Roof internal lining is the often-overlooked hero of building performance. While homeowners focus on shingles and membranes, the interior components—vapor barriers, insulation, and thermal liners—determine your home's energy efficiency, comfort, and protection against moisture damage. In Myrtle Beach's humid coastal climate, proper internal lining isn't optional—it's essential.
This comprehensive guide covers everything from basic vapor barrier principles to advanced thermal systems. Whether you're building new, replacing a roof, or upgrading an existing system, you'll learn exactly what your property needs and why. With 73 five-star reviews and thousands of roof installations in coastal South Carolina, WeatherShield Roofing has seen firsthand how proper internal lining prevents costly moisture damage and slashes energy bills.
1. What is Roof Internal Lining?
Roof internal lining encompasses all the interior-facing components of your roofing system—the layers you'd see if you looked up from your attic or the underside of a flat roof. Unlike external roofing materials that shed water, internal lining systems manage heat, moisture, and air movement within the roof assembly.
The 5 Primary Functions of Internal Lining
- Thermal Control: Insulation reduces heat transfer, keeping interiors cool in summer and warm in winter
- Moisture Management: Vapor barriers prevent humid air from reaching cold surfaces where condensation forms
- Air Sealing: Continuous air barriers stop conditioned air from escaping and outdoor air from infiltrating
- Fire Protection: Fire-rated linings slow flame spread and provide evacuation time in emergencies
- Structural Support: Some linings (like OSB or plywood) provide racking strength and nail-base for finishes
Internal Lining vs. Underlayment: What's the Difference?
Many homeowners confuse internal lining with roof underlayment. Here's the distinction:
| Feature | Roof Underlayment | Internal Lining |
|---|---|---|
| Location | Above roof deck, below shingles | Below roof deck, facing interior |
| Primary Purpose | Water protection backup | Thermal & moisture control |
| Materials | Felt, synthetic, ice & water shield | Vapor barriers, insulation, radiant barriers |
| Visibility | Hidden under roofing material | Often visible from attic |
| Code Focus | Water resistance | Energy efficiency (R-value) |
2. 8 Types of Internal Lining Systems
Different buildings and climates require different internal lining strategies. Here are the 8 main types used in residential and commercial roofing:
1. Polyethylene Vapor Barriers
The most common vapor barrier material—6-mil polyethylene sheeting installed on the warm side of insulation. Prevents moisture-laden air from entering the roof cavity.
Specifications:
- • Thickness: 4-mil to 10-mil
- • Perm Rating: 0.06 perms (Class I)
- • Cost: $0.10-$0.25/sq ft material
- • Lifespan: 20+ years
Best For:
- • Cold climates with heating-dominant loads
- • New construction with controlled installation
- • Budget-conscious projects
2. Smart Vapor Retarders
Variable-permeance membranes that adapt to humidity levels—becoming more permeable in summer to allow drying and less permeable in winter to block vapor. Ideal for mixed climates like Myrtle Beach.
Specifications:
- • Perm Rating: 1-10 perms (variable)
- • Brands: CertainTeed MemBrain, Pro Clima Intello
- • Cost: $0.50-$1.00/sq ft material
- • Lifespan: 30+ years
Best For:
- • Mixed heating/cooling climates
- • Coastal humid regions (Myrtle Beach)
- • Retrofit applications
Coastal Recommendation: Smart vapor retarders are our top recommendation for Myrtle Beach. They prevent winter condensation while allowing summer moisture to escape—critical with 75%+ average humidity.
3. Fiberglass Batt Insulation
Traditional insulation fitted between rafters or ceiling joists. Cost-effective but requires careful installation to prevent gaps and compression that reduce R-value.
Specifications:
- • R-Value: R-3.2 to R-3.8 per inch
- • Thickness for R-38: 10-12 inches
- • Cost: $0.50-$1.50/sq ft installed
- • Lifespan: 80-100 years (if dry)
Limitations:
- • Loses R-value when wet
- • Doesn't stop air movement
- • Can settle over time
4. Spray Foam Insulation
Liquid foam sprayed onto surfaces that expands to fill cavities. Provides both insulation and air sealing in one application. Available in open-cell (lower R-value, vapor permeable) and closed-cell (higher R-value, vapor barrier) formulations.
