The Gelder Group was originally established in 1988 as a two man operation trading as SP Gelder Builders. As the firm's reputation for quality workmanship grew, it was not long before the firm started to employ additional labour to cope with the demand for its services. For the next 5 years the firm undertook a wide range of work including individual houses and small developments in the local area. In 1993, the firm incorporated to Gelder Ltd and traded as Gelder Construction. At the same time, the company undertook its most challenging and largest contract since its inception, the conversion of a dilapidated old farm house, which had historically been a coaching inn, into an award winning Guest House and 12 new properties. In May 1995, approval was given to convert a group of old farm buildings into offices, stores and workshop for Gelder Ltd.

The following year, the company embarked on its largest housing development, consisting of 47 new homes, for which it would later be presented with an award at the British House Builder of the Year awards at the Park Lane Hilton hotel in London. The company moved into the renovated offices on Tillbridge Lane, Sturton by Stow in the spring of 1997 and had a formal opening in October 1997. A year later, the company was awarded with the Rural Development Commission's "Redundant Building" award for the quality of the renovation.  Over the next two years Gelder Ltd grew significantly, gaining a reputation for quality and service in many different sectors of the industry. In 1999, the company's turnover had grown to £5m and it had 80 employees.

In 2000, additional offices were added to the existing in order to cope with the increase in staffing infrastructure required to grow and manage the business properly. Within two years turnover had doubled to £10m and the number of Gelder employees had increased by 50% to 120. To reflect the significant growth in the company and the diversity of the building works undertaken, in January 2004, it changed its principle trading name to Gelder Group. Also in January 2004, planning permission was passed to further extend the Group's Headquarters by around 50%, adding an additional 17 new offices and 2000 square feet of secure stores and garaging facilities.  This £650,00 project was completed in 2005 and on 4th October 2005 the Group welcomed His Royal Highness The Duke of Gloucester KG GCVO to carry out an official opening ceremony.

By the end of 2005 turnover had grown to over £16 million and staff number increased to over 160.  Demand from several clients for it to increase its trading area led it to open its first regional office in January 2006, a 3600 square foot unit located just off the M1 at Barlborough. January 2006 also brought a change in the senior management of the company with the creation of a business development team made up of 10% of the Group's key employees.  One of its first announcements was a plan to grow the Group's turnover to 40m and publish and employee manual for every employee. Orders, employee figures and turnover continued to increase throughout 2006 and in 2007 employee figures passed 250 for the first time.  2007 also saw the Group purchase a 17,500 square foot former RAF warehouse and office complex on a new 2.5 acre site at Dunholme.  Out of this facility the Group created a new company, Greentech Management Services LLP.  Tasked with the responsibility of dealing with all waste produced by the Group a waste transfer licence was obtained and the Group's first skip lorry was purchased.  By 2008 80% of all waste produced by the Group was being recycled.

In November 2007 the 1 acre lake, the centre piece of the Group's 13acre environmental project to the rear of the head office was completed.  The project includes a 55,000 litre grey water system, 3000 tress, 3 large reed beds and a wind turbine.  It is calculated that over the schemes life cycle it will remove from the atmosphere 1050 tonnes of C02 annually - completely off setting the company's carbon footprint. November 2007 also saw the Group purchase River Cottage, a complex adjacent to the head office site that included a 5 bedroom farmhouse, 6 acres of land and a collection of redundant outbuildings.  An announcement was made to apply for planning permission to convert this complex into further offices and what is now the Gelder Groups Training Academy. By 2008 staff numbers increased to 300 and turnover had risen to £25 million and the company opened its 3rd regional office located at Kettering.  This new office extended the Gelder Group's trading area across the midlands, bringing it in to contact with a potential 10 million new customers.