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ARMORTHANE PROTECTING YOUR WORLD

PROTECTING YOUR WORLD

ARMORTHANE PROTECTING YOUR WORLD

Roof Restoration:
Restore, Recoat
or Replace?

How a commercial roof restoration works, how to tell if your roof qualifies, what each roof type needs, and what restoring costs per year of service compared with tearing off.
Restoration quotes

Is your roof worth saving? Find out before you tear off.

Tell us what the roof is made of, how old it is and what you are seeing. We will connect you with a certified ArmorThane applicator who surveys for wet insulation and quotes a written restoration scope, or tells you plainly when it is time to replace.

  • Roof type: metal, single-ply, BUR, mod bit or foam
  • Approximate size in square feet
  • Age and any leak history
  • Recent moisture scan or core results, if you have them
Rather talk now? Call (417) 831-5090
Step 1 of 3
20–25%
Saturated roof area where replacement usually wins
Roofing Contractor
10–20 yr
Typical warranty per coating cycle, set by dry mils
Manufacturer warranty tiers
50–70%
Typical savings over tear-off and replacement
American WeatherStar
7–10 days
To restore an average 20,000 sq ft roof
Weather permitting

Roof restoration is what you do with a roof that leaks or looks tired but still has a sound deck and mostly dry insulation underneath. Instead of hauling it to the landfill, you clean it, cut out the bad spots, reinforce the seams and spray a new fluid-applied membrane over the whole thing. Done at the right time, it buys years of service for far less than a new roof.

Quick answer

Roof restoration means cleaning, repairing and recoating an existing low-slope or metal roof with a seamless elastomeric membrane instead of tearing it off. It makes sense when the structure is sound and well under 20–25% of the insulation is wet. Applied at the warranted thickness, a restoration typically adds 10 to 20 years and can be recoated again later.

What's in this guide
  1. 1Does your roof qualify?
  2. 2How it is done
  3. 3Life-cycle cost planner
  4. 4By roof type
  5. 5Warranties and recoats
  6. 6Questions
Screening

Is your roof a candidate for roof restoration?

Age alone does not decide it. A 30 year old metal roof can be a great candidate, and a 12 year old single-ply roof can be soaked through. What decides it is what is under the membrane, and you only learn that with a moisture survey and a few cores.

What the survey findsRankWhat it usually means
Dry insulation, a few open seams or worn coatingRestoreThe ideal candidate. Repair the details and coat.
Wet spots under about 10% of the areaRestore after repairsCut out wet insulation and membrane, patch flush, then coat the whole roof.
Metal panels with surface rust, loose fastenersRestore after repairsWire brush and prime the rust, replace or oversize fasteners, seal laps.
Wet area creeping toward 20%BorderlineTake more cores and price both ways. Repairs start to cost as much as a reroof.
20–25% or more saturatedReplaceToo much wet material to trap under a new coating. Tear off and reroof.
Rusted-through or soft deck, sagging structureReplaceA coating is not structural. Fix the deck first, which usually means tear-off.
General screening guide. Saturation threshold from Roofing Contractor; your roof needs its own survey. Tap a column heading to sort.
Nondestructive

Infrared scan

Wet insulation holds heat after sunset and shows up warm on a thermal camera. ASTM C1153 covers the method. Fast for big roofs, but it needs the right weather.

Nondestructive

Capacitance or impedance meter

A meter rolled across the roof in a grid reads moisture under the membrane. Works in daylight and on roofs where infrared struggles.

Destructive

Core cuts

A small core confirms what the scans suggest: how many layers, what insulation and how wet. Every core gets patched the same day.

Before you commit

Adhesion test patch

A small patch of the planned coating, cured and pulled, proves it will stick to this roof. Cheap insurance on aged single-ply and asphalt roofs.

Process

How a roof restoration is done, step by step

Most of the work happens before the coating rig is even turned on. A crew that shows up and starts spraying the same morning is skipping something.

  1. Survey and map the roof

    Moisture scan, cores, photos of every drain, curb and penetration. The map becomes the repair scope and the record for the warranty.

  2. Cut out what is wet

    Wet insulation and the membrane over it come out and get replaced flush with matching material. Coating over wet insulation traps the water and it keeps rotting the deck.

  3. Clean the surface

    Pressure wash off dirt, chalk, algae and loose granules, then let it dry. Single-ply roofs often need a dedicated cleaner, and some asphalt roofs need a bleed-blocking primer.

  4. Reinforce the weak points

    Seams, laps, fasteners, flashings and penetrations get mastic or coating with polyester reinforcing fabric. This is where leaks live, so this is where the extra material goes.

  5. Spray the base coat

    The base coat goes on at a measured wet thickness and is checked with a gauge as the crew works. Ponding areas and drains get extra attention.

  6. Spray the topcoat and document it

    A UV-stable, usually white, topcoat brings the system to its total dry mils. Thickness readings and photos go into the closeout package that backs the warranty.

Fix the drainage while you are up thereA restoration is the cheapest time to add a cricket, a drain or a scupper. Coatings that tolerate ponding still last longer on a roof that drains. If water sits on your roof two days after rain, read our guide to flat roof repair before you sign a coating contract.
Planner

What restoring costs per year of roof

Comparing a restoration bid with a replacement bid on the day you sign is only half the picture. The useful number is cost per year of dry roof over the time you plan to own the building, including the recoats a coated roof will need. Plug in your own quotes; the defaults are midpoints of published ranges.

