R-30 Insulation Rolls
Wholesale fiberglass R-30 in 9.5" thickness. The standard ceiling spec in mixed and cold climates — and the IECC ceiling minimum for Climate Zones 4, 5, and 6.
What Is R-30 Insulation?
R-30 insulation is fiberglass batt or roll insulation rated at R-30 thermal resistance under ASTM C518. The 30 represents resistance to heat transfer — 50 percent higher than R-19 and 20 percent higher than R-25. R-30 is the highest standard-line R-value in the Insulation Overstock catalog.
R-30 is primarily a ceiling and attic insulation. The 9.5-inch nominal thickness fits 2x10 framing, which is uncommon in wall construction but standard in ceiling joists and rafters. It is the IECC ceiling minimum for Climate Zones 4, 5, and 6 — covering most of the continental United States — and the recommended ceiling spec for any climate where heating or cooling costs are a concern.
At Insulation Overstock, R-30 is available in VR-R Plus and WMP-50 facings (the two product lines extending into the R-30 thickness range). Wholesale pricing runs $1.36 to $1.42 per square foot. For ceiling and attic applications where the full thickness fits, R-30 represents the best long-term thermal value in fiberglass insulation.
R-30 Insulation Thickness and Composition
R-30 Nominal Thickness
R-30 fiberglass insulation has a nominal installed thickness of 9.5 inches. The full thickness is required to deliver rated R-30 performance. Compression to a shallower cavity loses performance proportionally: R-30 compressed to 8 inches delivers approximately R-25; compressed to 6.25 inches it delivers approximately R-19.
R-30 Roll Dimensions
R-30 rolls ship in standard 4-foot, 5-foot, and 6-foot widths. Roll lengths are shorter than thinner R-values (typically 16 to 32 feet) because of the thicker material profile.
Facing Options for R-30 Rolls
R-30 is available with two facing lines: VR-R Plus (PSP) and WMP-50 (PSKP). The narrower facing selection at R-30 reflects manufacturing dimensional constraints — not all facings extend into the 9.5-inch thickness range. For most ceiling applications, the limited facing selection is not a constraint because facing visibility is rarely the priority in ceiling installations.
Where R-30 Insulation Works Best
R-30 Insulation by IECC Climate Zone
R-30 is the IECC ceiling minimum for Climate Zones 4, 5, and 6 and is the recommended ceiling spec for any climate where energy costs are a meaningful budget line.
| IECC Zone | Example States | R-30 Used For |
|---|---|---|
| Zone 1-2 | FL, southern TX | Ceilings (minimum) |
| Zone 3 | TX, GA, NC, AZ | Ceilings (minimum) |
| Zone 4 | VA, TN, KY, MO | Ceilings (minimum) |
| Zone 5 | CO, OH, IL, NY | Ceilings, attics |
| Zone 6 | MN, WI, MT, ME | Ceilings, attics |
| Zone 7 | Northern MN, WI, ME | Walls (in 2x10), ceilings (R-38+ preferred) |
| Zone 8 | Northern AK | Walls, ceilings (R-49 preferred) |
For a complete R-value breakdown across all climate zones, see the R-Value Guide by Climate Zone.
R-30 Insulation Cost Per Square Foot
Wholesale R-30 fiberglass insulation pricing at Insulation Overstock runs $1.36 to $1.42 per square foot. R-30 carries the most material per square foot of any standard R-value (9.5 inches of fiberglass) and the price reflects that.
- VR-R Plus (vinyl-reinforced PSP): $1.36 / sq ft
- WMP-50 (PSKP metalized premium): $1.42 / sq ft
The Insulation Calculator returns total R-30 cost (material + freight + service fee) for any square footage and state. For larger orders, Bulk Insulation includes the $250 volume discount.
Available Facings for R-30 Rolls
Two facings extend into the R-30 thickness range. Both are appropriate for ceiling and attic applications.
VR-R Plus (PSP) — Most Economical
VR-R Plus at $1.36 per square foot is the value choice for R-30 ceilings. Vapor retardant facing suitable for most U.S. climates.
WMP-50 (PSKP) — Premium Metalized
WMP-50 at $1.42 per square foot is the premium choice. The metalized polyester backing adds a radiant barrier in addition to the R-30 thermal performance — useful in metal-roof applications where reducing radiant heat gain matters.
R-30 vs Other R-Values
| R-Value | Thickness | Best For | Wholesale Price/Sq Ft |
|---|---|---|---|
| R-13 | 3.625" | 2x4 walls | $0.65 – $0.75 |
| R-19 | 6.25" | 2x6 walls, Zone 3-4 | $0.90 – $1.00 |
| R-25 | 8.0" | Zone 5+ walls, ceilings | $1.13 – $1.23 |
| R-30 | 9.5" | Ceilings, attics, 2x10 framing | $1.36 – $1.42 |
Choose R-30 when: insulating a ceiling, attic, or 2x10 framed assembly in any climate where year-round HVAC operates — the upgrade typically pays back in 5-8 years on a heated/cooled building.
Stay with R-25 when: framing is 2x8 walls or you need the dimensional fit. R-25 is also the right pick for cold-climate walls where R-30 would require 2x10 framing not originally planned.
Consider R-38+ when: building in Climate Zone 7 or 8, or for cathedral ceilings where the framing depth allows for higher R-values.
R-30 Insulation FAQ
What is R-30 insulation?
R-30 insulation is fiberglass batt or roll insulation rated at R-30 thermal resistance per ASTM C518. It is the standard ceiling and attic insulation spec in mixed and cold climates and the IECC ceiling minimum for Climate Zones 4 through 6.
How thick is R-30 fiberglass insulation?
R-30 fiberglass insulation is 9.5 inches thick at nominal installed depth. The full thickness is required for rated performance.
How much does R-30 insulation cost per square foot?
Wholesale R-30 fiberglass insulation runs $1.36 to $1.42 per square foot at Insulation Overstock. VR-R Plus is $1.36; WMP-50 (metalized premium) is $1.42.
Is R-30 worth it over R-25?
For ceilings and attics, yes — R-30 delivers about 20 percent better thermal performance than R-25 at about 20 percent higher cost. The upgrade typically pays back through reduced heating and cooling costs within 5 to 8 years in a year-round conditioned building.
Can I install R-30 in a 2x8 wall?
No — R-30 requires 9.5 inches of cavity depth, and 2x8 framing provides only 7.25 inches. Compressing R-30 into a 2x8 reduces it to roughly R-25. For 2x8 framing, order R-25. For 2x10 framing (ceilings and floors), R-30 is dimensionally correct.
Where is R-30 required by code?
R-30 is the IECC ceiling minimum for Climate Zones 4, 5, and 6 — roughly the mid-Atlantic, Midwest, and northern mountain states. In Zones 7 and 8, R-38 or higher is required. In Zones 1, 2, and 3, R-30 ceilings are not strictly required but are commonly used for energy efficiency.
Order R-30 Fiberglass Insulation
Wholesale R-30 for ceiling and attic applications. Material, freight, and service fee itemized separately.
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