Last week I had the opportunity to attend the Chinese Drywall Technical Symposium in Tampa. Here is a recap on the Environ report on construction materials and remediation protocol.

Jamie Poole, PhD, CIH is with Environ International Corporation. They were one of the first research laboratories called in to test what has become known as “reactive, corrosive or tainted” sheetrock. Dr. Poole made some important points based on their findings. First off he stressed that corrosive sheetrock will continue offgassing for many years and that installation did not trigger a onetime release of stored up gasses. He stated that the scale or residue found on copper coils is sulfur based and not a case of oxidation of metals and that “simply removing the source of the gas is insufficient.” Dr. Poole stated that the scale or residue will continue to corrode metals it is sitting on, even when the source of the gasses is removed.

Bob DeMott, PhD, led the group through a presentation on chemical analysis. Mr. DeMott is a toxicologist with Environ. He discussed some of the chemicals found in the off gassing of tainted sheetrock such as carbonyl sulfide and carbon disulfide and differentiated for the audience the differences between metals affected corrosively versus typical oxidation.

An extremely significant part of his talk was based on Environs research on other building materials that might be impacted by off gassing. He stated that the off gassing would not impact non-porous materials such as tile. For porous materials such as wood, the off gasses will enter it but it will not be stored in a reservoir type condition and the gasses will leave it. They tested wooden home components including plywood, pressure treated lumber and furring strips in 54 houses that were in some stage of renovation, remodeling or repair and found that the potential damage was not significant due to off gassing. They also tested concrete by attaching chambers to the sides of block houses. This is huge news for those people who were speculating that the entire house, frame and shell, would need to come down if the gasses weakened the structure.

Many of the contractors present were hoping for guidelines or a program to start remediation and were disappointed. However, there was practical advice given, particularly by Environ based on some research work they had done and presented as a poster.

Jamie Poole presented key considerations for the repair of structures with defective drywall. He said that work should only be done in unoccupied structures, items that had potential re-use should be removed and stored elsewhere, tile be covered and protected but that all carpet and padding should be removed and thrown away since they are “dust magnets” and that ALL drywall be removed.

In terms of ancillary building components, he suggested that insulation, batting, interior duct work and air handlers and all regular and low voltage wiring be removed. While you can clean the internal air handling systems and duct work, it is labor intensive so he suggested it just be removed and replaced. He did state that the air conditioning compressor unit could stay. He said that typically all copper, brass and chrome plumbing components are being removed.

After demolition, then a cleaning and venting process should be followed. For cleaning he recommended a gross cleaning, a pre cleaning and then HEPA vacuuming using industrial quality equipment and fine filters to try to get as much particulate dust as possible. He then suggested ventilating the house before starting to rebuild. Later on an audience member asked how long a house should be ventilated and it was discussed that it should be from 2 weeks to a month. It was also discussed that the “airing” out period could be accelerated by heating and ozone but to be cautious using ozone around organics, fine fabric and other sensitive materials.

He did give a couple of heads up comments to homeowners and their contractors including making sure that all waste lines were properly capped during demolition and that homeowners should understand that some oxidation of copper is natural.

He said that current evidence does not support cross contamination of wood and concrete. He cited their own research (which should be posted under posters) using a 54 home study of wood components. He also said that cement based products such as durorock, gypcrete flooring and concrete block would not be impacted. They had found no detection of sulfur damage in concrete block based on 80 chamber tests that they did.

Poole stated that some oxidation on metal framing could be observed and should be ordinarily expected. They looked at truss plates, nails, metal framing and hurricane straps and did not see any reason for concern.

In closing, he stated that repairs to homes could be effective and successfully done and that exotic procedures were not warranted. Based on their objective evaluations of wood and concrete homeowners should be “ok” with those components left in place. He felt that adding other products to the mix “to make sure” could actually be more harmful than good because there might be a problem with those items down the road.

For a full copy of my notes go to www.Assetadvisorsandmanagers.com