Fire Resistant Paint
Hadi Sapre
Fire-resistant paints are usually ASTM E-119 tested and certified. ASTM E-119 measures the the time it takes for a coating to fail under extreme heat and flame. Usually these fire ratings can last anywhere from 30 minutes up to 2 hours.
In contrast, most fire retardant paints are not ASTM E-119 tested or compliant. They prevent flame spread and typically have an ASTM E-84 rating. If a building material catches fire, the fire retardant paint works to slow the rate that the flames spread.
Two of the most important types of fire resistant paint are intumescent and cementitious paint formats. Cementitious coatings are an older fireproofing that creates a thicker barrier with a cement-based mixture and a binder that adheres to the substrate. Cement is naturally fire resistant, so the cement essentially augments the paint with fire resistant properties.
Cementitious coatings began surfacing in the mid-1900s when durable fireproofing solutions were needed. Concrete enhances the fire strength of a steel building, thus making cementitious paints an option. Over time, as dense concrete became too bulky, lighter cement paint methods were created. This type of coating is best in areas with low moisture exposure, as high moisture can cause an excess of corrosion and can reduce the effectiveness. Two of the biggest benefits of this coating are its affordability, especially for larger projects as well as its lightweight format.
Intumescent paints are relatively newer to the market but show excellent fire ratings and durability. Rather than being mixed with concrete to provide resistance, these coatings expand and char when introduced to flames. Intumescent coatings have been known to swell up to 25 times their original thickness when exposed to fire! The expansion of this coating is vital, as it allows for the volume to increase and the density to decrease, which in turn slows down the heating process. Intumescent paints are easier to apply, have reduced labor costs, and do not allow for gaps, making them better for moist environments. However, this paint is highly sensitive to changes during curing time and can be a costlier choice if multiple coats are needed.
While both formulas have their benefits and disadvantages, the general fireproofing industry often recommends intumescent paint for the majority of common applications. Cementitious paints are not the best for aesthetic appeal and can add weight, while intumescent paints blend into the visuals of the project.
Water-based fire resistant paint: Water-based intumescent paints have smoother textures and have less odor than other options. Water-based fireproofing also have fewer VOCs, making them more likely to pass EPA regulations. However, water-based paints usually require additional layers of paint and the dry times are longer. These types of coatings work best in conditioned, indoor environments where odor and appearance are chief concerns.
Solvent-based fire resistant paint: Solvent-based coatings have reduced drying times and are more suitable in humid or hot environments. However, solvent-based paints do have stronger odors and more VOCs, making them unsuitable for certain indoor environments. Solvent-based intumescent paints are typically better for field maintenance and outdoor projects.
Before selecting the paint for your project, it is important to pay close attention to the fire rating standards needed in your specific project. While there are a variety of standards, certain standards must be met for different styles of application. Here is a look at some of the most common ratings and their meanings:
Disclaimer: Our understanding of these standards is based on readily available information. Facility managers, building owners, and engineers should ALWAYS consult a fireproofing expert and understand their local laws before making critical decisions about their fireproofing needs.
Insl-x Fire Retardant Paint is a high-quality latex decorative, intumescent, fire retardant coating for interior ceilings, walls and trim. This product provides a high-hiding flat finish that retards flame spread by reacting to heat and forming a thick cellular char blanket (intumescence). By reducing excessive heat penetration, this product retards flame spread and minimizes smoke generation. It is suitable for primed or previously painted wood, drywall, cellulose tile, cured plaster, masonry and metal. It applies like a conventional latex paint, low in VOCs, and washes without spotting.
What client's climate zone (location)? Open cell foam in an attic is problematic in cooler parts of the country. (See -cell-spray-foam-and-damp-roof-sheathing.) So there could be a moisture/rot issue.
Reports suggest bad foam jobs usually smell like rotten fish. This does not sound like that sort of situation. It probably would be worthwhile to hire a RESNET professional to inspect the project and determine what is going on.
I am also in the south shore area and have the same exact problem. It has been 1 yr and I keep the attic extremely dry with a de-humidifier but when spring and summer roll around and the temp goes up, the smell becomes strong no matter the low humidity.