Life-cycle math

Restoration vs. replacement over your hold period

Restoration = area × restoration price, plus the wet area × replacement price for cut-outs. Recoats repeat every warranty term inside your hold period, priced the same as the first coat to stay conservative. Replacement repeats every roof-life term. Default prices: restoration $4–$7 and replacement from $10 per sq ft (Roofing Contractor).

—
Restoration today, with cut-outs
—
Restore path, cost per year
—
Replace path, cost per year
—
Difference over your hold period

Need a price to plug in? The roof coating cost guide breaks prices down by coating and roof type.

Roof types

What each roof needs before the coating

The coating is close to the same job on every roof. The prep is not, and the prep is what fails when a restoration fails.

Metal

Rust, fasteners and laps

Treat rust down to sound metal and prime it. Replace backed-out screws with oversized ones, then seal every lap and fastener row with fabric-reinforced coating. Our metal roof repair guide goes deeper.

Single-ply

TPO, EPDM and PVC

Check for shrinkage pulling at the edges and curbs, and repair it first. These membranes are slick and chemically fussy, so use the cleaner and primer the coating maker lists and always run an adhesion test.

Asphalt

Built-up and modified bitumen

Cut and patch blisters, sweep off loose gravel or granules, and expect asphalt to bleed through some white coatings. A bleed-blocking primer or a compatible base coat solves it.

Spray foam

SPF roofs

Sand back any UV-damaged foam, fill hail dings and recoat on schedule. A worn foam roof can also take fresh foam, such as ArmorFoam Roof 200, to rebuild slope and R-value before the new topcoat.

Shingle roofs are a different animalOn a steep-slope shingle roof, "restoration" usually means a rejuvenating treatment or a specialty coating, not a full membrane. It can buy time on shingles that still hold their granules. It will not fix curled, cracked or missing shingles. See our shingle roof coating guide for what works.
Warranties

Mils, warranties and the next recoat

Coating warranties are sold by thickness. Ten, fifteen and twenty year terms each call for more dry mils, and one manufacturer's metal-roof spec runs about 34 dry mils of silicone for 20 years. Ask every bidder which tier their price buys and how they will prove the thickness.

Cool and cheap

Acrylic

Bright white and easy to recoat, but it does not like standing water. Best on roofs that drain well. Compare it with others in our cool roof coating guide.

Ponding tolerant

Silicone

Handles ponding and UV well and goes on in one heavy coat. Future recoats generally need silicone again. Details in our silicone roof coating guide.

Tough

Urethane

Strong and impact resistant, often used as a base under an aliphatic topcoat on foam and traffic areas.

Fastest

Spray polyurea

100% solids, cures in seconds and builds thick film in one visit, which keeps roofs open for business. More in our polyurea roof coating overview.

The big advantage of a restored roof is that the next cycle is smaller. At the end of the term, a crew cleans, repairs the details and adds a new topcoat. The original roof stays in place, and so does the money you would have spent tearing it off. Commercial owners should also ask their tax advisor about Section 179: the 2017 tax law added improvements to nonresidential roofs to the property that can be expensed.

Survey first, then spray

An honest restore-or-replace call, in writing.

A certified ArmorThane applicator can scan your roof, core the questionable areas and quote a restoration at a stated mil thickness, or tell you when a reroof is the better spend.

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FAQ

Roof restoration questions

What is roof restoration?

It is renewing an existing roof in place: surveying for moisture, replacing wet sections, cleaning, reinforcing seams and penetrations, then applying a seamless elastomeric coating system. The old roof stays on, so there is no tear-off, and the new membrane carries its own warranty.

How long does a roof restoration last?

Most coating systems are warranted for 10, 15 or 20 years, with the term set by the dry film thickness applied. At the end of that term the roof can usually be cleaned, repaired and recoated again rather than replaced.

Is restoring a roof cheaper than replacing it?

Usually, yes. Published figures put restoration around $4 to $7 per sq ft against $10 and up for replacement, with savings often quoted at 50 to 70%. The gap shrinks as the amount of wet insulation that must be cut out grows.

When is a roof too far gone to restore?

When roughly 20 to 25% or more of the roof is saturated, when the deck is rusted through or soft, or when the structure is failing. At that point a coating would trap water over a bad base, and replacement is the right call.

Can a roof be restored more than once?

Yes. That is the main appeal. At the end of the warranty term the surface is cleaned, details are repaired, and a new topcoat is applied, which typically renews the warranty without tearing anything off.

Is a commercial roof restoration tax deductible?

The 2017 Tax Cuts and Jobs Act added improvements to nonresidential roofs to the property eligible for Section 179 expensing. Whether your project qualifies, and how much you can deduct this year, is a question for your tax advisor.

AT
Written by the ArmorThane technical team. We have manufactured polyurea, polyurethane and polyaspartic coatings, spray foam and plural component spray equipment in Springfield, Missouri since 1989. Prices and thresholds here are typical; a moisture survey of your own roof and the coating maker's warranty spec govern the real scope.

Sources

  1. Roofing Contractor, Restore or Replace? roofingcontractor.com/articles/102096-restore-or-replace
  2. American WeatherStar, Roof Restoration guide. americanweatherstar.com/insights/roof-restoration
  3. ASTM International, C1153 Standard Practice for Location of Wet Insulation in Roofing Systems Using Infrared Imaging. astm.org/Standards/C1153.htm
  4. National Roofing Contractors Association, IRS releases fact sheet regarding new expensing rules. nrca.net/RoofingNews

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Restore it right, recoat it later.

Building owners get a certified ArmorThane applicator who surveys first, repairs what is wet and sprays to a written mil spec. Contractors can add roof restoration with our coatings, foam, spray rigs and training, with no franchise fee and no royalties.

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