Fire Damage Restoration: Choosing a Sealer

fire damage restoration sealer

The devastation of a fire can wreak havoc on a building and significant work will be required to restore it. Fire damage restoration works to reverse the destruction of a fire and return structures to their former states — and implementing coatings to walls and surfaces is a crucial part of that process.

Smoke damage sealers are a special kind of coating that adhere to damaged surfaces, block stains and prevent the detrimental odors from lingering smoke after a fire, protecting a building from the after effects of the fire.

You might not realize how important sealers are to successful fire restoration, but smoke sealing after a fire is an integral part of preparing the site for reuse, covering damage after cleaning and contaminant removal, and ensuring deodorization and the absence of additional harm. From picking the right primer and differentiating between sealers to the process of painting over fire-damaged walls, here is everything you need to know about smoke odor sealers.

When a Sealer Should Be Used

How useful can sealers be and when is the right time for fire restoration professionals to use them?

With more and more restoration companies popping up over the years to remediate damage from fire and other disasters, smoke sealers are often used in a variety of ways.

Smoke sealers are intended for use only after all cleaning and contamination removal has been completed to the satisfaction of all involved parties. They are not intended to cover up poor restoration work. The point at which a sealer should be applied – and even if one should be applied at all – will depend on the individual scenario, with factors like the type of fire that occurred and the extent of the damage affecting the choice.

In 2016, fire departments across America responded to approximately 1,342,000 fires, 74 percent of which were structural fires. With home structure fires occurring, on average, every 90 seconds and other structure fires occurring every 66 seconds, the scale of national fire damage is significant, and the need for restoration is crucial.

fire stat

Because fires occur for different reasons, the type of chemical and physical damage differs from structure to structure:

  • Cooking equipment causes approximately 47 percent of home fires
  • Heating equipment is responsible for 15 percent
  • Electrical equipment accounts for 9 percent
  • Smoking materials account for 5 percent

In addition to the presence of chemicals responsible for beginning the fire, the fire itself produces a variety of toxins that contaminate the building – these may also affect the choice on when and if to use a sealer.

Why Use Smoke Sealant at All?

The heat, flames and uncontrolled combustion of fires lead to the production of a mix of harmful chemicals, including gases, liquids, aerosols and partially-oxidized particles, some of which adhere to surfaces and corrode materials. Even after the fire is extinguished, toxic odors and volatile emissions can continue to damage the structure and make the area hazardous.

In combination with effective cleaning and contaminant removal practices, sealers can be an effective way to prevent the returning of smoke odors or stains and serving as a primer by adhering to difficult surfaces so that a final paint coat can be applied.

Remember that sealers are not a cleaning agent in themselves, and they should never be used in an attempt to cover odors or contaminants that should have been treated and removed. Sealers serve to bind surfaces, block pores and prevent the return of odors, stains and additional damage. They should only be used after proper, thorough cleanup and contaminant removal.

Sealer vs. Encapsulant: What Is the Difference?

Even in the professional restoration industry, people sometimes use the terms “sealer and “encapsulant” interchangeably, but they should not. The two types of coatings have very different purposes, and confusing their uses could lead to problems.

What is the difference? Encapsulation describes the process of enclosing or repressing something, so it makes sense as a term used to designate wall coatings and primers. Technically, sealers encapsulate porous surfaces, stopping odors and damage from returning. Encapsulants perform a similar task by being applied to walls to permanently manage and abate the presence of asbestos and lead-based paint in older buildings.

While on the surface, these two types of coating appear to serve the same purpose by preventing further damage through the release of odors and chemicals, they are fundamentally different in terms of process, which is where the danger lies in confusing them.

  • Encapsulant: A coating that is used to manage exposure to the underlying materials or contaminants. This term is commonly used when referring to managing exposure to asbestos or lead-based paint.
  • Sealer: A coating that is applied after all contaminants have been removed ad surfaces thoroughly cleaned in order to prevent the reoccurrence of damage such as stains or odor.

sealer vs encapsulant

You can only apply sealers to surfaces after a thorough cleaning and removal of contaminants, and they bar the return of damage. Encapsulants, on the other hand, are put directly over the undesirable substance, covering it rather than removing it.

During restoration, contaminant removal always comes before coating with a sealer, so encapsulants and sealers should not be confused or used interchangeably in the fire damage restoration industry.

Considerations When Choosing a Sealer for Fire Damage Restoration

Now that you are familiar with the basic purpose and usage of sealers, how can you determine the best primer for smoke damage?

Each kind of sealer comes with its own specific attributes and limitations, so it is important to select the type that best meets your needs based on individual project. Here are some questions to consider when evaluating the features, functions and benefits of a sealer for restoring.

Does It Stick?

The first step to evaluating the benefits of a particular sealer is observing whether it adequately adheres to the surface you coat. If the sealer does not stick well, it is not particularly suited to the surface, and it will not make a good choice for aiding restoration.

