Four chemistries do almost all the work in liquid-applied roof coatings: acrylic, silicone, polyurethane, and aluminum-pigmented asphalt. They differ on the specs that decide whether a coating survives on your roof: solids content, elongation, ponding-water resistance, reflectivity, warranty length, and installed cost per square foot. This is a side-by-side spec comparison of all four, plus the one distinction that clears up most of the confusion in this category.
Before the table, one correction that reframes the whole question. “Elastomeric” is not a separate coating type. It describes any coating that cures to an elastic film that stretches and recovers with the roof. Acrylic, silicone, and polyurethane are all elastomeric chemistries. Aluminum-pigmented asphalt is not. So a question like “elastomeric versus silicone” is really “acrylic versus silicone,” two members of the same family.
Roof coating types compared: the spec table
The table below compares the four coating families on the specifications that drive real-world performance. Numbers marked as ASTM minimums are the floor a product must clear to carry that standard, not a typical value. Cost ranges are installed price per square foot from published 2026 contractor and supplier data, and vary widely by mil thickness, prep, and region.
| Spec | Acrylic | Silicone | Polyurethane | Aluminum-asphalt |
|---|---|---|---|---|
| Base / chemistry | Water-based elastomeric | Moisture-cure elastomeric | Aromatic base, aliphatic top, elastomeric | Asphalt cutback with aluminum flake (not elastomeric) |
| Solids content | Moderate | High | Moderate to high | Low |
| Elongation (ASTM minimum) | ≥100% (D6083) | ≥100% (D6694) | ≥75% (D6947) | Not applicable |
| Tensile strength (ASTM minimum) | ≥200 psi | ≥150 psi | ≥1,500 psi | Not rated for tensile |
| Ponding water | Poor | Excellent | Moderate | Poor |
| Reflectivity (white, initial solar reflectance) | High (roughly 0.80 to 0.85) | High (CRRC-tested near 0.88) | High for white aliphatic | Moderate (roughly 0.55) |
| Foot traffic / abrasion | Low | Low (slippery when wet) | High | Low |
| Governing ASTM standard | D6083 | D6694 | D6947 | D2824 |
| Typical installed cost / sq ft | $0.50 to $3.00 | $1.50 to $7.00 | $3.00 to $6.00 | Low (see note below) |
| Best substrate | Sloped roofs that drain; metal; mod-bit in dry climates | Flat / low-slope with ponding; single-ply; existing silicone | High-traffic decks; wear areas | Asphalt / built-up; reflective refresh |
The four cost figures trace to published 2026 pricing: acrylic at roughly $0.50 to $3.00 per square foot installed, silicone at $1.50 to $4.50 with high-build 2026 quotes reaching about $7.00, and polyurethane at $3.00 to $6.00. Aluminum-pigmented coatings sit below these on material cost. A common 5-gallon fibered aluminum product listed near $114 covers roughly 1,000 square feet, which works out to about $0.11 per square foot in material (a Roofing Brief calculation from that listing), before labor.
Acrylic roof coating: cheapest, but drainage matters
Acrylic is a water-based elastomeric coating, the lowest first cost of the four, highly reflective in white, and easy to recoat. Under ASTM D6083 it must clear 200 psi tensile strength and 100% elongation. Its weakness is standing water: acrylic is breathable with a high perm rating, and most acrylic warranties exclude ponded areas because the film re-emulsifies under prolonged moisture.
Acrylic fits sloped and low-slope roofs that actually drain, in warmer and drier climates. It is a strong fit over metal and aged modified bitumen where the goal is reflectivity and UV protection rather than waterproofing a pond. Expect service of about 7 to 10 years before a recoat is due, depending on mil thickness and climate.
Silicone roof coating: the ponding-water specialist
Silicone is the coating built for standing water. Its moisture-cured film sits in a pond without softening, which is why silicone warranties typically cover ponding while acrylic warranties usually do not. It holds reflectivity well, with white silicone tested by the Cool Roof Rating Council near 0.88 initial solar reflectance, and it resists UV and chalking better than any of the four.
