What lurks beneath?

Gas and water are two potential below-ground problems that need to be sorted out before a project gets under way.

Radon gas is formed by the radioactive decay of uranium in rocks and soils. It’s a threat to the health of the occupants of buildings into which it seeps. Fortunately, maps are available indicating high-risk areas and there are established procedures for measuring levels of the gas and safeguarding people from harm.

Methane (a low-toxicity asphyxiant) and carbon dioxide (a high-toxicity asphyxiant) can be problems close to landfill sites and areas where old woodlands have been left to decay. Again, with the right investigations and protection measures, any significant risk can be removed.

Then there’s the question of whether the location of a proposed building could be subject to flooding. With the proper maps and a good desk study, any threat can be assessed and, if building work proceeds, steps can be taken to minimise the risk or design the structure in such a way that any damage from flooding is limited.

Attending to all these matters with the aid of experts can avoid a host of problems, from physical danger to difficulties over insurance cover and eventual resale. Your engineer should address those issues as part of the design and record the measures taken, if any, as part of their design statement.