“Can you just put new shingles over the old ones?” We hear this question on nearly every roofing consultation. The appeal is obvious: skip the labor-intensive tear-off, save on disposal costs, and get a new-looking roof for less money. The short answer is yes, the Florida Building Code allows up to two layers of asphalt shingles on a roof.
The longer answer, and the one that matters, is that we almost never recommend it. Not because we want to sell a more expensive project (though tear-off does cost more), but because the specific conditions in Florida make a shingle overlay significantly riskier than it would be in a northern climate. The money you save upfront often comes back as problems that cost more to fix than the original tear-off would have.
This guide explains the full picture: what the code says, why overlay works poorly in Florida, when it might be acceptable, and how to make the right decision for your specific situation. Our detailed tear-off vs. overlay comparison covers additional scenarios.
What the Florida Building Code Actually Says
The Florida Building Code, Building Section 1511.3 (Recovering versus Replacement), establishes the rules for roofing over existing materials:
- Maximum two layers. A roof may have no more than two layers of any type of roof covering. If your roof already has two layers, any future work requires complete removal down to the deck.
- Existing condition requirement. The existing roof covering must be in sufficiently good condition to serve as a suitable substrate for the new covering. If the existing layer is deteriorated, buckled, or water-damaged, overlay is not permitted.
- Structural capacity. The roof structure must be capable of supporting the additional weight of the new layer. For asphalt shingles, this is typically 2 to 3 pounds per square foot of additional dead load.
- Product compatibility. The new roofing material must be approved for installation over existing roofing. Not all products carry this approval.
Additionally, the 25% rule applies to overlays just as it does to tear-offs. If you overlay more than 25% of your roof area within 12 months, the entire roof must meet current code. This creates a critical problem: current code in high-wind zones like Pinellas County requires sealed roof deck underlayment (peel-and-stick), which cannot be properly installed without removing the existing shingles to access the deck. In other words, if the 25% rule triggers on an overlay project, you may end up doing a tear-off anyway.
Why We Almost Never Recommend Overlay in Florida
The overlay technique works reasonably well in some parts of the country. In the northern United States, where temperatures are moderate, humidity is lower, and hurricanes are not a concern, a second layer of shingles can provide acceptable performance. Florida is not that environment. Here are the specific reasons overlay is problematic in our state.
1. Hidden Damage Goes Undetected
The most dangerous problem with an overlay is what you cannot see. When a roofer tears off the existing shingles, the bare deck is exposed and every square foot can be inspected. Rotted plywood, water-stained sheathing, cracked decking, corroded fasteners, and improperly flashed penetrations all become visible and can be addressed.
With an overlay, the existing shingles stay in place. The deck is never inspected. That slow leak around the plumbing vent that has been wetting the plywood for three years? It stays hidden under two layers of shingles, continuing to rot the deck from the top down. The corroded nail heads from the original installation? They remain, providing inadequate holding power for both the old and new layers.
In Pinellas County's humid subtropical climate, deck damage is far more common than homeowners realize. On approximately 90% of the tear-offs we perform, we find at least some deck replacement is needed. On overlay projects, this damage would remain hidden and worsen until it causes a visible failure, typically at the worst possible time, during a storm.
2. Moisture Trapping in Florida Humidity
Florida averages 54 inches of rainfall per year, and the relative humidity routinely exceeds 80%. This moisture must be able to escape from the roofing system to prevent mold, rot, and premature material degradation.
A single layer of shingles on a properly ventilated roof allows moisture to migrate through the system: up through the deck, through the underlayment, and out through the shingle surface. Adding a second layer creates an additional moisture barrier that traps dampness between the layers. This trapped moisture has nowhere to go. In Florida's heat, it cycles between liquid and vapor daily, creating a persistent wet environment that:
- Accelerates asphalt degradation from below (the bottom of the new shingles and the top of the old shingles both deteriorate)
- Promotes mold growth between layers (invisible but harmful to the structure and potentially to indoor air quality)
- Softens and degrades the roof deck over time, even if the deck was in good condition at the time of the overlay
- Reduces the new shingles' effective lifespan by 15 to 20% compared to the same shingles installed on a clean, dry deck
3. Excessive Heat Buildup
A roof surface in direct Florida sunlight can reach 160 to 180 degrees Fahrenheit on a summer day. Asphalt shingles are designed to handle this heat, but they are designed to do so with proper ventilation pulling heat away from below.
