The company was founded in 1992 by Paris Natar, who sold his controlling stake in the business to Barclays Private Equity in a deal worth £85m in 2007.
In 2011, Barclays sold its private equity arm in a management buy-out which re-launched as Equistone.
Last year, Equistone lost control of the business and Gardman went in a debt-for-equity swap to a consortium led by Goldman Sachs, TPG and backed by Barclays and Lloyds.
Gardman has hired advisers at corporate finance firm Catalyst to manage the sale process, according to the Telegraph.
Meanwhile, the company is developing sales with Klondyke, Hillier and Choice, but is pulling out of B&Q.