Soil Stack Design

Having pioneered the development of solvent-weld systems, Terrain Soil & Waste products represent the industry benchmark for quality, installation, flexibility and product innovation backed by the highest levels of customer service. 


  • Industry leading range of solvent and Push-Fits oil and waste solutions 
  • Unique products offer unrivalled installation options
  • High quality stack design,  finish and colour to match all systems
  • Suitable for all types of commercial and domestic installations 
  • Extensive technical experience to support and advise on all aspects of design and installation 
  • Fully accredited product systems 


Everything is considered during soil stack design, such as the building regulations requirements, thermal expansion, working temperature, branch connections, chemical discharge, access, fire spread and pipe support. Soil stack ventilation is also key. The flow of air within the drainage stack pipework system is equally as important as the flow of water in maintaining a safe and hygienic drainage system. The unsteady (transient) flow of water through the pipework creates both positive and negative air fluctuations which can compromise water trap seals.

To maintain a state of equilibrium in a drainage stack, it is necessary to respond to an increase or decrease in air pressure: this response time is critical for protecting trap water seals. The installation of a secondary ventilation stack and branch pipework system has been incorporated into drainage design and installations to overcome transient air fluctuations.

Terrain systems include an extensive range of innovative soil stack design & waste drainage products for commercial, industrial, housing and public sector developments, all built on the strength of our Terrain brand.


As you would expect from a market leader our products come with all relevant standards including: 


Manufacturing Standards 

  • BS 5255:1989 Specification for Thermoplastics Waste Pipe and Fittings 
  • BS 4514:2001 PVC Soil and Ventilation Pipes, Fittings and Accessories 
  • BS EN 1329:2000 Plastic Piping Systems for Soil and Waste Discharge 
  • BS EN 1566:2000 Plastic Piping Systems for Soil and Waste Discharge (Chlorinated) 
  • BS EN 12380 A1 Air Admittance Valve
  • BS EN 12380 A1 Air Admittance Valve (Pleura System) 
  • BS EN 1366-3 Terrain Firetrap Sleeves and Collars 


Quality Management Systems Standards

  • EN ISO 9001:2008 Management System
  • EN ISO14001:2004 Management System
  • BS OHSAS 18001:2007 Management System
  • PASS 99:2006 Integrated Management Registration