- Per a previous commenter, add an exhaust fan, sending air from the conditioned attic to outdoors. This will increase air change in the attic (diluting odors), and draw conditioned air (assuming air conditioner running) from the main house into the attic (see the Cool Hand Luke 'communication' comments). Lastly, if the exhaust fan is large enough, airflow will generally go from the house into the attic, thus 'containing' the odors.
- Add a dehumidifier. This will directly address the condensation problems occurring. Also, it is *possible* (not sure how likely) that this might reduce the odor issue. Odors are typically a function of temperature and humidity--we can't do much about the temperature, but reducing humidity might make chemicals 'less active' (less likely to react or evaporate).
John,
The sweating of the ductwork is the key to the mystery. There is a moisture issue in the space caused by insufficient air exchange. I would suspect that the old insulation/vapor retarder may still be in the floor of the attic space. They have in intent created a conditioned space but left out the means by which to condition it. Be sure to remove any insulation from the floor, tie the attic into the air handler of the main house to circulate/exchange air from the attic and/or install an air exchanger to control the humidity.
I have the same issue. It been 1 year since the installation and the paint smells bad. I paid for it and now very sorry contactor used it on top of spray foam. This is ridiculous, read so much before doing spray foam, read about all the issues, and it's the stupid paint that ended up causing these nightmares
Ps. My spray foam guy has been in business for a long time, it's not like I picked some cheapo contractor. He did alot of houses with the same paint and smell went away. The difference is that in my case, house is not under construction and there is zero venting on the attic. But I still figured 1 year should take care of the smell......I guess I was wrong.
This is 100% a failure to design for proper conditioning of the attic space. You have made this part of the interior envelop and it needs to be conditioned just as any other area of the house. Not a paint or foam issue purely a design issue. Install and HRV/ERV and include the attic space in the home ventilation system, problem solved.
Your foam was made in your attic at what ever the temp and humidity happened to be that day and the chemicals were mixed by setting adjusted by your installer in the field to what looks right that day.
I am not 100% sure what the smell is, but it smells like oil based paint or something. When I used oil based stain blocker in room, it smelled similar and took like a week to get the smell out, and I only applied it to effected small area.
So I understand that oil based paint can take a while to not stink but a year seems alot and something is wrong.
Just spoke with building contractor that works with spray foam guy. He said when they do this job, it's the paint that always smells and takes a while to get the smell out even in vented area. Waiting for call back from spray foam guy......
Spoke with spray foam contractor. He said paint is smelly but it's water based paint (none toxic) and the reason why it smells is because there is no ventilation. Also suggested I change HVAC filter since it can absorb the smell too (my filter is from last year, still pretty clean that's why I didn't bother)
Paint manufacturer also said that space must be ventilated for several days with fresh air for paint to cure and smell to go away. Shouldn't come back after that. Going for vacation for 2 week soon. Will try to at least open the attic, maybe will help along with EVR running almost 24/7
You NEED ventilation for the smell to go away. Ideally you want "cross flow" ventilation, with air coming IN one end of the attic and blowing OUT the other. I would setup some box fans to blow OUT from one end, with the other end open. This will depressurize the attic slightly, helping to keep the smell from leaking into your home. You want to run that setup for at least 2-3 days or so. I typically recommend doing the spray foam work at the end of the week, then airing things out over the weekend and taking a trip somewhere over that period.
Thank you for the info - yeah the attic is completely encapsulated and I did leave the entry way open for a few days with a small fan running and the upstairs windows while we were away. While the smell isn't bad by any means and it has gotten better it's still very present every time I go up to the attic.
You need the fans setup for crossflow. That means not both blowing in, and not both blowing out, if they are at opposite ends of the space. You want air to come in one end of the attic and exhaust out the other. While it may seem that both blowing out will "suck out the smell", it doesn't actually work that way -- you need one blowing the smell out, and another open end (open window, open door, etc.) to let fresh air in to replace the smelly air you blew out. With air constantly moving through the space like that, you keep the concentration of the "smelly stuff" in the air low, which allows for the maximum amount of remaining "smelly stuff" to evaporate out of the installed materials. That's what you need to do to clear things up.
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