Self-Build PassivHaus HDD Case Study



Case Study – Trenchless Technologies For Mains Installations at Self-Build PassivHaus Eco House New Build, at an environmentally sensitive site.

As a leading provider of Trenchless Technologies throughout the South of the UK, K M Plant Hire & Groundworks Ltd. were approached by an Architect, to facilitate a Trenchless Technology (‘No-Dig’) solution, in respect of the installation of Mains Utility Services to a Self-Build PassivHaus (Eco-House) new build project.

Following consultations, K M Plant were engaged by the Client, to facilitate the underground installation of  Utilities connections, with the minimum possible risk of disturbing the existing tree root structure, protected within the scope of Root Protection Areas (‘RPA’), following the methodological recommendations, recommended within an Arboricultral Report, stipulating the utilisation of ‘No-Dig’ Trenchless Technology.  It was identified that the most effective and efficient method was to use Horizontal Directional Drilling (‘HDD’), which allowed K M Plant to install underground Utilities with minimal risk of disturbance to the surface and root structure of the established trees, at the environmentally sensitive New Build site location.


A minimal excavation footprint required to install underground utilities when utilising Trenchless Technologies such as Horizontal Directional Drilling (‘HDD’), in comparison to conventional ‘Open-Cut’ Trenching. The application of Horizontal Directional Drilling (‘HDD’), has proven particularly successful as a method of conducting underground Utility Mains installations in environmentally sensitive sites. Therefore, it is particularly pertinent in respect of sites such as this where an RPA exists. Horizontal Directional Drilling also provides the additional health and safety benefits of minimising required open excavations, with a potential reduction in trench collapse risk and exposure. This modern technique is becoming increasingly favoured due to its low environmental impact and significant reduction in works duration. In respect of this, the Client can potentially enjoy considerable time and cost savings, up to approximately 66%, by employing the use of Trenchless Technology in their project.

The K M Plant Commercial Team liaised closely with the Client to consult on applicable Best Practice, and to discuss, offer and agree the optimum value solutions throughout the work. Mr. Andrew Bradley, the Head of Commercial at K M Plant advised: "K M Plant focussed on developing the most efficient methodology to deliver optimum value for the Client, utilising innovative measures and Best Practice methodologies, to meet all required specificational and Legislative requirements, to an agreed target cost and within the desired timeframe." 

As a highly responsible Specialist Contractor, K M Plant engaged Arboricultral Consultant Mr. Bruce Macfarlane, MArbor A, P Dip Arb (RFS), to prepare a Site Specific Risk Assessment and Method Statements. Mr. Macfarlane stated: “It is refreshing to be involved with a Civil Engineering company that takes its environmental responsibilities seriously.  The Clandown project only involved Drilling a short distance under the root plates of two mature trees.  By getting arboricultural advice early on in the scheme ensures that the works could progress knowing that both the Local Planning Authority, the Architect and the Client are happy that both the working methodologies and the appropriate paperwork are following industry best practice.”

Two protected Sycamore trees were only 6.5 metres apart and have deep roots, which are subject to Root Protection Areas (RPA).  The Arboricultral Report advised that it was not permitted to alter, move or damage the roots. Therefore, the most effective and efficient method, was to go under the root zone using Trenchless Technology in the form of Horizontal Directional Drilling.

Mr. Craig Tinton, the Senior Construction Manager at K M Plant advised: "K M Plant's highly experienced team of Trenchless Technology specialist Technicians, were able to achieve an efficient installation at the Site that presented some considerable Environmental and Geotechnical challenges, through the utilisation of leading-edge Trenchless Technology techniques, such as Horizontal Directional Drilling." 

The PassivHaus style of this New Build, Eco House project, is currently the fastest growing energy performance standard, designed to be environmentally neutral, and with currently with over 30,000 buildings constructed to date. The principles derive from the concept of a building with excellent thermal efficiency, exceptional airtightness and with an intelligent mechanical heating and ventilation management system, to allow for thermal comfort. The PassivHaus components do tend to be more expensive than conventional components, however the energy consumption related cost savings, generally offset the additional cost of construction, whilst also providing a reduction in the carbon footprint. Therefore, all additional initial expenditure should facilitate substantial savings achieved throughout the lifespan of the property.

Through the delivery of the required Utility Mains Laying via Trenchless Technology, with a sympathetic consideration for the immediate environment, the Client enjoyed not only a fully Best Practice compliant delivery of the works with the appropriate care and attention applied to the protected tree roots and indigenous wildlife at the Site, but the Client also enjoyed a significant cost and works duration saving over the traditional Open-Cut methodologies, along with minimised inconvenience to other residents immediately proximate to the Site, by also avoiding the need for open Trench protection and the additional safety fencing.

K M Plant is frequently engaged by environmentally responsible, proactive and forward-thinking Developers, Contractors, Architects, Professional Advisors and Representatives, seeking the services of a high quality reputable company based in the UK, in respect of the provision of specialist Trenchless Technologies (where mains pipelines and cables are laid underground, using specialist techniques and equipment), for Mains Connections, New Supplies, Pipelines, Cables and Sewers, etc.

K M Plant is a leading Trenchless Technologies specialist that utilises innovative technologies to reduce cost and works duration for the Client, and any subsequent potential inconveniences to the public. K M Plant can also provide specialist Diversion works, avoiding supply interruptions, to minimise public inconvenience, and limit or avoid exposure to potentially expensive delays, charges, fines and compensation events, also ensuring the immediate adjoining users of the common supply, are not without supply.  Contact K M Plant for an initial consultation, to see how by engaging our services, K M Plant can save your organisation time, money and inconvenience. 



Contact the Developer Services team direct on 0203 146 9560 to discuss how K M Plant can assist with your specific requirements.