Under ASTM D6694 silicone must reach 150 psi tensile and 100% elongation. On many product lines, warranty length tracks mil thickness directly: roughly 20 mils for a 10-year warranty, 25 mils for 15 years, and 30 mils for 20 years. Two trade-offs to plan for: silicone is slippery when wet, and it bonds poorly to other coatings and to cured silicone, so recoating usually means silicone over silicone only.
Polyurethane roof coating: for foot traffic and abrasion
Polyurethane wins on toughness. Under ASTM D6947 it must clear 1,500 psi tensile strength, an order of magnitude above acrylic or silicone, which is why it is the choice for roofs that take regular foot traffic, carts, or mechanical wear. Systems are usually built as two layers: an aromatic base coat for strength and an aliphatic top coat for UV and color stability.
The aromatic base chalks and discolors under sun, so it is never left exposed; the aliphatic top does the weathering. Polyurethane handles ponding moderately, better than acrylic but below silicone. It carries the highest installed cost of the four, roughly $3.00 to $6.00 per square foot, and aliphatic top coats can cost close to twice the aromatic material underneath.
Aluminum-pigmented asphalt coating: the reflective refresh
Aluminum coating is the outlier: an asphalt cutback or emulsion carrying aluminum flake that floats to the surface as it cures, leaving a reflective silver film. It is governed by ASTM D2824, which rates it on luminous reflectance rather than elongation, because it is not an elastomeric membrane. It is the least expensive option on material cost and the simplest to brush or spray on aged asphalt and built-up roofs.
The trade-off is that its roughly 0.55 reflectance sits well below a white elastomeric coating, and aluminum-coated roofs tend to run hotter than elastomeric-coated ones because the metal retains heat. It does not bridge or waterproof like the elastomeric three. Treat it as a reflective, UV-protective refresh for asphalt surfaces, not a waterproofing membrane.
How to choose a roof coating
Match the coating to the roof’s biggest problem, not to a brand. The order below reflects how the decision actually narrows on a real job.
- Check for ponding. If water stands on the roof for more than 48 hours after rain, silicone is the default. Acrylic and aluminum will fail early under standing water.
- Check the traffic. If people, carts, or equipment cross the roof regularly, polyurethane’s abrasion resistance justifies its higher cost. Silicone is slippery and acrylic is soft by comparison.
- Check the climate and budget. On a well-draining roof in a warm, dry region where reflectivity and low cost matter most, acrylic delivers the most coverage per dollar.
- Check the existing surface. Aged asphalt or built-up roofs that only need a reflective, UV-protective refresh are the classic case for aluminum coating. Existing silicone must be recoated with silicone.
- Confirm compatibility and mils. Read the manufacturer data sheet for adhesion to your substrate and the mil thickness required for the warranty term you want. Warranty length usually tracks mil build, not marketing.
How these figures were sourced
The Roofing Brief did not independently lab-test these coatings. The elongation, tensile, and standard designations are the published ASTM minimums for each chemistry (D6083 acrylic, D6694 silicone, D6947 polyurethane, D2824 aluminum-asphalt). Reflectance figures come from Cool Roof Rating Council listings and manufacturer data. Cost ranges are compiled from 2026 contractor and supplier pricing and move with mil build, prep, and region. Any single product can beat or miss these ranges, so verify the specific number on the product data sheet before you buy.
For single-product picks within each family, see our rankings of the best silicone roof coatings, best elastomeric roof coatings, and best aluminum roof coatings. For the two closest chemistries head to head, see silicone vs acrylic roof coating. To decide whether to coat at all, read roof coating vs replacement, and for measured reflectance values by surface, see our roofing solar reflectance and SRI reference.
Reviewed by The Roofing Brief Team. Last reviewed August 2026.