Open-Cell Foam:
- • R-Value: R-3.5 to R-3.7 per inch
- • Cost: $1.00-$2.00/sq ft (3" thick)
- • Vapor Permeable: Yes (allows drying)
- • Best for: Interior applications, sound control
Closed-Cell Foam:
- • R-Value: R-6.0 to R-7.0 per inch
- • Cost: $2.50-$4.00/sq ft (2" thick)
- • Vapor Barrier: Yes (Class II at 2")
- • Best for: Roof decks, structural enhancement
Important: Closed-cell spray foam applied directly to roof decking creates unvented assemblies. This eliminates traditional attic ventilation but requires careful moisture analysis—especially in coastal environments.
5. Rigid Foam Board Insulation
Solid foam panels (EPS, XPS, or polyiso) installed above or below roof decking. Continuous insulation eliminates thermal bridging through rafters—a major source of heat loss.
| Type | R-Value/Inch | Cost/Sq Ft | Best Use |
|---|---|---|---|
| EPS (Expanded Polystyrene) | R-3.6 to R-4.2 | $0.25-$0.50 | Budget applications |
| XPS (Extruded Polystyrene) | R-5.0 | $0.50-$0.90 | Moisture-prone areas |
| Polyisocyanurate (Polyiso) | R-5.6 to R-6.5 | $0.70-$1.20 | Above-deck, flat roofs |
6. Radiant Barriers
Reflective materials (usually aluminum foil) that block radiant heat transfer. Unlike insulation that slows conductive heat, radiant barriers reflect up to 97% of radiant heat—making them exceptionally effective in hot climates like Myrtle Beach.
Types:
- • Foil-faced OSB or plywood
- • Reflective bubble wrap
- • Staple-up foil sheets
- • Spray-on reflective coatings
Performance:
- • Reduces attic temp by 20-30°F
- • Cuts cooling costs 5-15%
- • Cost: $0.15-$0.75/sq ft
- • Most effective with air gap
Myrtle Beach Tip: Radiant barriers are highly cost-effective here. Our summer sun angle and 90°F+ temperatures mean attics often reach 140-160°F. A properly installed radiant barrier can drop this to 90-110°F, dramatically reducing AC loads.
7. Fire-Rated Interior Linings
Required in commercial buildings and some residential applications, fire-rated linings provide a specific fire resistance rating (measured in hours). Common in multi-family buildings, garages, and attached structures.
Common Materials:
- • 5/8" Type X Gypsum Board: 1-hour rating
- • Double-layer Type X: 2-hour rating
- • Mineral fiber boards: Class A fire rated
- • Intumescent coatings: Expands when heated
Required Applications:
- • Attached garage ceilings
- • Multi-family common areas
- • Commercial buildings
- • Within 3ft of property lines
8. Composite Lining Systems
Pre-manufactured panels combining multiple functions—typically insulation, vapor barrier, and finish surface in one product. Popular in commercial flat roofing and modern residential construction.
Examples:
- • Insulated metal panels (IMP)
- • Structural insulated panels (SIPs)
- • Foil-faced polyiso boards
- • Pre-finished ceiling panels
Advantages:
- • Faster installation
- • Fewer on-site coordination issues
- • Consistent quality control
- • Single-source warranty
3. Vapor Barriers Explained: The Science of Moisture Control
Understanding vapor barriers requires understanding how moisture moves through building assemblies. Warm air holds more moisture than cold air—and when warm, humid air contacts cold surfaces, water condenses. This condensation inside roof cavities causes mold, rot, and insulation failure.
Vapor Barrier Classifications
Building codes classify vapor retarders by their permeance—how readily they allow water vapor to pass through, measured in "perms":
| Class | Perm Rating | Examples | Typical Use |
|---|---|---|---|
| Class I (Impermeable) | ≤0.1 perms | Polyethylene sheet, aluminum foil, glass | Cold climates (heating dominant) |
| Class II (Semi-Impermeable) | 0.1 - 1.0 perms | Kraft-faced insulation, some paints | Moderate climates |
| Class III (Semi-Permeable) | 1.0 - 10 perms | Latex paint, building paper, OSB | Mixed climates (Myrtle Beach) |
Vapor Barrier Placement: The Great Debate
Where to place vapor barriers depends entirely on your climate and building use:
Cold Climates (Heating Dominant)
Vapor barrier on INTERIOR side
- • Prevents warm indoor air from reaching cold roof deck
- • Allows exterior moisture to dry outward
- • Example: Maine, Minnesota
Hot-Humid Climates (Cooling Dominant)
Vapor barrier on EXTERIOR side
- • Prevents outdoor humid air from reaching cold AC-cooled surfaces
- • Allows interior moisture to dry inward
- • Example: Miami, Houston
Myrtle Beach: The Mixed Climate Challenge
Myrtle Beach sits in Climate Zone 3—a mixed climate that needs heating in winter and cooling in summer. This creates a vapor drive problem: in winter, moisture wants to move outward (like cold climates); in summer, moisture wants to move inward (like hot climates).
