Transite – Bill Stone
ACI
Transite is a a trade name for a product manufactured by
Johns-Manville and was introduced to the building industry as early as the late
1920’s. Johns Manville is not the only
company that manufactured rigid panels and pipe using asbestos content. The addition of Transite asbestos to Portland
cement allowed the manufacture of strong and thin sheet products, typically the
amount of asbestos content was somewhere between 12-50%. Due to its fire retardant nature, Transite
was widely used in residential construction and is often found in siding, flue
pipes and in sheet form lining the areas around furnaces and hot water tanks
but it was also widely used in siding.
When used in siding it often mimicked cedar shingle siding
but unlike cedar, which is a natural and imperfect product, Transite shingle
siding will be uniform in nature. When
painted, the asbestos is contained, but when paint fails, weathering can
release asbestos fibers to the air. In
addition, paint prep work such as scraping can release the fibers as can peeling
paint itself.
Transite siding.
Transite is easily identified; it is very rigid and has a
gray cement color to it. Since one of
its leading benefits was its fireproof nature, it will be often found lining
utility rooms or in flues. Leading
producer Johns Manville’ materials typically have a cloth like pattern to
it. Remember that without lab testing,
there is no way of knowing the asbestos content. Asbestos in Transite was phased out by the
1980s, the asbestos content being replaced with crystalline silica which has
its own list of health concerns.
Transite ductwork.
Due to its rigidity, the presence of Transite does not
necessarily mean asbestos fibers are airborne.
Unlike boiler insulation wrapping, Transite boards require force to
damage them, but crumbling or broken pieces of Transite board are a problem and
if Transite is subject to continued moisture, it can delaminate. Areas where this may occur are in slab
ductwork and when used as appliance venting.
Sometimes the Transite extends above the roofline, in other cases it can
be subject to high moisture in flue pipe from condensation etc.
What to do if you find Transite? I recently inspected a slab home with
Transite ductwork and followed the progress as the potential buyers attempted
to determine the potential health risk.
My clients first contacted several duct cleaning services and asked if
they ever clean ducts in these homes.
The answer was no, but I believe if they weren’t informed of the
Transite first, they would have cleaned the ducts without any
questions/concerns. Several asbestos
abatement contractors were called out.
All agreed that the product was Transite and it would most certainly
contain asbestos based on the year of construction, which was the late
1960’s. All advised against any lab work
as they firmly believed it would have asbestos in it. One contractor said he could apply a coating
to the ductwork, but could not guarantee full coverage. None of the contractors had camera snakes to
determine existing condition or to inspect after duct coatings were
applied. It seems that it is difficult
to get competent abatement contractors at the residential level as the leading
companies are working in the more lucrative commercial arena.
As home inspectors, per the ASHI standards, we are not
required to even identify items such as Transite, but I feel it is a disservice
to not inform our clients about these risks.
Unfortunately, the list of solutions to the problem you’ve identified
will be short and your clients may find it impossible to mitigate the risks to
their satisfaction.