DF Technical & Consulting Services Ltd.
Indoor Air Quality and Environmental Experts


Asbestos in your Home

What is it and where do we find it

Asbestos is the common name for the flexible fibres separated from the mineral silicate rock mined in various locations in North America and other parts of the world.

The main properties that make asbestos useful are its incombustibility (will not burn), strength and flexibility when separated into fibres. It is also effective as a reinforcing or binding agent when combined with cement or plastic.

Many products which at one time contained asbestos are either no longer in use or have been replaced. The typical cut off point for use of Asbestos is regarded as 1982 though the time line was earlier, some contractors appeared to use old inventory in construction as late as 1982.  The uses for asbestos ranged from products in which the fibres were well bound to friable products in which the fibres could easily become airborne. The construction industry was the main user of asbestos products. Sprayed insulation, stucco and joint cements manufactured in Canada and the United States no longer contain asbestos in an unbound form.

Building materials containing asbestos in a bound form are typically found in the following locations and products:

Building exteriors

  • asbestos cement siding panels – flat, corrugated, shingles or accent panels
  • asbestos cement soffits – flat or perforated panels
  • asbestos cement roof panels – corrugated
  • roofing felts and mastics
  • building overhangs – thermal spray
  • stucco
  • brick and block mortar
  • loose fill insulation in exterior wall cavities (vermiculite)


  • vinyl asbestos tiles (VAT)
  • sheet vinyl flooring (asbestos paper backing)
  • floor leveling compound


  • t-bar ceiling tile
  • asbestos cement ceiling tile
  • acoustic and stippled finishes
  • plaster or drywall jointing materials


  • plaster or drywall jointing materials
  • stippled finishes
  • thermal spray
  • asbestos cement panels

Service areas

  • insulation in boiler rooms — boilers, vessels, pipes, ducts, incinerators, floors,
  • ceilings, walls
  • fan rooms — insulation on pipes, ducts, chillers, floors, ceilings, walls
  • machine rooms — insulation on pipes, ducts, floors, ceilings, walls
  • crawl spaces — insulation on pipes, ducts
  • wall cavities, insulation above ceiling spaces — pipe and duct chases, pipes, ducts


fireproofing spray on beams, decks, joists, columns and other structural members

Pipes (insulation on either exposed or concealed pipes)

  • steam and hot water heating supply and return lines
  • domestic water supply and drain lines
  • chilled water lines
  • rain water and sanitary lines — asbestos cement or bell and spigot cast iron,
  • insulated or bare pipe
  • gaskets in flanged pipe joints


  • incandescent light fixture backing
  • wire insulation
  • elevator brake shoes
  • heating cabinet panels (asbestos cement)
  • duct tape
  • duct expansion/vibration isolation joints

Building products containing asbestos in an unbound or loosely bound form include:

  • insulating cements
  • sprayed insulation — fire resistant, acoustic, thermal, condensation control
  • insulation block — magnesia or calcium silicate
  • textiles — not saturated, for lagging, curtains or clothing
  • vermiculite insulation (may contain tremolite asbestos as a contaminant) – produced from the Libby, Montana mine by W.R. Grace and Company and known by the brand name “Zonolite”.

The list of products containing asbestos which are used in applications other than construction include:

  • bound-fibre products
  • non-bound fibre products such as millboards and papers
  • some electrical insulation and filters or filter aids

Non-friable products which may contain asbestos pose little danger of releasing airborne fibres unless they are cut, broken, sawn, ground, sanded or are in deteriorating condition.
This is a partial list more refined to homes and areas in which a home may contain asbestos.

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Getting to the Bottom of Mould in your Building

Moulds, from the Kingdom Fungi, are microscopic organisms that can be found virtually everywhere, indoors and outdoors.  They are a natural part of the decay and decomposition cycle of all organic materials.  Organic materials refer to those materials that are or were once living, such as leaves, grass, wood, papers and foods.  There are reportedly more than 100,000 species of mould and some estimates of 1,000,000 species of mould present on the earth today.  Also contained within the Fungi Kingdom are Mildews and Yeasts.

Some of these moulds or fungi are favorable to us as we eat them with our salads and steaks, however other varieties are not quite so enjoyable.  Most moulds are regarded as allergen reaction producing or asthma triggers given the right conditions to most if not all humans.  In fact some mould species produce toxins in an effort to protect themselves and the areas in which they live. Unfortunately, some times these areas are in our homes making for an unwanted tenant in your home.

So what does mould look like to the average person! Mould as it grows will take on a wide variety of different colors depending on when you look at it during its life cycle, the material that it is growing on and finally the type or species of mould.  In fact during the early growth phases of many moulds there is no visible color and it is not until later on in the life cycle that the colors become present in the spore production phase.  Many resources talk about black mould and to be aware of this type of mould.  Not all black mould is the toxin producing mould, typically thought to be Stachybotrys.

Discoloration on a surface may be an indication of a mould problem within your home along with a musty or earthy odour.  If an odour exists with no visible indication the mould may be hidden from view, for example below a raised sub-floor, within a wall cavity or some other concealed area.  Just because you cannot see the growth does not mean that there is not a problem.

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