Solution: Use Class III vapor retarders (semi-permeable) or smart vapor retarders that allow bi-directional drying. Avoid Class I barriers (like 6-mil poly) which can trap moisture in summer.
4. Thermal Insulation Options for Roof Assemblies
Thermal insulation is rated by R-value—the measure of resistance to heat flow. Higher R-values mean better insulation. South Carolina building codes require specific R-values based on climate zone and assembly type.
South Carolina R-Value Requirements (2025 IECC)
| Assembly Type | Minimum R-Value | Recommended (Coastal SC) |
|---|---|---|
| Attic (ceiling insulation) | R-38 | R-49 to R-60 |
| Cathedral ceiling (all insulation below deck) | R-30 | R-38 to R-49 |
| Roof with insulation above deck | R-20 | R-25 to R-30 |
| Commercial flat roof | R-20 continuous | R-25 to R-30 |
Why Exceed Code Minimum?
In Myrtle Beach's hot summers, every additional R-value point reduces cooling costs. Going from R-38 to R-49 in attics typically costs $500-$1,000 more but saves $100-$200 annually on cooling—a 5-year payback. With energy costs rising, the investment becomes even more attractive over time.
Insulation Comparison Chart
| Insulation Type | R/Inch | Installed Cost | Air Barrier? | Moisture Resistant? | Coastal Rating |
|---|---|---|---|---|---|
| Fiberglass Batts | R-3.2 | $0.50-$1.50/sf | No | No | Fair |
| Blown Fiberglass | R-2.5 | $1.00-$2.00/sf | No | No | Fair |
| Cellulose | R-3.5 | $1.00-$1.75/sf | Partial | No | Good |
| Open-Cell Spray Foam | R-3.6 | $1.50-$2.50/sf | Yes | No | Good |
| Closed-Cell Spray Foam | R-6.5 | $3.00-$5.00/sf | Yes | Yes | Excellent |
| Polyiso Board | R-6.0 | $1.50-$2.50/sf | Partial | Yes | Excellent |
| XPS Board | R-5.0 | $1.25-$2.00/sf | Partial | Yes | Excellent |
5. Radiant Barriers for Hot Climates
Radiant barriers work differently than insulation. While insulation slows conductive heat transfer, radiant barriers reflect radiant heat—the infrared energy that radiates from hot surfaces like sun-heated roofing materials.
How Radiant Barriers Work
On a 95°F summer day in Myrtle Beach, your roof surface can reach 150-170°F. This hot roof radiates heat downward into your attic. Without intervention, attic temperatures soar to 140-160°F—superheating the air that eventually conducts through your ceiling insulation.
Radiant barriers with low emissivity (0.03-0.05) reflect 95-97% of this radiant heat back toward the roof, dramatically reducing attic temperatures. The result: your ceiling insulation faces 90-110°F instead of 140-160°F, slashing heat gain into living spaces.
Radiant Barrier Installation Methods
1. Rafter-Space Installation (Draped or Stapled)
Radiant barrier foil stapled to underside of rafters or draped between trusses.
- Pros: Retrofit-friendly, cost-effective
- Cons: Can collect dust, reduces effectiveness over time
- Cost: $0.15-$0.50/sq ft installed
- Effectiveness: 25-40% heat reduction
2. Roof Deck Application (Attached to Deck)
Radiant barrier attached directly to underside of roof deck during new construction or re-roofing.
- Pros: Most effective, no dust accumulation
- Cons: Requires roof work to install
- Cost: $0.30-$0.75/sq ft installed
- Effectiveness: 30-45% heat reduction
3. OSB/Plywood with Integrated Barrier
Radiant barrier laminated to roof sheathing during manufacturing (e.g., LP TechShield, Georgia-Pacific Thermostat).
