Sniffing out the source of corrosion in new homes

The culprit: sulphur

The culprit: sulphur


Robert DeMott

PhD, DABT, Managing Principal
T: +1 813 628 4325

Residential builders and property management teams in Florida and Louisiana faced coincident challenges of odour complaints and unusual corrosion rates for HVAC equipment in some newly constructed homes. Our investigations of the odour complaints led to solving the corrosion problem as well. We identified certain sulphur-containing gases present in usual circumstances, then demonstrated these to be the cause of HVAC failures due to their corrosivity toward copper, brass and silver surfaces.

Our scientists designed testing protocols that revealed not only the gases involved, but the chemical reactions producing them. We linked the corrosive gases to a specialized type of sulphur in certain Chinese gypsum wallboard (drywall). Our experts also discovered the progressive nature of the related corrosion, which was a critical factor for determining effective repair approaches.

Setting standards

Ramboll was the first to describe this phenomenon to USEPA and the US Consumer Product Safety Commission. Our research and briefings to state and federal agencies became the basis for the inspection protocol established by the State of Florida and many elements of the repair protocol specified by the US Consumer Product Safety Commission.

Ramboll’s methods and documentation became the benchmark for submissions for settlement claims and insurance cost recovery.

Setting things right

Ramboll has overseen drywall replacement and repairs to more than 2,700 homes.

With this project, we discovered the source of a new problem, helped inform and create the solution and ultimately saw residential real estate transactions start requiring evaluation for Chinese drywall in routine home inspections.


First Floor, Emerald Building
Oud Metha Road
PO Box 116921, Dubai, UAE
Tel:+971 4 334 3616
Fax:+971 4 334 3617


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