Mold Remediation Sealers & Encapsulants

Mold Resistant Coatings: Application and Considerations

Purpose and Limitations:

• Fungicidal Protection: Mold resistant coatings are products applied to building materials to provide long-term fungicidal protection.  

• Topical Protection: These are topical protective coatings designed to prevent newly settled spores from propagating on coated surfaces.

• Pre-Cleaning Requirement: These products require a pre-cleaned, mold-free surface to be effective.  

• Re-Growth Potential: Mold will grow on these coatings if the surface is not properly cleaned or if it is subjected to renewed moisture.

• Vapor Barrier Effect: These coatings can act as a vapor barrier, potentially affecting the evaporation rate of wet materials.

• IH/CIE Approval: These products should only be applied to surfaces that have been visually approved by an IH/CIE, or if the IH/CIE requests application prior to inspection/testing.

Application Techniques:

• Airless Sprayer: Sealers should be applied using an airless sprayer fitted with a larger spray orifice.

  • Standard airless sprayers often have nozzles designed for light coatings, which can clog easily.

  • Larger orifices reduce clogging, minimize overspray, and require fewer passes for adequate coverage.

  • While a larger orifice will use more sealer, it will save time and improve the finish.

  • Larger, more expensive sprayers are not necessarily faster or a better investment.

• Proper Coating Thickness: Apply the coating thick enough to obscure the underlying wood material, but not so thick that it drips.

Application Surfaces:

• Suitable Surfaces: These products should be used on pre-cleaned and dried building materials, including:

  • Drywall.

  • Plywood.

  • Dimensional lumber (floor joists, roof rafters, wall studs).

Surfaces to Avoid Getting Sealer On:

• Protection: Mask off and protect:

  • Customer content.

  • Shower and tub enclosures.

  • Windows.

  • Concrete.

  • Fire sprinklers.

  • Finish flooring.

  • Cabinets & Countertops.

Concrete Considerations:

• Adhesion Issues: These products are not formulated to adhere to concrete or masonry. They will flake off over time.

• Inorganic Material: Concrete is an inorganic material with a low risk of mold growth.

• Surface Cleaning: Mold growth on concrete is typically due to surface dust/debris.

  • Clean debris/mold from the surface.

  • Apply a hydrogen peroxide (H2O2) product to lift remaining material.

  • Vacuum thoroughly.

Product Variations:

Clear Products:

• • Used when a tinted product is undesirable to the IH/CIE or occupant.

  • Leaves a shiny, wet-looking surface, which may be problematic in some applications.

White Tintable Products:

• • Typically a bright white product.

  • Can be tinted to match wood framing or other desired colors.  

  • Often requested in wood tones for attics, crawlspaces, and basement under structures.

  • Hidden interior wall surfaces are less likely to elicit color concerns from customers.

Black Products:

• • Generally used in interior spaces where visibility is unwanted, such as HVAC return boxes.

  • These interior return boxes should be at room temperature when applied.

HVAC Approved Products:

• • Fiberglass insulation in HVAC ductwork provides a porous environment for mold and particulate accumulation.  

  • Use products that create a thick, elastomeric hide to trap remaining particulate and prevent new penetration.

  • These products should be low- or non-VOC and capable of withstanding temperature extremes.

I. Equipment Required:

• Airless Paint Sprayer:

  • The requirement of a $800+ unit will apply the product no faster than the $300 unit.

  • Using (2) $300 units will allow entirely 2 employees to apply product faster & more economically than a single more expensive unit.

  • There's no connection between the sprayer horsepower rating & the viscosity (thickness) of the product it will apply.

    • So that's not 100% accurate, as yes, a higher HP unit will apply thicker sealers, but the consideration is they're pushing the product through smaller orifices. 

    • The area's we are applying these products to are largely hidden.

    • We are looking for material coverage, not a fine high quality finish.

• High-Flow Nozzle Requirement:

  • Always use a high-flow nozzle,  again the goal is coverage, not quality of the finish.

  • 517: The nozzle that comes with paint sprayers is generally for spraying trim, and will clog frequently.

  • 521-525: Is a nozzle that's recommended for application of heavy latex or smooth elastomeric sealers.

  • A decent hide, or thick coating is essential for the barrier effect to function effectively. 

II. Product Evaluation and Selection:

• Permeance Rating:

  • Sealers should be evaluated to ensure a permeance rating greater than 1.

