Mongan Contractors is an established business with over thirty years of experience in building and construction.

As South London-based builders, we use our best expertise to offer you cost effective solutions which will add value to your property, helping it to stand out from the crowd without the need for over-spending. In addition to providing skilled builders on site we offer access to independent specialists such as surveyors and designers, to help add that extra special expertise.


We pride ourselves in providing clients with a professional service, access to quality builders delivering highly skilled workmanship, and a quality finish to meet and exceed your expectations. Whatever your needs we can offer you the flexibility and experience to take on large or small projects - all completed to ensure compliance with building regulations.

We undertake all aspects of domestic construction - extensions, refurbishments, loft conversions, new roofs and windows, kitchen extensions, and refurbishment projects of all kinds involving both domestic and commercial builds.  However large or small, we will take on whatever it needs to meet your vision.

If you are looking for builders with real attention-to-detail and the ability to deliver within budget then please get in touch.

Why choose us?

  • We have over thirty years building experience and have many satisfied local customers. Indeed, the majority of our work comes from customer referrals. We have experience in all types of lofts as well as kitchen and bathroom renovations.

  • We will not compromise on materials and only use the very best and always work towards the customer's personal preference as well as within budget.

  • Customer service is at the heart of our business and we will ensure that you receive the highest level of customer attention that you ought to expect.

  • Although our specialism is in lofts, we undertake all manner of extensions and renovations. You can view our most recent portfolio, read our customers' feedback and browse our services pages on this site.

About Tom Mongan


Tom Mongan has been building all of his life, working for and then running several construction businesses in London.

From Roundstone in the Republic of Ireland, Tom has been building in the Capital for over 30 years, living the whole time in Tooting.

He has great experience of running small, dedicated teams of local builders who know their trades well and deliver projects of any complexity on time and on budget.

Always happy to chat through a project - or show off work that he's done - please give Tom a call if you have any questions.