Lab Tests Find Everyday Tape Beats Sandbags at Keeping Floodwater Out of Homes

When flood warnings are issued, sandbags are often the first thing people reach for. New laboratory tests suggest something far lighter and cheaper may work much better. Researchers at the University of Hull's purpose-built property flood resilience facility, PFRlab, tested temporary ways of keeping water out of doorways on behalf of Flood Re, and found that every tape they tried beat sandbags.

The tests covered six common types of door at water depths of up to 600 millimetres, about two feet, chosen to mimic the shallow but damaging June 2007 floods in Hull, which affected more than 8,600 homes and 1,300 businesses. Compared with an unprotected door, flood putty tape, a butyl-style product, cut leakage by up to 99% and was up to ten times more effective than sandbags under test conditions. Good-quality wide duct tape reduced leakage by 97% to 98% and offered the best overall balance of performance, price, durability and speed. Even the weakest tape achieved about 80%, while sandbags managed around 70%.

There were other useful lessons. Tape worked better on the outside of a door than on the inside, and before any protection was added, a standard outward-opening door let in 74% less water than an inward-opening one. Temporary demountable barriers could stop water completely when fitted correctly, but results ranged from total protection to failure, and correct installation needed specialist knowledge. The University of Hull's report, published on Zenodo, concludes that performance varies considerably between products and that some low-cost measures can match much more expensive ones.

"Sandbags remain a symbol of flood protection, but these tests turn that assumption on its head," said Jonathan Kassian, head of flood resilience at Flood Re. Floods minister Emma Hardy welcomed the research, saying simple, affordable products could make a real difference for communities at risk. The findings matter: the Environment Agency estimates that about 4.6 million properties in England are in areas at risk of surface water flooding.

The researchers are clear about the limits. Tape is not a substitute for permanent, professionally specified flood resilience measures, and it cannot seal walls, floors or drains. But for households facing shallow flooding, keeping a roll of flood putty tape or wide duct tape at home could be a quick, low-cost first line of defence.