In October 2026, new research from the University of Hull and Flood Re made headlines with a surprising finding: ordinary duct tape kept more floodwater out of a front door than sandbags did in laboratory tests.
It is a useful result, and a cheap roll of tape is something almost every household can keep in a drawer. But tape on its own is not a flood plan. Water finds other ways into a home, and what works in a test rig does not always work in a real flood.
This guide explains what the research found, why tape works in theory, where it falls short, and the other flood protection options worth considering for your home.
What did the duct tape flood research find?
The tests were carried out at the University of Hull's PFRlab with Flood Re and released during Flood Action Week. Modern timber, uPVC and composite doors were fitted by professionals, then water was raised against them in 5cm steps up to 600mm deep.
The key results were:
- Unprotected doors often leaked thousands of litres per hour at 600mm depth
- Wide, good quality duct tape applied to the outside of the door cut leakage by 97 to 98%
- Flood putty tape (similar to butyl tape) performed up to 10 times better than sandbags
- Even the weakest tape tested cut leakage by around 80%
- Sandbags, stacked with plastic sheeting, reduced leakage by around 70% at best
- Outward opening doors leaked 74% less than inward opening doors before any protection was added
Taping the outside of the door worked much better than taping the inside, because the water pressure pushes the tape against the frame rather than peeling it away.
Why does tape work in theory?
Most water that comes through a door does not come through the door itself. It comes through the gaps around it.
Typical leak points on a front door include:
- The joint between the door and the frame
- The threshold and the bottom of the door
- The joint between the frame and the brickwork
- Letterboxes, keyholes and cat flaps
Sandbags try to hold water back by mass, but water seeps through and between them. Tape seals the gaps directly. When it is stuck to a clean, dry surface, the water pressing against it helps hold it in place.
What are the limits of using tape for flood protection?
The researchers were clear that tape is a temporary measure and not a substitute for proper flood doors, barriers or a property flood resilience plan. Here is why.
Lab conditions are not flood conditions
In the tests, tape was applied by one person to clean, dry doors in 10 to 20 minutes. In a real flood you may be working in the rain, in the dark, on a wet or dirty frame, with very little warning. Tape does not stick well to wet surfaces.
A small percentage can still be a lot of water
A 98% reduction sounds close to watertight, but it depends on what you start with. If a door would leak 2,000 litres an hour, a 98% reduction still leaves around 40 litres an hour. Over a long flood, that can mean wet floors and damage.
Doors are not the only way in
Tape can only seal the gaps you can reach. Floodwater also enters through:
- Air bricks and vents
- Walls, especially porous brick and mortar joints
- Floors, through ground water rising from below
- Drains, toilets and sinks, when the sewer backs up
- Gaps where pipes and cables pass through walls
A taped door does nothing about any of these.
If you do use tape, how should you apply it?
Tape is still worth having as a last resort or a backup. If you use it:
- Use wide, heavy duty duct tape or flood putty tape
- Apply it to the outside of the door, before water arrives
- Make sure the surface is clean and as dry as possible
- Cover the door to frame gap, the threshold and the frame to wall joint
- Overlap each strip so there are no channels for water to follow
- Seal letterboxes, keyholes and cat flaps too
Remember you will need another way out of the house if the main door is taped from the outside.
Better ways to protect your home from flooding
The research also found that demountable barriers offered the highest protection when correctly fitted. A layered approach, where each part of the home is covered by the right product, will always outperform a single quick fix.
Door flood barriers
A purpose-made door barrier gives a far more reliable seal than tape, and can be fitted quickly when a flood warning comes in. The Floodshield barrier clips to the outside face of the door frame by hand, with no tools or permanent fixings, and comes in six widths for inward opening doors.
Anti-flood air bricks
Air bricks are one of the most overlooked flood routes into a home, and tape will not protect them. A self-closing air brick replaces a standard clay air brick, ventilates normally day to day, and seals automatically as floodwater rises. Nobody needs to be at home for it to work.
Sandbag alternatives
If you want something to divert or hold back low level water at gates, garages or driveways, HydroSacks and HydroSnakes are a lighter, cleaner alternative to sandbags. They weigh under 500g dry, store flat, and swell to around 20kg when activated in clean water. They work best alongside a door barrier rather than instead of one.
A pump to deal with seepage
No barrier, tape or sandbag is completely watertight. Some water will usually seep past, and it needs to go somewhere. A puddle pump can remove that water from behind a barrier or inside the property, down to just a few millimetres.
The FloodMate kit combines a pump, hoses and HydroSacks in one carry case, so everything is ready when you need it.
Common mistakes when protecting a home from flooding
- Relying on one product, such as tape or sandbags, to protect the whole property
- Forgetting air bricks, which can let in large volumes of water
- Waiting until the flood warning to buy equipment, when stock and delivery times are tight
- Having no way to remove water that gets past the defences
- Not practising fitting barriers before they are needed
If your home is at higher risk, or you are unsure which routes water could take into your property, a professional property flood resilience survey will identify the right measures.
Conclusion
The new research shows that duct tape can dramatically cut the water coming through a front door, and it is a cheap backup worth having. But it is temporary, it depends on good conditions, and it only protects one route into your home.
For reliable protection, combine a door barrier, anti-flood air bricks, a sandbag alternative and a pump to clear any seepage. Check your flood risk, sign up for flood warnings, and put your equipment in place before you need it.
