Respected Sir,
The Works contract includes construction of building as the definition of Works contract is as follows "means a contract wherein transfer of property in goods involved in the execution of such contract is leviable to tax as sale of goods and such contract is for the purpose of carrying out construction, erection, commissioning, installation, completion, fitting out, repair, maintenance, renovation, alteration of any movable or immovable property or for carrying out any other similar activity or a part thereof in relation to such property"
If you are claiming abatement under NN 26/2012 the value should include land cost also, then the abatement of 75% or 70% can be claimed not when only construction activity carried out then the taxable value should be 40% as per valuation rules.