1. How Much Roof Coating Do You Need?
In order to estimate how much roof coating you’ll need, you first have to estimate the total square footage of your roof’ssurface. Measure the length and width of each plane on the roof, including dormers. Then, multiply length x width toget the square footage of each plane. Add the square footage of each of the planes together to derive the total squarefootage of your roof.
2. Weather Conditions
Before application, KEEP THE COATING FROM FREEZING. Apply only at temperatures above 50°F (10°C). Do notapply late in the afternoon or early evening when a heavy dew could develop on the coating surface before it driesthoroughly. A heavy rainstorm, such as those common in tropical climates, could wash the coating off during the firstfew hours after application, if it has not completely dried.
IMPORTANT: Do not allow an application to become subject to rain, condensation, or moisture within the first 72 hours after application. These conditions could cause loss of adhesion, peeling or flaking. Do not apply the coating over a wet or moist surface – the surface should be completely dry prior to application to ensure proper adhesion.
3. Surface Preparation
Application:
Keep products away from heat, sparks and flames. Do not allow the use of spark producing equipment duringapplication and until vapors is gone. Post “No Smoking” signs.
The overspray and/or solvents from spraying liquid-applied roofing materials can carry considerable distances and care should be taken to do the following:
A. Post warning signs a minimum of 100 feet from the work area.
B. Close air intakes into building and/or air conditioner intakes.
C. Set up windbreaks when needed.
D. Minimize or exclude all personnel not directly involved with the coating application.
E. Have CO2 or other dry chemical fire extinguishers available at the jobsite.
F. Provide adequate ventilation.
Low areas that hold excessive ponding water must be brought into conformance by applying liquid roof patch to level the sloped area or by installing additional drains. Protect plants, vegetation and animals which might be affected by the coatings. Use drop cloths or masking as required.
Cleaning Surface:
Remove all unnecessary and non-functional equipment and debris from the roof. Remove dirt and foreign material detrimental to adhesion or application of fluid-applied roofing by thoroughly cleaning all roof surfaces with a high-pressure (2,500 – 3,000 psi) wash. Surfaces contaminated with oil, grease, animal fats, etc. must be removed using tri-sodium phosphate and water, or other solutions as required by job conditions and as permitted by local, state, and federal regulations. Remove all cleaning solutions with plenty of fresh water. Note: If algae is present on the surface, the cleaning must include bleach in the washing of the substrate. Membranes with seam and flashing failure shall must be repaired then detailed with flashing tape.
Detailing Roof Surface:
Detail repaired areas with two pre-coats of elastomeric base coat at the rate of 1 gallon per 100 square feet (100 sq. ft./gal) minimum. Elastomeric base coat shall extend a minimum of 2 inches beyond the edges of the repair. Round projections, machine legs, sign posts, guide wire straps, inside and outside corners, etc. should be flashed using a compatible sealant. Seal watertight gutters, parapet walls and caps. Repair any damaged metal. Caulk and seal watertight all screws, seams, skylights, joints, pipes, voids, protrusions and any areas where water could enter through the roof. Clean and seal all drains watertight. Allow roof and other prepared surfaces to dry completely before proceeding with priming and/ or coating application. Note: Thickness values of cured film are averages and can vary due to finish of surface. High sloped roofs may require multiple coats to achieve specified dry film thickness.
Protection:
After completion of application, do not allow traffic on coated surfaces for a period of at least 48 hours at 75°F and 50% R.H., or until completely cured.
4. Roof Substrate Applications
All roof surfaces must be properly cleaned before any application of coating. If it is a new roof, sweep or use a high-pressure blower prior to washing. All repairs must be made before cleaning is done to insure no interior water damage.Power wash the roof’s surface with clear water.
Apply SolarEx coatings to the substrate at the rate of 1.5 gal/100 sq. ft. (1.5 gallon per square) @ 16 wet mils each coat (primer, base coat and top coat), to yield a total of 45 mils coverage. Sloped or rough surfaces will require an extra thickness of SolarEx coating to obtain proper coverage and to produce a smooth surface. Actual required application rate will depend on system specified and length of warranty. For low areas that hold excessive ponding water, apply a liquid roof patch to level the sloped area prior to coating.
