Samantha Sweeney, 45, was stunned to learn 90sq ft overhangs the shared driveway between their houses.
Samantha, an insurance worker, says Persimmon Homes did not point out the boundary line quirk when she bought the semi in 2006.
She said: “It’s disgusting. Persimmon should have sorted it then. The fact they also recommended the solicitor they now claim ‘missed’ this stinks.
“Persimmon have sold the land to my neighbour, then built my house and sold that portion of the land again. That’s not on.”
The split-ownership is shown in Land Registry documents and emerged when she tried to sell the £375,000 house last May.
Samantha says it has already cost her a buyer
She bought the four-bed new-build in Colchester, Essex, in 2006 for £285,000. The conveyancers, David Lowe and Co., of Broxbourne, Herts, were recommended by Persimmon and regulated by the Council for Licensed Conveyancers.