- Pros: Permanent, one-step installation
- Cons: Only for new construction/full re-sheath
- Cost: $0.35-$0.60/sq ft premium over standard OSB
- Effectiveness: 35-45% heat reduction
4. Spray-On Reflective Coatings
Liquid ceramic or aluminum-based coatings sprayed on roof deck underside.
- Pros: No joints, covers irregular surfaces
- Cons: Less reflective than foil, requires proper application
- Cost: $0.50-$1.00/sq ft installed
- Effectiveness: 20-30% heat reduction
ROI for Myrtle Beach Homeowners
For a 2,000 sq ft home with average $200/month summer electric bills, a properly installed radiant barrier typically reduces cooling costs by 5-15%—saving $120-$360 annually. With installation costs of $300-$1,000 for a retrofit, payback occurs in 1-3 years. Combined with adequate attic insulation (R-49+), total cooling savings can reach 20-30%.
6. Fire-Rated Linings
Fire-rated interior linings slow flame spread and provide occupants evacuation time. Required by building codes in specific applications, they're rated by time (1-hour, 2-hour) indicating how long the assembly maintains structural integrity during fire exposure.
When Fire-Rated Linings Are Required
Residential Requirements
- Attached garage ceilings: 1/2" gypsum minimum, 5/8" Type X for living space above
- Townhouse separation walls: 1-hour rated to roof deck
- Furnace rooms: 1-hour rated enclosure
- Attic access in garages: Fire-rated assembly
Commercial Requirements
- Multi-tenant buildings: 1-2 hour rated roof/ceiling assemblies
- Corridor ceilings: 1-hour rated for egress protection
- High-rise buildings: 2-hour rated floor/ceiling assemblies
- Assembly occupancies: Class A or B interior finish required
Fire-Rated Material Options
| Material | Fire Rating | Typical Application | Cost |
|---|---|---|---|
| 1/2" Regular Gypsum | 30 minutes | Basic garage ceiling | $0.35-$0.50/sq ft |
| 5/8" Type X Gypsum | 1 hour | Garage with living above | $0.45-$0.65/sq ft |
| Double Layer Type X | 2 hours | Commercial separation | $0.90-$1.30/sq ft |
| Mineral Fiber Panels | Class A (0-25 FSI) | Commercial ceilings | $2.00-$4.00/sq ft |
| Intumescent Coating | 1-2 hours | Steel/wood protection | $3.00-$8.00/sq ft |
7. Myrtle Beach Coastal Considerations
Coastal South Carolina presents unique challenges for roof internal lining systems. High humidity, salt air, hurricane winds, and extreme temperature swings require specialized approaches not needed in typical inland installations.
Humidity Challenges
- Average Humidity: 75-85% year-round
Higher than national average of 60-65%
- Dew Point Risk: Frequent 70°F+ dew points
Condensation occurs whenever surfaces drop below this
- Vapor Drive: Bi-directional (summer inward, winter outward)
Requires smart vapor management, not rigid barriers
- Mold Risk: High (Category 4 on EPA scale)
Any moisture intrusion promotes rapid mold growth
Environmental Stressors
- Salt Air Corrosion: Within 1 mile of coast
Metal fasteners, foil barriers need corrosion resistance
- Hurricane Pressure: Rapid pressure differentials
Air barriers must withstand without tearing
- Temperature Swings: 30°F daily swings common
Materials must handle expansion/contraction
- UV Exposure: High solar index
Any exposed barriers need UV resistance
Coastal-Specific Recommendations
1. Use Smart Vapor Retarders Instead of Poly Sheeting
Products like CertainTeed MemBrain or Pro Clima Intello adapt to humidity, allowing seasonal drying while blocking vapor when needed.
2. Specify Moisture-Resistant Insulation
Closed-cell spray foam, XPS, or properly faced polyiso resist moisture absorption. Avoid open-cell foam or unfaced fiberglass in high-risk areas.
3. Install Radiant Barriers with Air Gaps
Radiant barriers work best with 1"+ air gap. Ensure installation maintains gap and uses stainless steel or aluminum staples for coastal corrosion resistance.
4. Maintain Proper Ventilation
Even with vapor barriers, coastal humidity requires robust attic ventilation—minimum 1:150 ratio (1 sq ft vent per 150 sq ft attic).
5. Seal All Penetrations
Every wire, pipe, and HVAC penetration is a potential moisture pathway. Use appropriate sealants rated for humidity and temperature cycling.