5. Coverage – Wet Mils to Dry Mils (Sq. Ft Per Gallon)
To calculate the mil Dry Film Thickness (DFT), take the solids content (by volume) of the coating and multiple it by thewet mil thickness that the coating was applied. For example, if the coating is 50% solids by volume and it is applied atcoverage rate of 16 mil wet mils, then 50% of the 16 wet mils (solvents/water) will evaporate. The other 50% of thecoating will remain on the substrate as the DFT coating.
Calculations for Dry Mils Coverage (Sq. Ft Per Gallon)
*100% solids x 16 mils (wet) = 16 dry mils
-applied at 1 gal/100 sq. ft. (x 100) = 1600 sq. ft. coverage per gallon
*75% solids x 16 mils (wet) = 12 dry mils
-applied at 1 gal/100 sq. ft. (x 100) = 1200 sq. ft. coverage per gallon
*50% solids x 16 mils (wet) = 8 dry mils
-applied at 1 gal/100 sq. ft. (x 100) = 750 sq. ft. coverage per gallon
6. Coverage – Squares
Roofing square is the most used measurement unit used by roofing contractors, as well as contractors from manyother trades. It greatly simplifies communication between architects, contractors, roofing manufacturers, suppliers andeven clients. It’s much easier to say 25 squares than 2507 square feet, and there is less information lost in translation.
What is a roofing square? Essentially it is 100 square feet or a 10×10′ block. Because roofs, siding and other projectsare large, using a square as measurement keeps it from getting complicated. Taken for the Coverage – Wet Mils to DryMils (Sq. Ft Per Gallon) example in section 5:
*100% solids x 16 mils (wet mils) = 16 dry mils
-applied at 1 gal/100 sq. ft. (x 100) = 1600 sq. ft. coverage per gallon
-÷ 100 = 16 squares
*75% solids x 16 mils (wet mils) = 12 dry mils
-applied at 1 gal/100 sq. ft. (x 100) = 1200 sq. ft. coverage per gallon
-÷ 100 = 12 squares
*50% solids x 16 mils (wet mils) = 8 dry mils
-applied at 1 gal/100 sq. ft. (x 100) = 800 sq. ft. coverage per gallon
-÷ 100 = 8 squares
7. Typical SolarEx Application Coverage Guidelines
On smooth flat roof surfaces apply SolarEx coatings to the substrate at 1.5 gal/100 sq. ft. (1.5 gallon per square)at the rate of @ 16 mils each coat (primer, base coat and top coat), to yield a total of 53 mils coverage. Sloped orrough surfaces will require an extra thickness of SolarEx coating to obtain proper coverage and to produce asmooth surface. Actual required application rate will depend on system specified and length of warranty.
Cure time is estimated at 75°F (24°C) and 50% relative humidity, to allow 10-12 hours for the coating to fully cure.
Note
Surfaces that are porous may absorb some of the material thus, requiring an increase of wet mils in order to attain thedesirable dry mil thickness.
Caution
Do Not apply coating if surface temperature is 55°F or lower.
Do Not apply coating if the temperature is expected to drop below 35°F within a 48-hour period.
Do Not apply coating if rain is forecasted within a 48-hour period.
8. Project Conditions
A. The number of recommended gallons per 100 square feet may need to increase due to uneven application, roughsurface texture, wind conditions while spraying or other variables.
B. Comply with insurance underwriter’s requirements applicable for products of this section.
C. Do not install insulation on roof deck when water of any type is present. Do not apply roofing materials whensubstrate is damp or wet.
D. Do not apply materials unless surface to receive roofing system is clean, dry and prepared as specified.
E. Install all material in strict accordance with all published product data sheet and safety, weather, or applicableregulations of the manufacturer and/or local, state, and/or federal agencies which have jurisdiction.
F. The entire system shall be fully adhered to the surface on which it is applied. Voids left under the system by creatingbridges are not acceptable.
G. Do not proceed with the application of coating when temperature is less than 50°F. No coating system shall beapplied if weather will not permit it to dry prior to exposure to precipitation or freezing.
H. Heavy puddles of coating on the roof are not acceptable.
I. Product Technical Data Sheet instructions for use of all roofing materials and application equipment should be readand followed at all times.
J. As a general principle, to prevent the ponding of water, apply a liquid roof patch to level the sloped area or installadditional drainage systems as necessary.
9. Cleaning & Protection
A. Do not leave installed insulation exposed to weather. Cover and waterproof with completed roof systemimmediately after installation.
B. Temporarily seal exposed insulation edges at the end of each day.
C. Remove and replace installed insulation that has become wet or damaged with new insulation.
D. Protect installed insulation and roof.