Type 1 Aggregates

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Type 1 aggregates are the most widely used approved sub-base in the construction sector. Typically made up of crushed rock, gravel, or recycled concrete, they are used as a base layer for roads, paths, and buildings. Type 1 aggregates are typically characterised by their large particle size and angular shape, which endows them with impressive compaction properties and a high load-bearing capacity. They also make for an effective bulk filling and levelling material.

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Type 1 aggregates, also known as "primary aggregates," are an essential component in the construction industry. 

The term that unifies these forms of aggregates is associated with the Ministry of Transport (MOT). All aggregates labelled as Type 1 MOT are certified for use in both public and private construction projects, particularly in the building of highways and pavements. 

Known for its ability to compact effectively, Type 1 MOT serves as a dependable foundation for a wide range of construction endeavours. While not mandatory for personal groundworks, the MOT's stamp of approval guarantees that Type 1 aggregates possess the necessary characteristics to furnish a secure and stable base layer for your construction project.

MOT Type 1 Sub Base

MOT Type 1 aggregate is an approved granulated sub-base product that is manufactured using recycled crushed concrete and rubble. 

This hardwearing crushed aggregate material functions as a sub-base for a wide range of construction needs including building bases, driveways, and paving foundations. 

MOT Type 1 provides a sublayer for road surfaces and pathways, offering a smooth surface upon which to apply asphalt, concrete, shingle or block paving. 

It should be noted that a bulk bag of MOT Type 1 contains moisture, which means that the weight stated on each bag varies from shipment to shipment, however, the product quality always remains the same. 

Type 1 Aggregate Applications

Type 1 aggregates are sub-base materials relied upon in a variety of construction projects, including foundations, road building, and highway works.

Generally, Type 1 aggregates are compacted to form a solid base for the following structures:

  • Car parks
  • A filling product - trench filling, backfilling and over-site fills
  • Under products 
  • Finishing surface shingle for driveway/garden path applications
  • Base layer for road surfaces

Type 1 Aggregate Key Features

One of the key properties of type 1 aggregate is its ability to bind and compact well, which makes it an ideal material for construction. 

Let's dive a bit deeper into its key features: 

  • Both primary and recycled material can be utilised to create a Type 1 sub-base
  • Frost resistant and will suppress weeds - doubles up as a weed suppressant
  • Cost-effective solution for many construction projects
  • Easily compacted
  • Specified by the British Standards for the construction of roads and other infrastructure projects
  • Delivered in bulk bags for large project quantities

Here at Materials Market, we stock a full range of sand and aggregates as well as decorative aggregates to assist you in any construction project. 

Frequently Asked Type 1 Aggregates Questions

What Is The Difference between Type 1 and Type 2 Aggregate?

Type 1 and Type 2 aggregate are different classifications of construction aggregate.

Type 1 aggregate, also known as "DTp1" or "DTp Type 1," is a granular material that is typically made from crushed rock, such as limestone, granite, or gritstone. It is typically used in road construction and other transport infrastructure, also serving as a sturdy sub-base layer for building foundations.

Type 2 aggregate is a material that is typically made from crushed rock, but is of a lower quality than Type 1. Type 1 aggregate is considered to be of higher quality, and is used for more critical applications, while Type 2 aggregate is finer and has a higher dust content. 

How Much Area Does a Bulk Bag of Type 1 Cover?

In general, a bulk bag of MOT will cover approximately 8m2 at a depth laid of 50mm.

What Are The Primary Aggregates Used in MOT Type 1? 

  • Limestone 
  • Granite 
  • Sandstone 

Which Recycled Aggregates Are Used in MOT Type 1? 

  • Crushed Concrete
  • Crushed Glass
  • Selected other aggregates (generally brick, ceramic, etc.)

What Are Scalpings? 

Scalpings are more or less quarry waste. These small stone offcuts are removed during the screening process for larger, higher-quality rocks. 

Despite the negative connotation of being labelled as "waste," scalpings are incredibly useful for levelling out foundations due to their durability, versatility, and abundance.

Is Type 1 Good For Drainage?

While MOT Type 1 is a great sub-base material offering many benefits, it has a minor drawback in that it is not a permeable sub base material. This means that water will not pass through it easily and, if it does, it will take a much longer time to filter through. Alternatives such as granite or limestone, however, offer much better drainage properties as sub bases.

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