8. Installation Methods: New Construction vs. Retrofit
New Construction Installation
Building from scratch allows optimal layering and integration:
- Install roof deck (OSB/plywood, optionally with radiant barrier)
- Apply air barrier/vapor retarder to deck underside if using unvented assembly
- Install insulation (spray foam, batts, or rigid board)
- Apply interior vapor retarder (if required by climate)
- Install interior finish (gypsum, T&G, exposed beams)
Key advantage: All layers accessible, proper sequencing ensured
Retrofit Installation
Upgrading existing roofs requires creative solutions:
- Assess existing insulation and vapor barriers
- Add blown insulation to attic floor (if vented assembly)
- Install radiant barrier on rafter undersides
- Spray foam underside of deck (creates unvented assembly)
- Or: Add rigid foam below rafters with vapor retarder
Key challenge: Working with existing structure, maintaining ventilation
Critical Installation Principle
Never install two vapor barriers. A common mistake is adding new vapor-impermeable insulation over existing vapor barriers—this traps moisture between layers. Before any retrofit, assess what vapor control already exists and design additions accordingly.
9. Building Code Requirements (2025 IECC)
South Carolina follows the International Energy Conservation Code (IECC) with state amendments. Myrtle Beach falls in Climate Zone 3, which has specific requirements for insulation, air barriers, and vapor control.
Key Code Requirements for Myrtle Beach (Climate Zone 3)
Insulation Requirements
- • Ceiling/Attic: R-38 minimum
- • Cathedral Ceiling: R-30 minimum
- • Roof with above-deck insulation: R-20
- • Commercial roof: R-20 continuous insulation
Air Barrier Requirements
- • Continuous air barrier required
- • Maximum air leakage: 5 ACH50 (residential)
- • Maximum air leakage: 0.4 cfm/sq ft (commercial)
- • Sealing required at all penetrations
Vapor Retarder Requirements
- • Class I or II vapor retarder required on interior in Climate Zone 4+
- • Climate Zone 3 (Myrtle Beach): Not required but recommended
- • Smart vapor retarders acceptable in all zones
Ventilation Requirements
- • Vented attics: 1:150 net free area ratio
- • Can reduce to 1:300 with balanced high/low vents
- • Unvented assemblies: Air-impermeable insulation to deck
10. Cost Comparison Chart
Understanding the full cost picture helps you make informed decisions. This chart shows installed costs for a typical 1,500 sq ft roof area in Myrtle Beach (2025 pricing).
| Internal Lining System | Material Cost | Labor Cost | Total (1,500 sq ft) | Annual Energy Savings |
|---|---|---|---|---|
| 6-mil Poly Vapor Barrier Only | $150-$225 | $300-$500 | $450-$725 | $50-$100 |
| Smart Vapor Retarder (MemBrain) | $600-$900 | $400-$600 | $1,000-$1,500 | $75-$150 |
| Radiant Barrier (Stapled Foil) | $225-$375 | $400-$700 | $625-$1,075 | $150-$300 |
| Fiberglass Batts to R-38 | $750-$1,125 | $750-$1,125 | $1,500-$2,250 | $200-$400 |
| Blown Cellulose to R-49 | $900-$1,350 | $600-$900 | $1,500-$2,250 | $250-$450 |
| Open-Cell Spray Foam (5") | $2,250-$3,750 | Included | $2,250-$3,750 | $300-$500 |
| Closed-Cell Spray Foam (3") | $4,500-$7,500 | Included | $4,500-$7,500 | $400-$600 |
| Complete System (Radiant + R-49 + Smart Vapor) | $1,775-$2,850 | $1,350-$2,100 | $3,125-$4,950 | $400-$700 |
* Costs are estimates for Myrtle Beach area (2025). Actual costs vary by home configuration, accessibility, and specific products chosen.
11. 5-Step Inspection Checklist
Use this checklist to assess your roof's internal lining condition. Perform annually and after major storms.
Check Attic Temperature
On a hot day (85°F+), measure attic temperature. Compare to outdoor temperature.
- ✓ Attic <10°F above outdoor = Good insulation/radiant barrier
- ⚠ Attic 10-25°F above outdoor = Adequate but could improve
- ✗ Attic >25°F above outdoor = Insulation upgrade needed
Inspect for Moisture Signs
Look for water stains, mold, mildew, or rust on metal components.
