Work contract under service tax

I wish to know whether the following two cases are covered under Work Contract for the purpose of Service Tax

1. Fencing the boundary walls of Company.

2. Construction of stand with posters, lightings etc

In both the cases, vendor is not charging service tax in their bills. However, under Reverse Charge, Co is liable for its share of service tax. What is the Receiver's liability under Work Contract.

Thanks.