Will It Suppress Lingering Fire-Related Odors?

Half of a sealer’s job is to hinder the return of unpleasant or harmful odors from smoke and fire-related chemicals. When selecting the right sealer, make sure it is effective in suppressing existing odors and inhibiting those scents from returning through the pores of the surface. If not, the coating will be just for show — and that is not useful to your purpose.

suppress odors

Can It Seal Stains and Residues Reliably?

The other half of a sealer’s functionality rests in blocking the spread of stains and residue. The goal is to keep the decontaminated surface clean and presentable, restoring it to its former state, so the risk of bleeding smoke stains should be reduced as much as possible. An effective sealer must prevent unsightly and unwanted stains from spreading if there is potential for this to occur.

Will Water Vapor Be Able to Breathe?

If the structure you restore experiences internal moisture of any kind in keeping with its function, make sure the sealer you select will allow for some release of water vapor. If you use an incompatible coating in an area that will see moisture buildup, it could lead to other problems with your restoration job in the future, including water damage and warping of the walls.

Will the Use of the Sealer Simplify Cleanup Complications?

During your restorative process, consider where the use of sealer fits in. If you have been able to clean, decontaminate and deodorize without many remaining issues, sealing is one of the final steps to ensure restoration, so make sure it simplifies the process rather than adding unnecessary steps.

Sealer should be suited to the environment in order to streamline the process of returning the structure to its pre-damage state. If adding the sealer makes cleanup more difficult, it is not the right kind or it may not be needed at all.

Is the Sealant Sustainable for the Future?

Finally, smoke damage sealer is a step intended to ensure sustainability of the restored space. Make sure you select a coating that will continue to perform its purpose and hold up over time, protecting the structure from stains, odors and chemicals well into the future and giving the building a long second life.

Types of Fire and Smoke Damage Sealers

Now that you know the critical considerations involved in choosing a well-suited sealer, you should become familiar with the different categories of sealers, along with their attributes, capabilities and limitations.

Selecting the appropriate sealer for application in a particular job is a matter of balancing the capabilities and limitations with the project’s most pressing needs and considering the criteria based on preferences including price, performance, personal protective equipment (PPE) requirements and sustainability.

types of sealers

Available sealers are mainly differentiated based on chemical formulation, and they fit into four categories:

  • Water-based
  • Shellac
  • Alkyd
  • Fixatives

Water-Based Fire and Smoke Damage Sealers

This type of sealer is made up of acrylic polymer systems sometimes blended with specialty resins in a water-based vehicle. Some water-based solutions — like RECON smoke sealer — are specifically intended for fire damage restoration and formulated to fit its needs. Professionals typically use this category of sealer for sealing stains, and it is available through professional restoration distribution centers at a similar or lower cost than shellac.

Water-based sealers are useful because they boast the capability to seal smoke odor while still offering water vapor permeability, meaning they will not develop condensation layers. They are also highly flexible and have a minimal odor and a low volatile organic content (VOC) level. As opposed to other types of sealer, this category is relatively inoffensive to environments or occupants with high chemical sensitivities, and it does not need any special handling for excess waste disposal. It also has no extra PPE requirements.

water based sealer

Water-based sealer is versatile, available in a multitude of tints, colors and finishes from matte to gloss. It is also extremely safe, posing no threats in terms of flammability and combustibility.

For all their excellent qualities, water-based sealers do possess a few limitations, including:

  • A greater preparation period requirement
  • A softness to their cured film
  • A variability in drying time
  • A changeability in stain-blocking performance — while some sealers are effective with only one coat, others may need two applications or more

They are also sensitive to material types, meaning high-solvent topcoats can deteriorate them, and they can be repelled by high-silicone content in surfaces.

You cannot use this type of sealer at surface and air temperatures below 45 degrees Fahrenheit, and not all water-based solutions are applicable in the same way, meaning some require brushes or rollers, while others come as airless sprays.

Shellac Fire and Smoke Damage Sealers

Composed primarily of processed lac resin, which is secreted by insects native to Indonesia and India, this sealer is created through suspension in alcohol. In the past, shellac has been the most commonly used sealer in fire damage restoration because of its prime ability to control fire odor. In fact, it boasts a decades-long history of successfully sealing smoke odor in treated surfaces. This sealer is available at almost all home paint centers and retail paint stores, and it is the most expensive type.

Shellac possesses multiple useful characteristics, including its ability to be cured and applied at much lower temperatures than other sealer formulations — down to 10 degrees Fahrenheit. It can also:

  • Adhere to tough or difficult surface conditions
  • Accept almost any type of top coat as a primer
  • Dry in less than 30 minutes for maximum restorative efficiency

shellac sealer

When dry, the cured finish is especially hard in comparison to other sealers and is ideal for stopping stains.