A second layer of shingles acts as insulation, trapping heat between the layers. The bottom of the new shingles and the top of the old shingles experience temperatures even higher than the surface because the heat has no efficient escape path. This accelerated thermal cycling causes:
- Faster granule loss on the new shingles (the primary UV protection wears off sooner)
- Premature brittleness and cracking
- Seal strip failure (the adhesive strip that bonds shingles together to resist wind softens and re-bonds improperly in excessive heat)
- Reduced energy efficiency (more heat transfers through to the attic, increasing cooling costs)
4. Wind Uplift Vulnerability
This is the factor that concerns us most in Pinellas County. During a hurricane, wind creates negative pressure (suction) on the roof surface that tries to lift shingles away from the deck. The resistance to this force depends on:
- The strength of the nail attachment (how well each nail grips the deck)
- The seal strip bond between overlapping shingles
- The weight of the shingle pressing down against the uplift force
With an overlay, the new shingles are nailed through the old shingles into the deck. This means the nail must penetrate two layers of asphalt before reaching the plywood. The additional material reduces the nail's effective penetration depth into the deck, weakening its holding power. In hurricane conditions, this reduced grip can mean the difference between shingles staying in place and lifting off in sheets.
Additionally, the added weight of two layers does not help with wind resistance the way you might expect. The weight is distributed across the surface, but wind uplift is concentrated at edges, corners, and ridge lines. At these vulnerable points, the doubled weight is negligible compared to the wind forces, but the reduced nail grip is significant.
For a community in the 140 to 150 mph design wind speed zone (which includes all of Pinellas County), this wind uplift risk alone is reason enough to recommend tear-off over overlay.
5. Reduced Warranty Coverage
Most major shingle manufacturers offer their best warranties only when shingles are installed on a clean, properly prepared deck. An overlay installation typically voids the enhanced warranty programs and limits you to the basic material warranty. Here is what that means in practice:
| Warranty Type | Tear-Off Installation | Overlay Installation |
|---|---|---|
| GAF Golden Pledge | 50-year material + 25-year workmanship | Not available |
| GAF Silver Pledge | 50-year material + 10-year workmanship | Not available |
| GAF Standard | Lifetime limited material | Reduced coverage, prorated |
| CertainTeed SureStart Plus | Full coverage first 10-25 years | Not available |
| Owens Corning Preferred Protection | Lifetime limited + workmanship | Material only, heavily prorated |
Losing the enhanced warranty means losing workmanship coverage (the most valuable component, since it covers installation errors), losing non-prorated coverage periods, and sometimes losing the warranty entirely if the manufacturer determines the overlay contributed to the failure.
6. Insurance Complications
Florida's insurance market has tightened significantly in recent years, and many carriers now scrutinize roof condition more carefully than ever. A two-layer roof creates several insurance problems:
- Insurability. Some carriers will not write new policies on homes with two layers of shingles. Others will write the policy but exclude the roof or add an actual cash value (ACV) roof endorsement instead of replacement cost value (RCV).
- Claim disputes. When storm damage occurs on a two-layer roof, the adjuster must determine which layer was damaged and whether the overlay contributed to or masked pre-existing problems. This creates ambiguity that can delay or reduce claim payments.
- Wind mitigation credits. A roof overlay may not qualify for the same wind mitigation credits as a proper tear-off and replacement, because the inspector cannot verify deck attachment or sealed roof deck underlayment. This means higher premiums for the life of the roof.
- Premium increases. Even when a carrier insures a two-layer roof, the premium is often higher than for a single-layer roof of the same age and material, because the two-layer roof is considered higher risk.
In a state where insurance costs are already among the highest in the nation, adding unnecessary premium through a two-layer roof is hard to justify.
