How much for Damp Proofing?

[financialwizard]

I am currently selling my house. It has been dragging on for months. Finally got to the day where we were supposed to exchange and the buyers now want a damp report. The guy went out today and told the EA that when the french doors at the back of the property were installed the builder did not put adequate damp course up the wall. I bought the house with the doors already done and knew nothing about this.

Anyway, the work that needs doing is to take off the plaster board (about 12 inches by 8 inches) put the damp course in, put the plaster board back on, replaster and decorate.

I have never had work like this done before so was wondering of anyone who has can give me an idea of cost.

I am waiting for the EA to come back and tell me but I have no idea how long that will take and I would like an idea in case I need to brace myself.

We were quoted 350 recently for a ground floor flat.

Tiredness - the EA arranged it, and it needed doing apparently.

Thanks gallicgirl. Maybe I won't fall off of my chair after all!

Argh I posted again and obviously failed thanks to screaming toddler.

Anyway, that 350 was for damp proofing the whole flat. For just that bit of plastering I'd expect to pay maybe 50-80. Not sure what just a wee bit of damp proof would be.