Chinese Drywall Remediation

On April 2nd, the CPSC released their guidance on a remediation process for homes affected by Chinese drywall.  Their recommendations are nearly identical to the advise we have delivered to our clients for several months.  The defective drywall must be removed.  Although they did not evaluate the systems that claim to cure Chinese drywall without removing the material, they did dispute the claim of the presence of sulfur producing bacteria as the cause of the problem.  Some of these systems claim to treat and kill this bacteria as the basis of their efficacy.  

Certified Chinese Drywall Testing, LLC is in the process of validating a testing procedure for clearing the framing members of cross contamination.  This clearance test will guarantee that the home is not being reconstructed around contaminated framing.

Chinese drywall remediation is the process of removing the defective drywall from the home and replacing it with domestic drywall.  At initial glance, that scope of work seems relatively simple.  If you take a closer look however, it is easy to see how Chinese drywall remediation can cost upwards of $60 per square foot.

In order to remediate Chinese drywall, the first step is to remove the defective drywall.  Before one is able to remove the defective material in a typical home, cabinets must be removed.  In addition, appliance, furniture, carpeting, and counter tops must also be removed.  The second step of Chinese drywall remediation is the removal of the defective drywall.  

Removing Chinese drywall reveals behind the wall mechanicals.  These systems – the HVAC, electrical, and plumbing – can all be affected by Chinese drywall remediation.  Some protocols are calling for duct cleaning and replacement of the HVAC equipment.  Most new homes were built with PVC plumbing, which is not affected by defective drywall, however the copper tails that come out of the water heater need to be replaced.  The most significant controversy as it applies to Chinese drywall remediation involves the electrical wiring.  

Without a doubt, copper is dramatically affected by the gases produced by defective drywall.  The average homes contains hundreds of feet of copper wire that serves to provide power to the home – switches, outlets, etc.  The corrosion that results can increase the conductor's resistance to electrical current.  As a result, the wiring can give off increased levels of heat.  A hot wire fastened to a wood framing member is a recipe for disaster.  

The controversy specifically involves the process necessary to remediate the effects of Chinese drywall on electric wiring.  Wiring that is installed in a home is insulated with a rubber/plastic coating.  This coating protects the wiring and insulates it from other components in a building.  As it relates to defective drywall, this coating theoretically protects the wiring from the gases produced.  Only the areas where the insulation has been removed – where the wiring ties into outlets, switches, the panel box, etc – would need to be repaired.   These repairs could involves simply cutting off the corroded ends and re-terminating the wiring or cleaning the ends of their corrosion.  Theoretically, the remainder of the wiring is protected by the insulation and was not exposed to the corrosive gases.

In reality, the construction process is one of the few processes now-a-days that is not done within the confines of a controlled facility.  Building a vehicle to exacting specifications is possible in no small part because the process happens in a manufacturing facility.  Building a home, however, does not happen in a controlled environment.  Wiring is typically secured to wood framing members throughout a typical home with special staples.  While these staples are designed not to puncture the insulation on the wiring, it is common for a ladder to be dropped on wiring that is running between stud bays or for the wiring to be impacted at some point during construction.  As a result, it is reasonable to expect that the insulation of electrical wiring would be damaged in areas other than where it ties into an outlet box or switch.  For this reason, many Chinese drywall remediation protocols call for the home to be completely re-wired.  Because this adds additional cost to the process, many builders and/or contractors resist or don't recommend re-wiring a home.  Homeowners should be aware of the fact that rewiring the home may be a necessary step in the drywall remediation process.

A further complication of Chinese drywall remediation relates to cross-contamination.  Reports seem to indicate that defective drywall can contaminate the adjacent building materials.  For this reason, the recommendation is that all drywall be removed from the home, even if it is not Chinese drywall.  Some builders will leave the ceiling drywall in the home or try to remove just the defective drywall.  While there is some evidence to suggest that the cross-contamination could be resolved by allowing the home to “air out,” the bulk of the experts recommend that all drywall be removed from the home.

The cross-contamination problem is evident in another phase of Chinese drywall remediation.  After the defective drywall has been removed from the home, many contractors have witnessed cross-contamination into the wood framing members.  This contamination can penetrate a typical 2x4 framing stud up to 3/4” deep.  For this reason, Chinese drywall remediation protocols often involve a period of induced off-gassing.  Off-gassing is the process by which defective drywall creates the corrosive indoor air environment.  Specific compounds are released by Chinese drywall in the form of a gas (off-gassing), combining with latent airborne humidity to create the corrosive gases.  In order to induce and accelerate this process as part of a Chinese drywall remediation protocol, the home is heated to 120 degrees.  As a result the gases are released from the contaminated wood at more dramatically increased rate.  While the home is being heated and the gas is being released, Chinese drywall remediation protocols call for the use of fans and air scrubbers to clean the air of the gases.  Fans are set up in windows and doors to encourage air exchange and air scrubbers are set up to clean the remaining air of the contaminants.  This process should be continued until all of the cross-contamination has been mitigated.

Prior to installing new drywall, the home should be tested for any remaining cross-contaminants.  A Chinese drywall remediation protocol that does not include a certification that the home is clean of contaminants prior to re-installing new drywall can offer no guarantee that the remediation process was successful.  This certification may be necessary in the future in order to sell a home that has been remediated for Chinese drywall or to obtain home owner's insurance on the home.