Is There Asbestos in Stucco and Exterior Plaster?


    Technically speaking, exterior stucco does not contain asbestos particles in it. Although cement board, that is used for backing of stucco on exterior surface of building can contain asbestos. It can be dangerous for human health while demolishing.

    Biggest misleading factor in designated substance industry is calling materials names that don’t apply to them. Just like that, plaster siding is often called stucco. They are completely different but may look similar at finish stage.

    Plaster mix on other hand may or may not have dangerous asbestos in it. Installations of this product between 1930 to 1980 have higher chance of having designated substance and have to be properly remediated by licensed professionals.

    Nothing you read about is 100% sure, and even our information has to be backed by physical evidence. To know if there is asbestos in stucco of your home, complete lab test and DDS report.

    Why People Think Stucco Contains Asbestos

    If debate about asbestos in stucco and similar products exist, than many of you might have thought about the possibility of it being true. In fact most of people don’t know the answer and just guess where dangerous substance is present.

    We know of four reasons that some of you may think there is asbestos in stucco:

    • They Were Told so
    • Mistake It with Plaster
    • Stucco Backing Cement Board
    • Year of Installation

    The job of every asbestos related article is to educate everyone around. Way too many people die from long-term deceases caused by this substance and we all want to make the number lower every year.

    Understanding potential danger is first step of protecting yourself from it.

    They Were Told so – the only way to know this for certain is to do a lab test. Results will show if stucco or what you think looks like stucco has inside.

    Your friends, coworkers, clients or company boss can say whatever they want, but relying on their opinion can get you in trouble.

    Mistake It with Plaster – stucco looks very similar to plaster on exterior walls. Home owners that have never worked in construction industry may not know the difference at all.

    Plaster was and is tilled this day used in wide range of application. It can be poured into molds, installed on rough and smooth surfaces. Stucco is mixed with Portland cement and usually used only on exterior of house.

    Stucco Backing Cement Board – stucco finish is applied on top of something. In colder areas rigid insulation is used as underlay, but wormer regions mostly use it on top of cement boards.

    These cement boards could potentially have asbestos in it, but stucco never does. Therefore some people just say its stucco with dangerous material and not layer behind it.

    Year of Installation – Asbestos was used heavily in residential and commercial construction during mid-1900s. Knowing this may scare you every time you see stucco or plaster.

    Just because material was installed during the era of asbestos, doesn’t mean everything is contaminated. Check the facts with lab results and stay safe.

    Difference Between Stucco and Plaster

    Remodel On Point already mentioned that stucco and plaster look almost the same and nonprofessional can mistake one from another.

    Now it’s time to talk about three main differences between these finishing materials for exterior façade.

    1. Application/Installation Method
    2. Materials It’s Made of
    3. Potential Dangers and Asbestos in It

    Trades that work with stucco or plaster for many years know the difference and how each material should be treated. Those who are unfamiliar with details can see more detailed breakdown below.

    Application/Installation Method – Stucco is applied on hard surface with some type of grip. For better strength and crack avoidance, mesh is secured to exterior plywood or block wall.

    Plaster can literally hold on anything. It is more like paint or glue that reacts to harden into cement base substance. Most of molds for interior and exterior design are poured plaster.

    Materials It’s Made of – base of plaster materials is gypsum. It can be applied on surfaces like ceiling or wall, poured into molds or used to patch holes.

    Stucco’s initial base is always with Portland cement and lime products. Fiberglass particles are added for extra strength and tight grip.

    Potential Dangers and Asbestos in It – stucco by itself never has asbestos in it, while plaster can be contaminated. Don’t trust your instincts because cement board behind, insulation layer and adhesive glue can be with asbestos fibers.

    The biggest problem is differentiating one from another to be safe while working on removal.

    Why Was Asbestos Used in Stucco Cement Boards

    It is sad to say that asbestos was used in all sorts of construction materials just 50 years ago. It was added to tiles, concrete mix, insulation, roofing and many more products.

    Noon e new all the danger asbestos particles can cause to human health. That is mostly because effects were long term. Exposed workers could develop sickness 10 – 20 years later.

    Too bad studies did not start few decades after asbestos was produced and used almost everywhere. Hundreds of thousands (if not millions) of people were exposed to it.

    Asbestos particles increase durability, strength, insulation level to exterior plaster. Of course it was popular in manufacturing; especially the costs of production were so low.

    Is Plaster Asbestos Dangerous?

    Every type of asbestos contaminated material can cause harm when disturbed. What it means is while it sits quietly inside original material it does not pose any danger.

    When plaster or cement backing board behind stucco is cut, broken or demolished in any way that creates dust, asbestos particles escape and get airborne.

    Changing exterior façade becomes more challenging for workers. Most of them are not trained in handling designated substances.

    Technically home owners should notify all workers about hazards and presence of asbestos is definitely one of them. There have been cases when workers sued and won cases for not being aware of dangerous substance of work.

    Other Exterior Siding Materials that Contain Asbestos

    Besides Plaster and cement boards, there are plenty of siding materials that can be contaminated with asbestos. There is no reason to risk your health over a tiny pay check. Do your own due diligence and find out if exterior façade you work with is dangerous.

    Asbestos and other dangerous materials can be in:

    • Slate Tiles
    • Specialized Paints
    • Adhesive Materials
    • Vapor Barriers
    • Vinyl Siding

    Newly installed materials during renovation or new construction have very low chance of risk. Nevertheless the cost to test stucco or plaster for asbestos is not high. Only for $50 – $150 you can get lab results confirming whether material is contaminated or not.

    Steven H.
    Steven H.
    General Contractor and Home Builder with over 20 years of experience. Write and Edit educational posts for several Remodeling Blogs. Specialize in trade management and technical construction details.

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