11 | ~3¾″ | Alternate thin package; also used as cavity-fill layer in high-R systems |
| R-13 | ~4⅜″ (marketed as 4″) | Balanced everyday roof/wall package |
| R-16 | ~5¼″ | Step-up single-layer when R-13 is not enough |
| R-19 | ~6⅜″ (marketed as 6″) | Most common thicker single-layer; frequent high-R outer layer |
| R-25 | ~8″ | Heavy single-layer or multi-layer high-R combinations |
| R-30 | ~9¼″ | Maximum single-layer blankets; high-R system layers |
Nominal R-values are for NAIMA 202-class fiberglass metal building insulation after proper recovery. Compression over purlins/girts reduces installed performance — multi-layer systems improve continuity over steel.
The most common facing is a white, reinforced vapor-retarder facing known as PSK-VR (poly-scrim-kraft style vapor retarder). The scrim reinforcement helps resist tearing during handling and erection. Facing is installed toward the building interior for a bright, clean finished look.
For high-abuse interiors — gyms, arenas, livestock areas, or busy industrial spaces — heavier, puncture-resistant facings are available. These “Gymguard-class” products provide a tougher vapor-retarder surface while keeping the same single-layer install approach.
Laminated single-layer insulation is typically run over and perpendicular to the structural members (purlins on the roof, girts on the walls), with the facing toward the interior. It can also be placed between members depending on the system and drawings. Tabs and tape seal facing seams for a continuous vapor retarder. Always follow project drawings, manufacturer instructions, and local energy code requirements.
Higher R-Value System
When energy codes, conditioned space, or long-term operating cost demand more than single-layer R-10–R-19 — typically stacking layers into the R-25 to R-38+ installed range.
Layer 1
Unfaced fiberglass is installed over and across the structural members — commonly R-19, R-25, or R-30 — creating continuous coverage that reduces thermal bridging through steel flanges.
Layer 2
A second layer fills the cavity between members — often R-11, R-13, or R-19 — the “filled cavity” approach that stacks R-value where the structure has depth.
Finish
A vapor-retarder fabric or laminated layer finishes the interior. Support banding holds the system, often keeping purlins accessible for trades.
Entry high-R
R-19 + R-11
R-19 unfaced over purlins + R-11 cavity fill — solid step up from single-layer R-19.
Common high-R
R-25 + R-11
R-25 over members + R-11 between — frequent package for conditioned shops and commercial roofs.
Maximum high-R
R-30 + R-19
R-30 over + R-19 fill — for strict energy targets and fully conditioned industrial space.
Layer R-values are product nominal values. Installed assembly U-factors depend on purlin/girt spacing, compression, thermal blocks, and clips — we match the system to your drawings and energy-code path on quote.
Two (or more) layers — e.g. R-25 over + R-11 between — deliver more thermal resistance and better continuity over steel than a single R-19 blanket alone.
Unfaced insulation over purlins and girts covers steel flanges that would otherwise short-circuit a single cavity-only layer.
Many filled-cavity / long-tab style installs leave purlins accessible for electrical, HVAC, and sprinkler work after insulation.
Quick Compare
| Feature | Common: Single-layer faced | Higher R: Multi-layer |
|---|---|---|
| Typical use | Shops, barns, storage, light commercial | Conditioned / code-driven buildings |
| Layers | One laminated blanket — 3″ R-10 / 4″ R-13 / 6″ R-19 | Unfaced over (e.g. R-19–R-30) + fill between (e.g. R-11–R-19) |
| Facing | PSK-VR white (or Gymguard-class) | Liner fabric or laminated finish layer |
| Thermal performance | Typically R-10, R-13, or R-19 single layer | Often R-25–R-38+ combined layers / lower U-value |
| First cost | Lower | Higher material & labor |
| Best when | You need proven, economical PEB insulation | You need continuous high-R performance |
Listed R-values are nominal product values for NAIMA 202-class metal building insulation (e.g. R-10 ≈ 3⅜″, R-13 ≈ 4⅜″, R-19 ≈ 6⅜″). Installed assembly performance depends on compression at purlins/girts, thermal blocks, clips, and density. Final R / U selection is confirmed on your Stamps Steel quote and project drawings.
Tell us building type, roof vs. wall, and whether you need everyday single-layer or a higher-R system.
Get a QuoteShare thickness or system preference.