1. How to Find Asbestos Insulation Inside Walls (for Building Demolition)
Joseph Burley
Freelance Enviro-Tech/Tri-Tech
Michigan Asbestos Building Inspector #A13808
Recently during a pre-demo survey of a house the builder client expressed amazement at
how easily I found the asbestos hidden inside the walls. I have never seen the method
described and always figured it was fairly obvious. However, if a builder didn't know
how it was done, I figured it was worth reviewing for those still learning the asbestos
survey business. This works for both hot-water and supply insulated pipe and duct
insulation. This example is based on a typical 2-story house with the basement but the
basic concepts can be applied to other house configurations or commercial buildings.
1. Draw a relatively to-scale plan of the house starting with an enlarged aerial and/or
assessor's shell plan to get the basic dimensions. Use outside window positions as a cue
for the room configurations. Map out each air duct or radiator in each room as well as
water supplies (sinks/shower/toilets). Check the supply water areas first for pipe hatches
or whether the piping goes straight down. Determine if the domestic is insulated--
typically it isn't for residential in my area, otherwise it needs to be accounted for using
the same method as for the heating system.
2. In the basement, map out where the risers enter the ceiling and match them up with the
radiators above. Two lines for each radiator. With ducts typically only the supply is
insulated but double check the returns anyways. Look for evidence of duct insulation
removal on bare ducts--sometimes its been removed from the basement facing but left
around the duct above the ceiling behind the register. Once the first floor risers are
accounted for, look at the remaining risers. Typically they are right below the
corresponding radiators/ducts on the second floor.
3. Connect the dots and project where on the first floor the risers should be hidden. Put on
your respirator, take careful aim with a sledgehammer and let it fly-- but not too hard--
you may not know the asbestos content of the plaster or drywall and you don't want to
crush the asbestos behind it. Hopefully, as shown below you find it on the first shot.
Good luck and happy hunting!
http://commonground.edrnet.com/posts/8d1d7f98cc