Bomanite Pervious Concrete Systems

Project Description and Brief

The National Trust owned property, Nostell Priory, situated 7 miles from Wakefield, in the North of England, is like many other stately homes throughout the country today – it relies upon gate receipts and proceeds from functions to finance the maintenance of the buildings and its grounds and estates.

It had become apparent in recent years that the influx of cars for the many functions was creating a problem in itself. With a limited macadam area available for parking, the visitors were directed on to the grass verges adjacent to the approach road to the Priory. The combination of haphazard parking and poor natural drainage had conceived unsightly scars on the natural grassland with visitors having to tread through wheel ruts to attend restaurant functions. In order to overcome the problem by providing permanent hard standings, the Estate Manager was faced with a number of problems:

1. The verges formed part of the vista to the Grade 1 Listed Priory; therefore, any system of surfacing used must be able to blend with the surrounding landscape, particularly when not in use.
2. The vista itself is used for field events such as motor spectaculars and country fairs. There would be a likelihood therefore that the verges would be subjected to loadings considerably in excess of normal car weights.
3. The grasslands were open to grazing by the Estate sheep; therefore, any surface adopted must not be injurious to the animals.
4. In order to obtain full benefit from the new parking area, the required method of parking should be clearly shown.
5. The tar macadam entrance road was laid with falls away from the centre of the road; therefore, the verges would be subjected to surface water run-off. As no existing water drainage system was available, any new surfacing must have self-draining capabilities.
6. The car parking system should provide a cost-effective alternative to traditional macadam surfacing.

Project Specification

An area of 800 m² was excavated to reduce levels, including the removal of excessive undulation in the existing ground.

After laying the 150mm thick layer of blinded Clause 803 Type 1 sub-base, GRASSCRETE GC2 (150mm thick) insitu surfacing was laid. Utilising the ‘long strip’ pouring conditions, Grass Concrete’s operatives were able to carry out the 70 m³ pour in three days.

In order to denote the required parking bays, integral solid strips of concrete 200mm wide were incorporated at 2.40 metre intervals. After burning out of the former tops, soiling and seeding, the solid strips provided a clear definition whilst still maintaining the theme of natural grassed areas.

The car park now provided parking for 70 vehicles. The GRASSCRETE system provides a continuously linked concrete surface for ease of walking. When not in use, the area becomes grazing land for sheep that are equally ‘at home’ on the surface.



Nostell, Wakefield, West Yorkshire


The Right Honourable Lord St Oswald


Chantry Contractors Limited




800 m²


GRASSCRETE GC2 (150mm thick)