What Is California Title 24 and Why Does It Affect Your Roof?
Title 24 is California's Building Standards Code. Part 6 — the California Energy Code — sets minimum energy efficiency requirements for residential and commercial buildings. The California Energy Commission updates it every three years. The current version is the 2022 California Energy Code.
Title 24 matters to roofing because it applies at permitting. When you pull a building permit for a roof replacement, the permit application triggers an energy compliance review. In most Bay Area jurisdictions, that review includes attic insulation. If your attic insulation is below current code minimums, you may be required to bring it into compliance as a condition of permit approval.
This is not punitive — it is an opportunity. Reroofing is the lowest-cost time to upgrade attic insulation. The attic is accessible and the contractor is already on site. The extra labor cost of adding insulation during a re-roof is far lower than scheduling a separate project later.
Title 24 and the roofing permit — what to expect
Bay Area cities check energy compliance with different levels of scrutiny. Some require a CF1R form (the standard Title 24 energy compliance certificate) with the permit application. Others rely on a plan checker's review. Brian has pulled permits in Pleasanton, Livermore, Dublin, Fairfield, Vacaville, Stockton, and other Bay Area cities. He knows which ones are strict on insulation and which keep it simple. NuShake handles the Title 24 paperwork as part of any roofing permit.
Current R-Value Requirements — What the Code Actually Says
R-value measures how well insulation resists heat flow — higher is better. The 2022 California Energy Code sets a minimum, and that minimum changes by climate zone. The Bay Area spans several California Energy Commission (CEC) climate zones:
- Climate Zone 3 — coastal (San Francisco, Daly City, coastal Marin): R-38 minimum attic.
- Climate Zone 4 — coastal valleys (most of Contra Costa, Alameda, Solano): R-38 minimum attic.
- Climate Zone 12 — Sacramento Valley transition (including parts of Solano, Napa): R-38 minimum; R-49 for new high-performance construction.
- Climate Zone 13 — inland valley (Stockton, Ripon, Manteca): R-38 minimum; R-49 for high-performance.
In plain terms: R-38 is the floor for existing homes undergoing permitted work in the Bay Area. R-49 is the goal for maximum energy performance and may be required for some addition projects or new construction.
What R-38 means in physical terms
In real depth: R-38 of blown-in fiberglass is about 12 inches of insulation. R-49 is about 16 inches. Most older Bay Area homes have just 3–6 inches of original batts or compacted blown-in — R-11 to R-19 at best. The gap between what these homes have and what code now requires is large.
The 1950s–1970s Bay Area Home Problem
A large percentage of the Bay Area's housing stock was built between 1950 and 1975. These homes were built before California had meaningful energy code requirements. Attic insulation, if installed at all, was typically R-11 kraft-faced batts laid between floor joists — and those batts are now 50 years old.
Fifty-year-old fiberglass batts do not hold their original R-value. They compress and settle over time. They may have become damp from attic moisture cycles. In some cases, rodent activity has disrupted or contaminated the insulation. What started as R-11 may now be performing at R-6 or R-7.
The thermal consequence is direct. During a hot Tri-Valley summer, attic air temperatures can exceed 150°F. An R-7 attic floor is a poor barrier between 150°F and your living space. Your HVAC system compensates — and your PG&E bill reflects it. Upgrading from R-7 to R-38 in a Pleasanton or Livermore home can reduce cooling energy use by 20–30%.
Bay Area Climate Split — Coastal vs Inland Insulation Needs
The Bay Area has a pronounced climate gradient. Coastal and near-bay areas like San Francisco, Oakland, Richmond, and Fremont stay mild year-round. Summer highs rarely top 70°F and winter lows rarely drop below 40°F. In these zones, insulation matters mostly for moisture control and winter heating efficiency.
Inland East Bay and Tri-Valley zones cover Pleasanton, Livermore, Walnut Creek, Concord, and Discovery Bay. They see genuine summer heat — 95–105°F is common in July and August. Insulation in these zones is critical for cutting cooling load. The same R-38 minimum applies. But the savings payback is faster inland, because the heat gap between attic and living space is larger.
Further inland — Stockton, Ripon, Tracy, Manteca — summer highs regularly exceed 100°F. Attic temperatures routinely hit 140–160°F. In these zones, R-38 is a code minimum, not an aspiration. Consider R-49, or spray foam that conditions the attic envelope, if your HVAC ducts run through the attic. They do in most 1960s–1980s construction.