The Real Cost Comparison: Overlay vs. Tear-Off
The appeal of overlay is the upfront savings. But when you factor in the full lifecycle costs, the picture changes dramatically.
Upfront Cost Comparison
| Cost Component | Overlay | Tear-Off | Difference |
|---|---|---|---|
| Tear-off labor | $0 | $1,000-2,500 | $1,000-2,500 savings |
| Disposal (dumpster + dump fees) | $0 | $400-800 | $400-800 savings |
| New shingles + installation | $7,000-14,000 | $7,000-14,000 | Same |
| Underlayment | Basic felt only | Peel-and-stick (SWR) | $800-2,000 more for tear-off |
| Deck inspection/repair | Not possible | $0-4,000 (as needed) | Variable |
| Total Upfront | $7,000-14,000 | $9,500-18,000 | $1,500-3,000 savings for overlay |
Lifecycle Cost Comparison (25-Year Period)
| Factor | Overlay | Tear-Off |
|---|---|---|
| Initial cost | $7,000-14,000 | $9,500-18,000 |
| Expected lifespan | 17-22 years | 25-30 years |
| Annual insurance premium difference | $0-500/year higher | Baseline |
| Wind mitigation credits lost | $500-2,000/year | Full credits available |
| Next replacement cost (tear-off 2 layers) | $11,000-20,000 | $9,500-18,000 |
| Next replacement timing | 17-22 years | 25-30 years |
| 25-Year Total Cost | $25,000-55,000 | $9,500-18,000 |
When you include the shorter lifespan, lost insurance credits, higher premiums, and the more expensive tear-off of two layers at the next replacement, the overlay's $1,500 to $3,000 upfront savings becomes a $15,000 to $37,000 long-term additional cost. The savings is an illusion.
The 25% Rule Complication
The Florida 25% rule creates a specific problem for overlay projects that many homeowners and even some contractors overlook.
If your overlay covers more than 25% of the total roof area (which a full overlay obviously does), the entire roof must comply with the current Florida Building Code. Current code in Pinellas County's high-wind zone requires:
- Sealed roof deck (SWR). Self-adhering modified bitumen underlayment applied directly to the roof deck. This cannot be properly installed over existing shingles, it must go on the bare deck.
- Current fastening schedule. Enhanced nailing patterns for the design wind speed zone, which are difficult to verify and execute properly through two layers of material.
- Florida product-approved materials. Both the shingles and underlayment must carry current Florida Product Approval numbers.
- Proper drip edge. Current code requires Type D or F drip edge on all eave and rake edges.
The SWR requirement is the deal-breaker. In Pinellas County, you cannot achieve a code-compliant overlay because the sealed roof deck requirement demands access to the bare deck surface. This means that any full overlay in Pinellas County technically triggers the 25% rule, which then requires tear-off to install SWR, which eliminates the overlay entirely.
Some contractors try to work around this by arguing that the overlay is a “re-cover” rather than a “replacement,” but building inspectors in Pinellas County generally do not accept this distinction for 25% rule purposes. If your inspector requires SWR compliance, the overlay is off the table.
When Overlay Might Be Acceptable
Despite everything above, there are narrow circumstances where an overlay can be a reasonable choice. All of the following conditions must be met:
- Single existing layer only. The current roof has one layer of shingles. If there are already two layers, tear-off is the only option.
- Existing shingles in good structural condition. The existing layer is flat (no curling or buckling), has no signs of water damage, and provides a stable substrate for new shingles. Minor cosmetic wear is acceptable, but the shingles must be lying flat.
- No evidence of deck damage. Attic inspection from below shows no water staining, no soft spots in the deck, no visible mold, and no corroded fastener points.
- Budget constraint is genuine. The homeowner has a real financial limitation that makes the $1,500 to $3,000 difference between overlay and tear-off the deciding factor. If the budget allows for tear-off, always choose tear-off.
- Short-term ownership. If you plan to sell within 5 to 7 years, an overlay may bridge the gap until the next owner handles a full replacement. Be aware this may affect resale value and buyer inspection findings.
