Four days of testing a water-proofing membrane on a Christchurch house appears to have been a success.
A red zone house was partially coated with the membrane on Friday and the area around the house was then flooded. By Monday, minimal water had entered the house.
The Christchurch City Council's Mayoral Flood Taskforce says it's glad Blue Barrier has worked as it provides an option for residents living in flood-affected homes.
The membrane used costs between $15,000 and $20,000 to apply to a home.
Aecom engineer Stuart Sandy said the company was working on the basis that if it could protect a red zone house, it could protect any house.
"This house has kind of been used as a worst-case scenario. There were a lot of rotten timbers around the outside of the house and inside the house, so we've worked on the basis that if we can protect this one, then the rest of them should be a bit easier."
Mr Sandy said water seeped in to the foundations, but was dealt with by pumps as planned.
He is glad the method had been proven to work and said it was up to affected landowners and the council to decide if they would use it.
But Diane Shannon, a resident of flood-prone Carrick Street, said given the cost of repairing existing flood damage, using the membrane method is very expensive.
The taskforce will report its results to the council.