Research focuses on deck safety, awareness

More people are injured in accidents related to faulty wooden decks and balconies than from injuries stemming from all other wood building components combined.


Joe Loferski points out the critical connection between the deck ledger and the house. Joe Loferski points out the critical connection between the deck ledger and the house. Research shows that this connection is the primary cause of deck collapses.

Joe Loferski, a wood science and forest products professor in the College of Natural Resources, has been working to improve deck safety for the past 10 years. His research and workshops have not only increased awareness about the dangers of faulty decks, but have helped lower the number of deck incidents around the country.

Loferski began to investigate deck safety after he started to see a pattern of deck collapses across the United States.

“I started wondering what was going on, since we don’t often see roofs, walls, or floors of houses collapsing,” he explained.

Even though the design loads are the same for decks as they are for the floors, decks still falter or collapse while floors rarely do. In many cases, decks collapse while people are on, near, or under them, which can cause serious injury or even death.


Joe Loferski explains that notching guardrail posts at the bottom severely reduces their strength. Joe Loferski explains that notching guardrail posts at the bottom severely reduces their strength and can cause the guardrail to collapse when people lean against it.

Loferski began constructing decks and simulating collapses in Virginia Tech’s complete wood engineering laboratory. By testing thousands of pounds of load on critical components of the sample decks, he was able to pinpoint the problem. Decks collapse because of weaknesses, instability, and lack of support where the deck connects to the structure and where the guardrail attaches to the deck.

“The connection between the deck and the house is the most critical, because when that fails, the entire deck falls to the ground,” Loferski said. “Furthermore, deck guardrails can give way when people lean against them, causing falls from the deck to the ground.”

Loferski and his team spent several years researching and ultimately solving the critical connection problem between the deck and the house.

Although their research was published in technical and scientific journals, Loferski said he realized he wasn’t reaching the critical audience — builders, building inspectors, and those working in construction.

In an effort to reach those in positions to directly impact issues with deck safety, Loferski published a series of articles in Building Standards, the official publication of the International Conference of Building Officials, as well as The Journal of Light Construction, the journal for builders.


Deck underside This deck's underside shows a support post and two girders attached. It appears to be in good condition overall with no obvious signs of decay. Two of the bolts are corroding, however, and may have to be replaced.

Loferski then shifted his research focus to the connection between the guardrail and the deck. Building sample guardrails helped the team identify weaknesses in the connection and in the guardrail itself, and develop solutions such as improving the connection of the guardrail post to the deck.

“Once we solved both problems, my colleague, engineering professor emeritus Frank Woeste, and I started to conduct workshops and short courses to educate builders,” said Loferski.

Not only has Loferski increased deck safety awareness across the nation, he has also affected the U.S. building codes. Because Loferski’s research was with East Coast species of wood, he teamed up with researchers from Washington State University who tested western species, so that they could pool their data and introduce new building codes that were applicable nationwide. The International Code Council adopted the team’s research and will soon require builders to follow the guidelines.

“If builders use the methods we developed, decks will not collapse,” assured Loferski.

But, changes in building codes can only ensure the safety of decks that have not yet been constructed.

“There are more existing decks now than will be built in the next 10 to 20 years,” explained Loferski. One problem in the past has been that building inspectors, builders, and even homeowners do not know what structural dangers to look for. Many different factors play into the safety and structural soundness of wooden decks and balconies.

“You have to look at all the connections — the condition of the wood, whether it is pressure-treated or decayed, the structure of the deck, the size of the fasteners, the number of bolts, and that they are spaced and installed correctly,” Loferski said.

By translating his data into practice for builders and homeowners alike, Loferski has helped in reducing preventable occurrences, avoiding accidents, and saving lives.

  • For more information on this topic, contact Lynn Davis at or (540) 231-6157.

Book advises professionals and homeowners

Joe Loferski published a book along with Frank Woeste and Cheryl Anderson, a 2003 graduate student, about inspecting decks and balconies. 

The Manual for the Inspection of Residential Wood Decks and Balconies instructs and advises building code officials, home inspectors, and other building professionals, as well as homeowners, on how to prepare, analyze, and look for deck safety issues.

Published in cooperation with the International Code Council, the manual is available to both professionals and the general public.

Resources for inspecting your deck

Because many homes have existing decks and balconies, it is important for homeowners to ensure that their decks are safe. 

Loferski urges all homeowners to have their decks inspected and repaired if any risks are found. The North American Deck and Railing Association’s Deck Safety Program offers homeowners articles, a consumer checklist of potential risks, and a deck evaluation form to check your deck’s stability. 

Find qualified deck builders and contractors in your area to determine if your deck is secure. For further information about inspections and what you can do to prevent these accidents, visit the following websites:

Share this


Spotlight Archive

Look through previous Spotlight stories

Access the archives