Insulation Types — What NuShake Installs and Why
Blown-in fiberglass — the standard
Blown-in fiberglass is the most common attic insulation for good reason. It installs fast and settles very little over time. It resists fire by nature, with no added fire retardants. And it handles the Bay Area's moisture cycles well. Owens Corning EcoTouch and CertainTeed InsulSafe are the products NuShake uses most. Both are R-2.5 per inch, so R-38 needs about 15 inches of depth.
Blown-in cellulose — the dense-pack option
Cellulose is denser than fiberglass and slightly better at air-sealing in tight applications. It is made from recycled paper and carries fire retardants. The tradeoffs: it settles 10–20% over time (reducing R-value), and it is more susceptible to moisture damage than fiberglass. For open attic floor applications in ventilated attics, fiberglass is generally preferred in the Bay Area's damp coastal zones. Cellulose may make sense for specific applications or homeowner preferences.
Spray foam — the premium option
Closed-cell or open-cell spray foam applied to the underside of the roof deck (not the attic floor) creates an unventilated, conditioned attic. This is the top-performance option when HVAC ducts run through the attic. It brings the ducts into the conditioned space and ends duct loss entirely. Cost is roughly 3–4x blown-in. For homes with attic ducts and high cooling loads, the energy savings often justify the premium in 5–10 years.
Batts — DIY-friendly but limited for upgrades
Kraft-faced or unfaced fiberglass batts are familiar and easy to handle, which makes them popular for DIY projects. For whole-attic upgrades, blown-in is almost always more practical. It fills around joists, blocking, and obstructions without cutting and fitting each piece. Batts work well in specific cases, like adding a second layer in a regular joist pattern. But blown-in wins for speed, coverage, and cost on a full upgrade.
R-Value Math — The 30-Second Version
R-value is additive. Say you have existing R-11 batts — about 4 inches of old fiberglass. Add R-30 of blown-in on top and your total is about R-41. That is above the R-38 code minimum.
The practical steps:
- Measure existing insulation depth. Divide by the R-value per inch for the material type. That gives you current effective R-value.
- Subtract from R-38 (or R-49 if targeting high performance). That is how much you need to add.
- Divide the additional R-value needed by the R-value per inch of the new material (R-2.5/inch for blown-in fiberglass). That gives you the inches to add.
Example: existing 4 inches of compressed old fiberglass at R-2/inch = R-8 effective. Need R-38. Must add R-30. At R-2.5/inch blown-in, that is 12 inches of new blown-in. Total depth after upgrade: 16 inches. Total R-value: approximately R-38.
NuShake measures existing insulation and confirms the required depth during the free inspection. You do not need to calculate this yourself.
PG&E Rebates for Title 24-Compliant Insulation Upgrades
PG&E participates in California's statewide energy efficiency programs. The Energy Upgrade California and TECH Clean California programs both offer rebates for qualifying attic insulation upgrades. Typical rebate amounts run 10–30% of project cost for Title 24-compliant work.
Rebate eligibility has three requirements. A licensed contractor must do the work. The materials must meet set performance standards. And documentation must be submitted through the program portal. NuShake provides the product data sheets, installation records, and any compliance forms your rebate application needs.
Rebate programs change — available funding is allocated and can run out during the year. Brian confirms current rebate availability at the time of your project. The general principle holds: Title 24-compliant insulation work by a licensed contractor typically qualifies for some level of PG&E incentive.
PG&E rebates stack with the NuShake bundle discount. Do a roof replacement and add attic insulation at the same time, and you get a 10–15% discount on the insulation portion from NuShake. You may also qualify for PG&E rebates on the same work. That combination cuts the real cost of the insulation upgrade substantially.
Why NuShake Does Insulation When Most Roofers Do Not
Most roofing contractors do not offer insulation. They specialize in the exterior assembly — shingles, underlayment, flashing — and leave attic work to separate insulation subcontractors or HVAC companies.
NuShake has offered insulation as part of roofing work since Doug Heath founded the company in 1976. The logic is straightforward: the roof and the attic insulation are the same thermal envelope. A roofer who sees the attic during a re-roof and does not address the insulation is leaving unfinished business. The customer pays for two mobilizations, two permits in some jurisdictions, and misses the window when the work is cheapest.
Brian has worked every role: tear-off crew at 18, crew lead at 20, lead salesman at 22, licensed owner at 23. Along the way he has personally been in hundreds of attics. He knows what degraded insulation looks like. He knows what ventilation problems look like. In a single inspection visit, he can tell you what your attic actually needs, not what a sales-first pitch would push. Insulation and airflow work as a pair. Our attic ventilation guide explains why one without the other can trap moisture and shorten the life of your roof deck.
The insulation service page covers the full scope of what NuShake installs. For solar insulation interaction (the cool-roof connection), see the solar roofing hub.
