Sub-base material selection
Sub-base material is produced by crushing either limestone or granite rock.
The sub-base is designed to evenly spread the load on traffic bearing areas such as pavements and roads. Made up of a load-bearing layer of aggregate, the sub-base is laid on the sub-grade layer below. It is the main loadbearing layer in the construction of roads and pavements.
The type of sub-base is extremely important for the longevity and quality of the highway. The sub-base distributes weight over a wide area, thus reducing settling of the surface. It’s the interlocking nature of the sub-base particles that distribute the weight in multiple directions instead of directly downwards.
Type 3 sub-base Open Graded SHW Clause 805
Type 3 Open Graded SHW Clause 805 sub-base is a pure crushed stone, ranging in size from 40mm down to dust, but with a reduced (not zero) fines content.
Available both as a granite or limestone, Type 3 sub-base is widely used as a sub-base material for projects where a lower fine content is required for improved drainage. These include sports pitches, equestrian centres, driveway/hard standings and roads.
Soils and stone supply Type 3 Open Graded SHW Clause 805 sub-base quarried primary aggregate to comply with Highways Agency Clause 805 (SHW Clause 805).
40MM–75MM Clean Stone
Available as either granite or limestone, this is a crushed stone with no fines that ranges in size from 40mm–75mm.
When compacted, it provides a hard-wearing and well drained sub-base for use in roads, paths, drainage ditches, sport pitches, etc.
4 – 20MM SuDS Aggregate
4 – 20mm SuDS aggregate is an ideal upper sub-base material when creating any permeable solution. In addition it provides increased void space allowing even water storage.
10 – 63MM SuDS Aggregate
10 – 63mm SuDS aggregate is an ideal lower sub-base material when creating any permeable solution.
A clean, no fines angular stone provides a 30% void space and enhanced water storage capability when laid on the sub-grade.
The material for recycled sub-bases are drawn from crushed aggregates, such as concrete, hardcore, ballast and road plannings that are removed from older sites and then recycled.
Recycled Type 3
Formerly known as Type 1 X, Type 3 uses a mix of clean, recycled aggregate. It is generally 40mm open-graded with reduced (not zero) fines, making it ideal for drainage.