An image of a new raw building

About Us

Seamus O Brien & Sons Builders (Castlebar) Ltd. are a Family run building contracting company based in Castlebar, Co Mayo. Seamus himself has over 40 years of experience in the construction industry and has seen the industry develop over this time into what it is today. We specialise in one-off homes, extensions and renovations of any size and complexity, residential developments, schools and other public projects. we have also delivered a sizeable portfolio of small and large-scale commercial projects.

We operate nationwide, but mainly focus on the Connaught region. With a directly employed staff of highly capable trades people and a highly proven panel of skilled subcontractors.

We are up to date with all of the latest building methods, regulations, and architectural styles while striving to deliver first class projects on time and on budget every time.

Feel free to contact us for a no obligation quote or for any friendly advice you may need at any time.





Just some of our client list

  • City Electrical Factors Ltd
  • Savannagh Securities Ltd
  • EPS Environmental Protection Services
  • Abbey Breaffy Nursing Home
  • Home store + more
  • Kelem Properties
  • Breaffy House Resort
  • K & S Developments
  • St Patricks Boys National School
  • Parke National School
  • Mayo Vocational Educational Committee
  • Board of Management Parke Community Centre Ltd.
  • Mayo County Council
  • Beckett Developments Ltd.
  • Hundreds of other private clients

Some of Our Partners

  • Quinn Associates
  • John Halligan Architects
  • SDS structural Design Solutions
  • James Langan Engineering
  • David O Malley & Associates
  • Marie Galvin Architects
  • Better Safety