A covenant promise, agreement or understanding in or in connection with or collateral to a contract or agreement relative to the construction, alteration, repair or maintenance of a building, structure, appurtenance and appliance, including moving, demolition and excavating connected therewith, purporting to indemnify or hold harmless the promisee against liability for damages arising out of bodily injury to persons or damage to property caused by or resulting from the sole negligence of the promisee, the promisee's agents or employees or indemnitee, is against public policy and is void and unenforceable.