The Bundle Discount — 10–15% Off Insulation with Roof Replacement
When you replace your roof and upgrade your attic insulation as a single NuShake project, the insulation portion is discounted 10–15%. The reason is straightforward: the labor overhead of a second mobilization (trucks, crew time, staging equipment) is eliminated. We are already on site. The marginal cost of adding insulation work drops significantly.
This discount is not available if you schedule insulation separately from the roofing project. The bundle must be contracted together. Most homeowners who learn about this discount do not choose to separate the projects after hearing the economics.
Now add PG&E rebate eligibility. The real cost of insulation in a NuShake bundle project can run 20–40% below a standalone insulation job from a separate contractor.
Not in the Bay Area or northern Central Valley? Our sister brands cover the rest of the family territory. Econo Roofing (Mario Espindola's flagship) covers south Central Valley — Fresno, Clovis, Madera, Merced. DeHart Roofing covers Stanislaus County core (Modesto, Turlock, Ceres, Oakdale). Same family approach to insulation bundling applies across all three brands.
Frequently Asked Questions — Title 24 and Bay Area Insulation
What R-value does Title 24 require for attic insulation in the Bay Area?
The 2022 California Energy Code requires R-38 minimum for attic insulation in most Bay Area climate zones. R-49 is the high-performance standard and required for some new construction. The exact requirement depends on your climate zone number. NuShake confirms your zone and current insulation level during the free inspection.
My home was built in the 1960s. What insulation do I probably have?
Homes from 1950–1975 typically have R-11 to R-19 of attic insulation — if any was installed at all. That compressed 50-year-old fiberglass may be performing at R-6 or R-7 in practice. R-38 is three to six times better. Upgrading typically reduces heating and cooling energy use by 15–25% for Bay Area homes.
Do I have to upgrade insulation when I re-roof?
Title 24 requires an energy compliance check as part of most roofing permits. If your attic insulation is below current code minimums, you may be required to upgrade it as a condition of permit approval. This varies by jurisdiction. Brian knows which Bay Area cities are strict on this requirement and handles the compliance documentation as part of the permit application.
What PG&E rebates are available for insulation upgrades?
PG&E's Energy Upgrade California and TECH Clean California programs offer rebates for qualifying insulation upgrades. These typically run 10–30% of project cost for Title 24-compliant work by a licensed contractor. NuShake provides the documentation needed to file. Brian confirms current rebate availability at the time of your project, since funding changes seasonally.
What is the difference between blown-in fiberglass and blown-in cellulose?
Both are effective. Blown-in fiberglass settles very little, resists fire by nature, and handles the Bay Area's moisture cycles well. It is the standard choice for ventilated attic floors. Blown-in cellulose is denser and slightly better at air-sealing. But it settles 10–20% over time and takes on moisture more easily. Fiberglass is the default pick for most Bay Area attic upgrades.
Should I add insulation over existing batts or remove them first?
In most cases, blown-in can go over existing batts without removal. The catch is that the old insulation must be dry, undamaged, and clean. If it is wet, compressed significantly, or contaminated with mold or rodent debris, removal is required. NuShake inspects the attic before every project to assess whether removal is necessary.
Does adding attic insulation affect attic ventilation?
Yes — it must not block soffit vents. NuShake installs insulation baffles at the eaves to maintain the ventilation channel as blown-in insulation is added. Blocked soffits cause moisture buildup and can lead to roof deck damage. This is one of the most common installation errors by non-roofer insulation crews. A roofer doing insulation understands the ventilation system because they installed it.
When is spray foam worth the cost?
When your HVAC ducts run through the attic. Spray foam on the roof deck brings the attic into the conditioned space. The ducts no longer lose energy through hot attic air. The premium runs roughly 3–4x the blown-in cost. It pays back faster when you cut duct loss, which can be 20–30% of HVAC energy in a hot zone like Stockton or Livermore.
Does NuShake do wall insulation?
No. NuShake specializes in attic insulation as part of the roof and thermal envelope system. Wall insulation needs different equipment and expertise, so it is not in our scope. We focus on the attic for two reasons. It is where the largest R-value gap sits in most Bay Area homes. And it is where we can work most efficiently alongside a roof replacement.
Ready to see how your attic measures up?
Free inspection includes attic depth measurement, R-value assessment, ventilation check, and Title 24 compliance status. Bundle insulation with your roof replacement for 10–15% off plus potential PG&E rebates.
Brian Espindola · Owner · CSLB #1142280 · GAF Master Elite · CertainTeed Select ShingleMaster · Owens Corning Preferred