Technical Articles
Specification - The key to effective cost management
Published 05 June 2019

Avoiding under-specification on UK driveways is key to achieving cost objectives in construction. Consider for example, drainage where manhole covers with inappropriate load-bearing capacities are sometimes causing installations to be revisited by developers to make repairs, costing several hundred pounds a time. 

In certain trafficking, the long term effects of undervaluing loading requirements can be easily avoided by installing a B125 (12.5T loading classification) cover as a minimum. For example, the kerb weight of a 4x4 commonly varies between 1.6 and 2.5 tonnes, depending on the model, exerting a load, when turning and braking through any one wheel of 6-10 tonnes! This is because, in extreme cases, dynamic loads apply up to 3 or 4 times the static mass of the vehicle, through a single wheel!  This thought process, also benefits scenarios where infrequent traffic – skip loaders, removal vans, waste collection lorries, etc., needs access to driveways, footpaths and grass verges. Again in this instance B125 loading class should be specified as a minimum.

Fash Shahidi of Clark-Drain comments:

“The correct choice of manhole covers can have a significant impact on house building maintenance cycles and replacement costs, but are sometimes overlooked due to slightly higher purchase price or incorrect specification. Manufacturers have a duty to educate the market so that correct choices are made by house builders, driveway specialists, subcontractors and ground workers. Furthermore, in recent years loads have risen as cars have continued to increase in weight and size. What may have been installed originally to take a driveway loading may not be sufficient to avoid a manhole cover becoming bowed, cracked or broken, today. I would encourage any contractor who is unsure of the correct choice to speak directly with their manufacturer for clarification as we are here to help and support.”

At Clark-Drain, products such as the CD 761SR KMB+R are designed specifically for driveway applications, as a result of feedback from house developers who were experiencing costly breakages.

Fully Kitemark certified to Load Class B125,  capable of bearing a 12.5T load, in line with BS EN 124:2015, Clark-Drain’s CD 761SR KMB+R access cover offers a long-lasting and sustainable driveway drainage solution.

Furthermore, for chamber depths more than 1.2m, the CD 761SR KMB+R is supplied with a reducer to convert the 450mm diameter clear opening to 350mm in accordance with Building Regulations Part H to restrict the size for health and safety reasons and deter entry (for example by children).



Why Choosing the Right Drainage and Access Specification and Design is Paramount

Choosing your drainage and access products When choosing full article >

The Great A15 debate

One of the most common queries we get as a drainage product full article >