Volunteer-run Wallingford Museum’s plans to open an extension this year have suffered a setback following funding difficulties and the resignation of the project manager.

Work on a £400,000 timber-framed extension, the construction of which will be used to teach traditional building methods, was due to start in August, but has been postponed until autumn 2011.

The museum, a registered charity, blamed the delay on late grant applications.

Managing director Stuart Dewey, whose role is voluntary, said he was “reasonably confident” of securing a £100,000 local authority grant to add to the £50,000 already raised, although other funds were still being sought.

“Each application needs three quotes for every single piece of work and piece of equipment,” he said. “We just couldn’t get the information together in the time available.”

The launch date of the project, 21 August, which would have involved workers from The Carpenters’ Fellowship begin a “living construction”, will now be a fundraising day instead.

The project suffered another setback when its manager, a volunteer and member of the Carpenters’ Fellowship, quit in a dispute over ownership of the new annexe, which is to be held by the museum rather than made property of the town.

Dewey said he was confident of securing another project manager, an architect, soon and still hoped to get the Carpenters’ Fellowship involved.

“Our biggest concern is that this delay means we don’t lose the impetus of public support, – when we got planning permission, we had 300 letters backing us,” he added.