- Building inspector approves. The Pinellas County inspector must sign off on the overlay as code-compliant, including the 25% rule implications discussed above.
Proper Overlay Technique (If You Proceed)
If you and your contractor determine that an overlay is the right choice for your specific situation, proper technique matters even more than usual. Cutting corners on an overlay compounds the inherent disadvantages.
- Remove all ridge caps and hip caps. The old ridge and hip caps must be stripped even in an overlay, because double layers at these critical wind-vulnerable points create unacceptable thickness and reduce the new cap's seal strip contact.
- Remove all valley flashing and re-flash. Valleys must be stripped to the deck and re-flashed with new metal or ice-and-water shield. Overlaying valleys traps debris and water between layers.
- Replace all pipe boots and penetration flashing. Old pipe boots and flashing cannot be effectively covered. They must be removed and replaced.
- Install new drip edge. Even in an overlay, current code requires proper drip edge on all eave and rake edges. The old drip edge (if present) must be removed and replaced.
- Use longer nails. Overlay installations require longer nails that penetrate both layers and still achieve adequate depth into the deck. Standard 1-1/4 inch nails are not sufficient. Use 1-3/4 to 2 inch nails minimum.
- Address uneven surfaces. If the existing shingles have any cupped, curled, or buckled areas, these must be cut flat or removed before overlaying. Nailing new shingles over uneven substrate guarantees premature failure.
What Happens When You Eventually Tear Off Two Layers
Every overlay roof eventually needs a full tear-off. When that day comes (17 to 22 years for most Florida overlays), the project is more expensive than a standard single-layer tear-off:
| Task | Single Layer Tear-Off | Double Layer Tear-Off |
|---|---|---|
| Tear-off labor | $1,000-2,500 | $1,800-4,000 |
| Disposal volume | 1 dumpster (typical) | 1.5-2 dumpsters |
| Disposal cost | $400-800 | $700-1,400 |
| Deck damage discovery | Moderate likelihood | High likelihood (hidden longer) |
| Deck repair cost | $0-4,000 | $1,500-8,000 |
| Project duration | 1-3 days | 2-4 days |
The double tear-off takes longer, costs more, generates more waste, and almost always reveals more deck damage (because the damage has been hidden under two layers for up to two decades). The person who pays for this is either you (if you still own the home) or the buyer (who will negotiate the price down accordingly).
How Overlay Affects Home Resale
If you are considering an overlay with the intention of selling the home in the near future, be aware that a two-layer roof is a standard finding in home inspections and can affect the sale:
- Buyer inspection findings. Home inspectors routinely check for multiple shingle layers and will flag a two-layer roof in their report. This gives buyers leverage to negotiate a price reduction.
- Buyer insurance challenges. The buyer's insurance company may refuse to insure the property or require the roof to be replaced before issuing a policy. This can delay or kill the sale.
- Appraiser adjustments. Appraisers may reduce the home's value if the roof is overlaid, particularly if comparable sales in the area have single-layer roofs.
- Perceived maintenance neglect. Buyers and their agents often view an overlay as a sign that the homeowner chose the cheapest option, which raises questions about how other maintenance items were handled.
The Better Alternative: Financing a Proper Tear-Off
If the only reason you are considering an overlay is budget, explore financing options before committing to an inferior installation:
- PACE financing (Property Assessed Clean Energy) is available in Pinellas County and covers roof replacements. Payments are made through your property tax bill over 10 to 20 years with no upfront cost.
- Home equity line of credit (HELOC) offers low interest rates secured by your home equity.
- Contractor financing programs are available through most major shingle manufacturers (GAF, CertainTeed, Owens Corning). These typically offer 12 to 18 months at 0% interest for qualified buyers.
- Insurance claim. If your roof needs replacement due to storm damage, your insurance policy should cover the tear-off and replacement. Do not overlay damage that insurance would pay to properly repair.
The difference between a $10,000 overlay and a $13,000 tear-off is $3,000. Financed over 5 years at 7%, that is approximately $60 per month. The insurance savings from wind mitigation credits alone may cover this payment, making the tear-off effectively free compared to the overlay. For a full cost breakdown, see our new roof cost guide.
