Applicabilty and treatment of excise duty and service tax ?

Hi friends, I need Clarification related to this issues,

One of our Client, Private Limited Company Manufacture “Chimneys ”(not kitchen Chimneys)

It contain 3 Stages

1.Steel work

2.Conical Work

3. Erection

1^st and  2^nd Stages manfured  with in Factory , 3^rd  Stage was in customer place.  

Chimneys Size and Price was differ as per customer requirement.

I need clarification related to applicability of  Point of Excise duty collected , value on excise duty ( In this valuation Erection Charges in included or not ), company  supply all the matterals to job workers(Erection Group), her Service tax liablity is applicable or not?, while payment to job workers(Erection Group) TDS is liable to deducted, if yes , applicable section is 194C or 194J

Please Guide me Sir