Ground Gas Protection Sunderland
Membrane Verification Experts

UK is facing a rising problem from harmful, naturally occurring ground gases and vapours. To protect both the structure and its users, it is crucial that ground gases are identified and managed.

Gases that may be present on a site can be naturally occurring or they may be as a result of its historical use.

The naturally occurring gases methane is carbon dioxide, nitrogen, and radon. However, these gases can also be found in soil in elevated concentrations relative with normal atmospheric gasses.

Sites whose previous use was as a landfill, heavy industrial use, or where petrol, oil or solvents may have spilled can also generate hazardous gases such as methane, carbon dioxide, volatile organic compounds (VOCs) such as benzene and trace gas components such as hydrogen sulphide and carbon monoxide.

All of the above gases and vapours can have a variety properties such as being toxic, asphyxiating and flammable. They can also react chemically with concrete and plastic building materials, which could affect the structural integrity of the buildings. They can get into buildings and other structures at ground level.

These are the different types of gases


Radon, carbon dioxide and methane gasses, as well as VOCs (Volatile Organic compounds such as hydrocarbons), pose a danger to your health. Therefore, new constructions must use the appropriate materials to keep them out.

An independent ‘Gas protector verification plan’ is required in accordance with CIRIA C735. A robust design and construction process should then be followed to install the gas protection measures and the requirements of ‘verification plan’ implemented. After the construction has been verified, it is time to prepare handover documentation. This document should outline any additional measures that may be required, such as those necessary for preventing damage or during operation and maintenance.

Specialist advice is highly recommended during the assessment and risk assessment phases of ground gas data. Below are some of the key documents to be aware of and refer to:

BS8485:2015 + A1 2019 provides recommendations on ground gas site characterisation and the choice of solutions for the design of integral gas protective measures for new buildings to prevent the entry of carbon dioxide and methane and provide a safe internal environment. This process can be used to show that the risks posed due to the actual or potential presence of methane and carbon dioxide have been addressed.

Leading experts in ground gas membrane installation inspection and integrity testing in Sunderland and across the North East

How does ground gas happen?

Both brownfield sites and greenfield sites may be susceptible to the formation of harmful ground gases. Some gases are found naturally in the ground and others are caused by human activities such as mining, dumping, landfilling, and mining. These and other activities have created an environment where ground gasses can build up. People who live or work in buildings with high levels of ground gas can be exposed to health hazards from the harmful gases.

Why has ground gas become such a problem

Ground gases weren’t considered to be a threat to buildings and users in the past. Due to increasing demand for homes, brownfield sites have seen an increase in development. This is because it is more difficult to find new land to develop. However, brownfield sites can contain soil and ground pollutants.

Because of this increased awareness, the Environment Agency developed new legislation that addresses potential ground gas problems.

It is important for you to know that potential risk factors can only been determined by an in-depth ground gas investigation. This must be done by a competent ground gas surveyor.

Ground gas risk assessment

The potential for a risk from ground gases and vapours is firstly assessed at desk stage, with ground investigation or assessment designed accordingly if risks of ground gases are identified then measurement using monitoring wells in boreholes will normally be used as part of the investigations. Existing buildings can be monitored using static measurement methods and diffusion tubes. Monitoring programs can be extended for several days or months, depending on the nature of risk.

Once the investigation is complete the assessment and interpretation of the measurement data will then identify whether there is a risk from ground gases or vapours.

Protection from below ground gasses

Ground gas protection is an extremely specialised operation. GeoShields Ground Gas specialists have the required knowledge, experience and skill levels.

Ground gas protection is often achieved by ventilation and ground membranes in construction. This provides primary and secondary protection against the ingress of gases. Foundation-based ground gas protection will not work if you are an existing homeowner. Therefore ventilation is the key. Ventilation can use a combination of natural ventilation for suspended floors, improved underfloor ventilation and the introduction of mechanical ventilation systems so that the harmful ground gases can be safely controlled and vented away from the property. In all cases validation of the construction and the installation techniques is important.

There are some situations where gases and vapours may pose risks because they are a byproduct of soil or groundwater contamination. This can be mitigated by remediating the source of contamination.

What is the potential impact of not doing anything?

It is up to you to decide whether or not you react to the discovery of possible ground gas risks. Some will impact your health, while others could affect the integrity and safety of the building. Radon can cause lung cancer. Carbon Dioxide can cause asphyxiation and can be deadly. Methane, Volatile organic compounds, and Methane can all be explosive/flammable. At levels as low as 5%, methane can become flammable.

The property may be deemed too dangerous for mortgage lenders.

What is Ground Gas Membrane?

Ground gases are dangerous and buildings need to be protected. This protects the structure’s integrity as well as anyone inside it. Protection is usually in the for of a ground gas membrane.

Ground gas protection membranes are often made of polymers, but may also contain other materials such as aluminium. They are lightweight, flexible, and easily formable. They are designed to stop the gas flowing from the ground and into the building.

Leading experts in ground gas membrane installation inspection and integrity testing in Sunderland and across the North East