Our Recommendation for Pinellas County Homeowners
After thousands of roof inspections and replacements across Pinellas County, our recommendation is clear: choose tear-off over overlay in nearly every situation. The upfront savings of $1,500 to $3,000 is not worth the hidden damage risk, reduced lifespan, voided warranties, insurance complications, wind vulnerability, and higher long-term costs.
The only scenario where we will perform an overlay is when all of the conditions listed in the “When Overlay Might Be Acceptable” section are met AND the homeowner understands and accepts the tradeoffs in writing. This represents fewer than 5% of our projects.
If you are facing a roof replacement decision and considering overlay to save money, call us for a free inspection. We will give you an honest assessment of both options, including the real long-term cost comparison for your specific home. Sometimes seeing the numbers side by side, tailored to your roof and your insurance situation, makes the decision obvious.
Related Roofing Resources
- Complete Roofing Guide for Pinellas County
- Roof Over vs. Tear-Off: The Complete Comparison
- Florida Building Code Roof Requirements
- Florida's 25% Roof Rule Explained
- New Roof Cost: What to Expect in 2026
Frequently Asked Questions
Can you put new shingles over old shingles in Florida?
Yes, the Florida Building Code allows a maximum of two layers of asphalt shingles. However, Florida's extreme heat, humidity, and hurricane exposure make overlay significantly riskier than in northern climates. The trapped moisture between layers accelerates degradation, the extra layer reduces wind uplift resistance, and the hidden deck cannot be inspected for damage. Most reputable Florida roofing contractors, including us, recommend tear-off over overlay in nearly all situations.
How much money does roofing over existing shingles save?
An overlay saves approximately $1,500 to $3,000 upfront compared to a full tear-off and replacement. This savings comes from eliminated tear-off labor, disposal costs, and slightly faster completion. However, the overlay's shorter lifespan (15 to 20% less than tear-off), reduced warranties, potential insurance premium increases, lost wind mitigation credits, and the eventual double-layer tear-off cost typically make overlay more expensive over the life of the roof. Our overlay vs. tear-off guide breaks down the full lifecycle math.
Does the Florida 25% rule apply to shingle overlays?
Yes. The 25% rule applies to all roof work including overlays (re-coverings). A full overlay exceeds 25% of the roof area, triggering the requirement for the entire roof to meet current Florida Building Code. In Pinellas County's high-wind zone, current code requires sealed roof deck underlayment (SWR), which cannot be installed without removing existing shingles. This means a code-compliant full overlay is technically impossible in most Pinellas County situations.
Will insurance cover a roof with two layers of shingles?
Insurance coverage for two-layer roofs varies by carrier, but the trend is toward stricter treatment. Some carriers will not write new policies on homes with two layers. Others insure the home but apply an actual cash value (ACV) endorsement on the roof instead of replacement cost value (RCV). During claims, two-layer roofs face additional scrutiny that can delay or reduce payouts. In Florida's already challenging insurance market, adding this complication to your policy is generally not worth the $1,500 to $3,000 upfront overlay savings.
When is a shingle overlay acceptable in Florida?
Overlay may be acceptable when all of the following conditions are met: single existing layer in good structural condition, no evidence of deck damage from attic inspection, genuine budget constraint that makes tear-off unaffordable, and building inspector approval for code compliance including the 25% rule. Even when all conditions are met, the overlay will have a shorter lifespan, reduced warranty, potential insurance complications, and will cost more when eventually torn off. We perform overlays on fewer than 5% of our projects.
How many layers of shingles are allowed in Florida?
The Florida Building Code allows a maximum of two layers of asphalt shingles. If your roof already has two layers, any future roofing work requires a complete tear-off down to the bare deck. Even with only one existing layer, the combination of Florida's climate, hurricane risk, and insurance landscape makes tear-off the better choice in nearly all situations. The marginal cost of tear-off is small compared to the long-term risks and costs of a two-layer roof.