How to Read a Roof Coating Data Sheet

Every commercial roof coating ships with a technical data sheet (TDS) — a two-to-four page document with roughly 30 numeric properties. Contractors glance at three of them. Facility managers who learn to read all 30 stop getting bait-and-switched. This guide decodes the TDS one field at a time, in plain English, from the owner's perspective.

The Seven Numbers That Actually Matter

Before decoding the whole sheet, here are the seven properties you should always check on any TDS. If any of these are missing or vague, treat it as a red flag.

1. Solids Content (by volume)

What percentage of the can becomes the final dry film. A 60% solids acrylic means 40% of what you paid for evaporates. High-solids silicones run 90-100%. This number drives the true material cost per dry mil: a $30/gal product at 50% solids costs the same per square foot as a $55/gal product at 90% solids.

2. Tensile Strength (psi, ASTM D-412)

How much pulling force the cured coating can take before tearing. Acrylics typically hit 300-500 psi, silicones 250-400, polyurethanes 1000-2000. Higher is better for foot-traffic and impact resistance. For warehouse roofs with normal maintenance, 300+ is adequate.

3. Elongation at Break (%, ASTM D-412)

How far the coating stretches before it snaps. Critical for thermal cycling — a roof that swings from 40°F at night to 160°F in afternoon sun expands and contracts, and the coating has to stretch with it. Target 200%+ elongation for commercial use. Below 100% is a red flag for anything but mild climates.

4. Solar Reflectance (initial + 3-year aged)

Both numbers should appear. Initial reflectance on day one is marketing; the 3-year aged value is what the coating actually delivers after soiling. The gap between initial and aged tells you how dirt-resistant the formula is. White acrylics usually drop 10-15 points; white silicones hold their reflectance better. For Title 24 compliance the 3-year aged SR must be ≥ 0.63.

5. Solar Reflectance Index (SRI)

A combined metric that rolls reflectance and thermal emittance into one number, normalized so a standard black surface = 0 and a standard white surface = 100. LEED and Title 24 both use SRI thresholds. For low-slope commercial roofs, SRI ≥ 75 is the standard target.

6. Application Thickness (dry mils vs wet mils)

The number that gets manipulated most. A TDS might list "20 dry mils" as the minimum — meaning the final cured coating must be 20 mils thick. That requires more wet mils at application because the solvent/water evaporates. With a 50% solids product, 20 dry mils requires 40 wet mils. Contractors who quote gallon counts based on wet mils without adjusting for solids content will leave you with half the coating you paid for.

7. Warranty (Product vs System)

The trickiest line on the sheet. A "20-year warranty" usually means product warranty — the manufacturer will replace failed material. A "system warranty" covers labor and material both, but requires factory-certified applicators and professional inspection. Ask explicitly which one you're getting. Most owners who think they have a 20-year warranty actually have a 20-year product warranty with 2-year labor coverage.

The Fields You Can Usually Skim

The remaining TDS fields matter for contractors and chemists but rarely affect owner decisions. You should recognize them but don't need to evaluate them:

Viscosity (cps): How thick the liquid is. Affects spray equipment selection.
Shore A hardness: Surface firmness. Relevant for specifying foot traffic tolerance on polyurethane systems.
Permeability (perms): Moisture vapor transmission. Important for specific substrate compatibility decisions contractors make.
Shelf life and pot life: Storage and mixing timelines. Contractor logistics.
Flash point: Fire hazard rating for solvent-based products. Relevant for storage, not selection.

VOC Content

Volatile organic compound limits are driven by EPA and state air-quality rules. California has the strictest limits (50 g/L for most roof coating categories via CARB); most other states follow EPA national limits. For facility managers this is primarily a compliance check, not a performance metric — verify the product is legal in your jurisdiction, then move on. Water-based acrylics are almost always sub-50 g/L. Solvent-based asphalt and some polyurethanes can run 250+ g/L and are banned in California without a variance.

ASTM Standards Referenced on the Sheet

You'll see ASTM numbers cited next to most properties. You don't need to read the standards themselves — but you should recognize them because their presence (or absence) signals whether the manufacturer actually tested to spec:

ASTM D-412: Tensile strength and elongation test method. Should always appear next to those properties.
ASTM D-6083: Liquid-applied acrylic roof coating spec. If you're buying acrylic, the product should meet D-6083.
ASTM D-6694: Liquid-applied silicone roof coating spec. Silicone products should comply.
ASTM D-6947: Liquid-applied urethane roof coating spec. Polyurethane compliance reference.
ASTM C-1549 / E-903: Solar reflectance measurement methods (backing the CRRC values).
ASTM E-408 / C-1371: Thermal emittance measurement methods.

If you want to go deeper on the underlying test methods, the full ASTM standards are referenced on the US Made Supply commercial roofing reference pages, which cross-link each standard to the properties it governs.

How a Bait-and-Switch Actually Works

Understanding the TDS lets you spot the three classic contractor switches:

Solids downgrade. Bid specifies a 90% solids silicone at $55/gal. Contractor shows up with a 70% solids product at $40/gal. Same coverage in wet mils, 30% less dry film. Looks identical on day one, fails in year 7 instead of year 20.
Initial-vs-aged reflectance. Bid references "85% solar reflectance." Contractor delivers a product with 85% initial but 65% aged. Building fails Title 24 inspection at the certificate of occupancy stage.
Product-only warranty sold as system warranty. Bid promises "20-year warranty." Contractor delivers a product with a 20-year material warranty and a 2-year labor warranty. First blister at year 3 is on you.

Every one of these is preventable by writing the specific property values (not just product names) into your contract. Cite the TDS fields, cite the dry mil minimum, cite the aged SR number, cite the warranty type. Then require the applicator to submit the TDS with the bid.

Where to Find Real Data Sheets

Every manufacturer publishes TDS documents on their product pages. For a quick way to compare multiple products side-by-side, commercial roof coating product pages at US Made Supply link to the manufacturer TDS for each SKU and list the key properties (solids, tensile, elongation, SR, SRI) inline so you don't have to download PDFs for every comparison.

Next Steps

Once you can read a TDS, the next step is matching the product to your building. Our free satellite roof analysis pulls the physical characteristics (roof area, pitch, exposure) and our facility-type coating comparison narrows down the chemistry. The TDS is the final checkpoint before you sign.