  • This prevents the product from creating a vapor barrier on the sprayed surface.

• VOC Levels:

  • Where possible, use non-shellac products.

  • Shellac-based products have very high volatile organic compound (VOC) levels.

III. Project Preparation:

• Tape & mask off anything paint shouldn't be applied to.

  • This includes but is not limited to furniture, finish flooring, appliances, windows, bath tubs, & sprinkler heads. 

• Clean surfaces are a necessity, the products bonding is hampered by debris, especially oily residues.

• Dry surfaces are also required, wet materials will not allow the product to penetrate into the material as needed to bond.

• Material Moisture Content needs to be below 15%  prior to application.

• Temperatures of the air & materials need to be above 45 degrees F. 

  • However at temperatures below 70 degrees F. expect extremely slow dry times.

• The most ideal temperature is between 70 & 90 degrees F. 

• Strain the product if possible, this often requires carefully pouring the paint from one 5 gallon bucket into another clean 5 gallon bucket with a strainer pulled over the top, Then pull the strainer out slowly allowing the paint to filter through the bag. 

  • If you rush this, you will make a mess.

  • Use adequate means to catch spillage, a large cooking pan works fairly well.

  • Go slow, don't try to do all the paint at once, you'll have to squeeze the paint through the strainer more than likely.

• Purge the remaining water from the last cleaning into a small container with towels at the bottom to catch the burst of spray.

  • Turn the pressure down to its lowest pressure setting.

  • Turn the spray nozzle 180 degrees to purge into the small container as rapidly as possible.

IV. Personal Protective Equipment & Proper Ventilation

• • Proper ventilation is required during application of these products, and a NIOSH approved respirator using P100 canister filters must be worn.

  • An AFD should be setup under negative pressure, vented to the outside of the envelope of the property if natural ventilation isn't practical without mechanical assistance.

  • The AFD must be protected against overspray.

  • Proper protective equipment must also be worn, such as tyvek disposable coveralls, a painters head sock, and nitrile gloves. 

V. Application of Sealers:

• • Product should be applied over head first, working from the center of the room out where possible.

  • Product should be applied from ladders on the upper part of the walls, and from a normal standing position for the remaining section.

  • It should be thick enough that you can't see bare wood, also shouldn't be so heavy that it drips heavily.

  • Product should be applied to all all exposed wood.

  • Products should not be applied to cement or block materials as the product will not adhere & will flake off in a short amount of time. 

  • Despite best efforts, the paint sprayer will stop up while spraying.

    • Rotate the nozzle 180 degrees & trigger the sprayer to release the stoppage into a seperate paint can with some towels in the bottom to absorb the burst. Spraying back into the 5 gallon paint bucket the machine is connected to will basically recirculate the debris that stopped up the sprayer.

    • Rotate it back & continue spraying.

VI: Cleaning the Sprayer:

• Turn the power switch to the OFF position.

• Turn the pressure down to lowest setting. Trigger the spray gun to relieve line pressure from the machine.

• Turn the prime valve downward to the open position.

• Remove the filter assembly and assemble the spray gun without filter.

• Remove the guard and nozzle.

• Clean the filter, the guard and nozzle with water.

• Remove the siphon tube set from the paint and place in bucket of water. Use water for water for water based paints and sealers.

• If sprayer has a filter, unscrew the bowl, remove the filter assembly. Assemble the bowl without the filter. Clean the filter in water.

• Turn power ON and prime valve horizontal to the closed position.

• Hold the spray gun against the paint pail. Take the trigger safety OFF. Trigger the gun and increase pressure until flushing fluid appears.

• Move the airless gun to flushing pail. Hold spray gun against pail and trigger the gun to thoroughly flush system until water runs clear. Release the trigger and engage the trigger safety.

• Turn the prime valve to the down position (open) and allow flushing fluid to circulate for 1 to 2 minutes to clean drain tube.

• Raise siphon tube above flushing fluid and run sprayer for 15 to 30 seconds to drain fluid. Turn power switch to  OFF position.

• Install filter bowl and filter assembly. Hand tighten filter bowl. Install filter assembly into spray gun. Hand tighten gun handle.

• Wipe down sprayer, hose and spray gun with a rag soaked in water.

• Consideration: if the pump will the stored in freezing conditions: it's important to use a product such as pump armour, or if it's not available, windshield washer fluid will work temporarily.