- • Dark staining on rafters or sheathing
- • Mold or mildew odor
- • Rusted nails, straps, or HVAC components
- • Wet or discolored insulation
Any moisture signs require professional assessment
Measure Insulation Depth
Use a ruler to measure insulation thickness. Check multiple locations.
- • R-38 (code minimum) = 10-12" fiberglass or 9-10" cellulose
- • R-49 (recommended) = 13-14" fiberglass or 11-12" cellulose
- • Watch for settling, compression, or gaps near eaves
Check Vapor Barrier Integrity
Inspect any visible vapor barrier for tears, gaps, or improper installation.
- • Tears or punctures (from storage items, foot traffic)
- • Unsealed seams between sheets
- • Gaps around pipes, wires, and ductwork
- • Barrier on wrong side of insulation
Evaluate Ventilation
Ensure soffit and ridge vents are clear and functional.
- • Soffit vents unobstructed by insulation (use baffles)
- • Ridge vent or roof vents present and open
- • Balanced high/low ventilation (intake = exhaust)
- • Minimum 1 sq ft ventilation per 150 sq ft attic
12. Frequently Asked Questions
What is roof internal lining?
Roof internal lining refers to the interior-facing components of a roofing system that provide thermal insulation, vapor control, condensation prevention, and in some cases fire resistance. This includes vapor barriers, thermal insulation, radiant barriers, and interior finish materials. Internal lining protects against heat loss, moisture damage, and energy inefficiency.
Do I need a vapor barrier in my roof in Myrtle Beach?
In Myrtle Beach's humid subtropical climate, vapor barriers are essential but must be properly placed. For air-conditioned buildings, the vapor barrier typically goes on the interior (warm-in-summer) side. However, in mixed climates like coastal South Carolina, a smart vapor retarder that adapts to humidity levels is often the best choice to prevent condensation problems year-round.
What R-value is required for roof insulation in South Carolina?
South Carolina building codes (Climate Zone 3) require minimum R-38 for attic/ceiling insulation and R-20 for roof assemblies where insulation is entirely above the deck. For optimal energy efficiency in Myrtle Beach's hot summers, contractors often recommend R-49 to R-60 for attics, which can reduce cooling costs by 20-30%.
What's the difference between vapor barrier and radiant barrier?
Vapor barriers block moisture migration through roof assemblies to prevent condensation and mold. Radiant barriers reflect heat radiation (up to 97% of radiant heat) to keep buildings cooler. In Myrtle Beach, both are beneficial: vapor barriers prevent humidity damage while radiant barriers reduce summer cooling costs by 5-15%.
How much does roof internal lining installation cost?
Roof internal lining costs vary by type: Vapor barriers cost $0.50-$1.50 per square foot installed. Fiberglass batt insulation runs $1.00-$2.50/sq ft. Spray foam insulation costs $3.00-$7.00/sq ft. Radiant barriers range from $0.75-$1.25/sq ft. For a typical 1,500 sq ft roof in Myrtle Beach, complete internal lining upgrades range from $2,000-$12,000 depending on materials.
Can I add insulation to an existing roof without replacing it?
Yes, you can add insulation to existing roofs through several methods: blown-in insulation added to attic spaces, spray foam applied to underside of roof deck, rigid foam boards installed below rafters, or radiant barriers stapled to rafter undersides. The best method depends on your roof type, existing insulation, and ventilation requirements.
What causes condensation in roof assemblies?
Roof condensation occurs when warm, humid air contacts cold surfaces and reaches its dew point. Common causes include: inadequate vapor barriers allowing indoor humidity into roof cavities, insufficient ventilation preventing moisture escape, thermal bridging creating cold spots, and air leakage around penetrations. In Myrtle Beach, high humidity (75-85% average) makes proper vapor management critical.
How long does roof insulation last?
Roof insulation lifespan varies by type: Fiberglass batts last 80-100 years if kept dry. Spray foam insulation lasts 80+ years. Rigid foam boards last 50-75 years. Cellulose insulation lasts 20-30 years. However, moisture damage, pest infestation, or settling can significantly reduce effectiveness. In coastal areas, inspect insulation every 5-10 years for moisture damage.
Need a Professional Assessment of Your Roof's Internal Lining?
WeatherShield Roofing offers comprehensive attic and roof cavity inspections. We'll evaluate your insulation, vapor barriers, ventilation, and energy efficiency—and provide honest recommendations without pressure.
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