In addition to its commendable qualities, shellac possesses some limitations, so make sure its characteristics fit with your project.

This particular sealer is impermeable to water vapor transmission, meaning it can trap moisture and form a barrier of condensation. It can also be brittle when exposed to direct impact, making it an unsuitable choice for outdoor use. Be mindful that shellac requires extra attention to detail with denatured alcohol cleanup, and exposing its vapors to ignition can be a hazard.

Shellac also needs special handling — in the form of solvent recycling — for the disposal of excess material. While it serves to bar smoke odors, it also leaves behind an unpleasant lacquer odor for up to a week, which can require carbon filtration to eliminate completely. It also requires PPE for application, such as protective respiratory equipment to make inhalation safe, and you should pay attention to regulations regarding maximum VOCs, which can make it unavailable in certain areas.

Alkyd-Based Fire and Smoke Damage Sealers

Alkyd primers are oil-based and typically used more frequently for sealing stains from water damage. None are technically designated for fire restoration use, but they can fulfill these kinds of applications. Water-based alkyds and other hybrid coatings are currently emerging within this category. Alkyds are typically available in home centers and retail paint stores, and they are one of the least-expensive formulations of sealers.

alkyd primer

Alkyds have a number of positive attributes, including their toleration of difficult or imperfect surface conditions, excellent stain blocking abilities and quick drying capabilities. This sealer is also easy to sand, and after thorough curing, it accepts almost any oil- or water-based topcoat as a primer.

Some of alkyd-based sealers’ limitations include:

  • Uncertain permeability or lack of permeability
  • Expected VOC restrictions
  • PPE requirements
  • Flammability and combustibility
  • Persistently lingering odor
  • Specialized waste handling requirements

Alkyds also need extensive mixing before application, and they involve a lengthy cleanup process with mineral spirits, which can increase exposure to solvents and cost more in labor and productivity.

Fixatives Fire and Smoke Damage Sealers

Fixative sealer formulations are especially low in solids, and they help residual particulates adhere to surfaces, keeping them from contaminating the air and becoming respirable. This can be useful in isolating and eliminating toxins to stop further circulation after fire damage cleaning, but it is not particularly suited to avoiding further surface damage or keeping smoke stains from seeping, because it forms no tangible film.

The Do’s and Don’ts of Smoke Damage Sealers

With the details of sealer uses, categories and considerations under your belt, you are almost ready to incorporate them properly into your fire damage restoration projects. Just make sure you follow these crucial do’s and do nots with any smoke damage sealer application process.


    • Consider the needs of the particular project. These may include environment, exposure, level of damage and future function of the structure. Being careless with choosing your sealer can mean the site will not reach its full restoration potential in the future, and it can lead to later problems down the line.
    • Use a product intended for fire or smoke damage. Be especially careful to select a sealer you know addresses smoke damage and odor, especially in a structure with extensive damage or a sensitive environment. As the categories above indicate, some sealers — like alkyds — are intended for other purposes, so approach them with caution and always choose the product specifically designed to do the right job.
    • Pay attention to the preparation of your sealer. Some sealers require extensive mixing or safety preparation before use, and failing to follow these requirements or using them incorrectly can lead to damage or dangerous conditions. Even before selecting your sealer, make sure you know exactly what is involved in its preparation and application.

pay attention to sealer preparation

  • Perform proper cleanup and waste disposal. Some sealers are safer, while others are flammable, hazardous, high in VOC and specific about PPE and toxic waste requirements. To ensure health, safety and effectiveness, make sure you are aware of how to properly handle and dispose of all materials you use.

Do not:

    • Use sealers to cover up poor work. It is imperative that a structure is fully cleaned, deodorized and decontaminated before the application of any smoke damage sealer. Sealers cannot cover remaining contaminants or incomplete cleanup work — they can only serve to prevent additional stain spreading and odor escape.
    • Use just any paint primer. Sealers are specially formulated for damage treatment and are the only coatings you can use to cover smoke damage and block smoke odors. Using an ordinary paint primer on smoke- and fire-damaged surfaces creates an incompatible situation and will only lead to further damage to the surface.

do not use just any paint primer

  • Use sealers interchangeably. Every sealer has a unique set of characteristics, properties and limitations that make it more suitable to certain environments and situations. Never assume two different types of sealer will have the same effect or that you do not need to research their use in relation to the particular project. Pick the best-suited sealer and do not combine types.
  • Be careless with application and cleanup. Just like every sealer is different in properties, the procedures for preparing, applying and disposing of the coating vary with the type of formulation. Pay close attention to the directions for handling your particular sealer to ensure the coating is effective, the procedure is safe and the chemical cleanup is properly performed.

Use smoke damage sealers with care and consideration at all times, and best of luck in your fire damage restoration projects.