Beck says that adjudicator's decision made last year was wrong.
Chessington company Beck Interiors is suing Hudson Engineering Services for damages of up to £50,000.
Beck is asking the High Court in London to rule that an adjudicator's decision originally made on November 1 last year and amended a week later, is wrong.
Beck also seeks a declaration that it does not owe any money to Hudson, of Garth Road, Morden, Surrey, under a sub contract, and is also seeking damages limited to £50,000.