Mars Builders and Building Contractors
The Elms,
Gun Road,
Hertfordshire (Herts),
Tel : 01438 812949 Mobile : 07956 503162
E-mail :

MARS Builders provide Building, Groundwork and Demolition Services throughout Hertfordshire (Herts), Welwyn, Stevenage, St Albans, Harpenden, Knebworth, Hertford, Hatfield, Welwyn Garden City, Potters Bar, Brookmans Park and surrounding areas

Mars Builders - New house builders, domestic extensions, alterations and all types of building works

Based in Knebworth, Herts, Mars Building Contractors is an established, family run business, with over 25 years building experience.

We work mainly in the Hertfordshire (Herts) area with most of our contracts being in Welwyn, Stevenage, St Albans, Hatfield, Harpenden, Knebworth, Hertford, Welwyn Garden City, Potters Bar, Brookmans Park.

The majority of our building work has come through recommendation, which has enabled us to build a very good customer base, generating new and repeat business.

New House Builds

New House build

Working with property developer or private house owners, our architects or your own, we pride ourselves in offering a full and efficient service on all new house build projects.

Domestic Extensions


Extending or making alterations and improvements to your house enables you to maximizes and personalize your property to its fullest potential.

Loft Conversions

Loft Conversions

Mars Building Contractors are able to offer a full Loft Conversion service, from an initial no obligation consultation to designing with our architect and then project management and construction of your loft from start to finish.

Groundwork and Demolition

Over the years we have worked in partnership with Welwyn Services enabling us to carry out extensive groundwork and demolition contracts, varying in size, working on both domestic and commercial projects.

We are able to offer:
Demolition and site clearance,
Internal demolition and stripping out,
Bulk excavation and groundworks,
Micro piling,
Grab lorry hire,
Plant hire.

Latest News

Mars Win Awards

Mars Building Contractors are very proud to have been presented with a highly commended award at the 2012 Chilterns Building Design awards and a Highly commended Design Award at the 2012 Aylesbury Vale District Council Awards for the extension, renovation and conversion of The old Brewery House in Ivinghoe. The Brewery House built in 1790 […]


Latest from Blog

New year for Mars Building Ltd

It’s 2017 and Mars Building Ltd is pushing ahead, last year we had the wonderful experience of working on BBC 1’s DIY SOS and made some great new friends, but more importantly helped a really deserving family, who are now really enjoying their new home and new life together!! The show should be aired in […]


Looking for a reliable builder - give Mark a ring now for a chat or arrange a free quotation …
Tel : 01438 812949 Mobile : 07956 503162
E-mail :

Our Customer Satisfaction Promise:

Mars Builders and Building Contractors has been built on reputation; we know that we are only as good as our last job so with our building projects you get:

No hidden extras
When we price a building job, we provide a detailed quotation, so you will know exactly what is and what is not included. This means there is no question of any hidden extras!

Quality assured
All our builders and tradesmen are fully qualified and experienced. They have worked together for many years.

Everyone works to the same high standards, with the same aim - to achieve the best possible results with complete customer satisfaction.

Service you can rely on
We know that once your house and life have been disrupted by the start of building work, the last thing you want is for nothing to happen for days or even weeks on end. With Mars Builders this does not happen.

We only take on building projects which we are sure we can cope with, which ensures that we can achieve full continuity of work on all our contracts.