Technical Survey Terms: FAQs

Our most frequently asked questions about commercial building surveying terms.

Our FAQs are constantly being updated, but please contact our professional, knowledgeable team today if the answer to your question is not listed below!

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Technical Terms

What is Subsidence?

Subsidence is the sinking of an area of ground. If this is below a building, it can lead to structural movement. This movement can manifest in cracking, distortion and even foundation damage and collapse. Our guide to subsidence in commercial buildings covers the issue in more detail, from signs and causes to remedial works.

What is Damp?

Damp is the excessive build up of water in a building. It can arise from internal or external sources of moisture, and can result in damage to decorative finishes, fixtures and fittings, plaster, masonry, metal and mortar. In minor cases it can be unsightly and cause a musty odour; in more severe cases it can promote the growth of harmful mould, and even undermine the structural integrity of a building.

What is Fire Separation?

Fire separation compartmentalises a building to prevent and slow the spread of fire, flames and smoke. It is used to protect escape routes, secure high risk areas, and reduce the extent of damage should a fire occur. Fire separating elements are a critical aspect of building safety and need to be maintained in their entirety to remain effective.

What is Wood Wool Slab?

Wood wool slab is a deleterious material, used as formwork for in situ concrete in the 1960s and 1970s. Because it compresses easily and unevenly, gaps easily formed in the concrete unless it was laid very carefully; these gaps can allow water to reach and corrode steel reinforcements.

What is Lath and Plaster?

Lath and plaster is a plasterwork technique that was used between the 1700s and mid-20th Century. It consists of wooden strips that are nailed to joists, and then covered with layers of plaster. When in good condition there is no need for replacement, but damaged lath and plaster ceilings are at risk of failure and collapse of the material.

What is Cut Edge Corrosion?

Cut edge corrosion is the damage and breakdown of material at the cut edge of a metal sheet. It is commonly seen at the edges of metal profile roofs, but can also affect metal canopies and cladding sheets.

What is an Energy Performance Certificate (EPC)?

An EPC, or ‘energy performance certificate’ is the energy rating assessment of a building.

The EPC will take several factors into account, including the fabric of the building, how the property is used, and the heating, lighting and ventilation systems in place.

EPCs use a scale from A to G, with A being the most efficient and G these least. Once issued, they are valid for 10 years, unless major changes are made to the property before the EPC expiry. Once the 10-year period has expired, a new EPC will be needed when the property is next sold, let or substantially modified.

Most buildings are legally required to have an EPC, but there are a few exemptions. Listing exempts a building if complying with MEES requirements would unacceptably alter its appearance or character.

Places of worship, industrial sites, workshops, and certain agricultural buildings are exempt from EPCs, as is most furnished holiday accommodation, and temporary buildings.

Small, standalone buildings with a total useful floor area of under 50m² do not need EPCs, not do most buildings that are going to be demolished.

What is the Minimum Energy Efficiency Standard (MEES)?

MEES is the minimum level of energy efficiency required by a property, as stipulated by the government. It applies to any properties that are legally required to have an EPC.

Since 1 April 2023, MEES regulations have stipulated that commercial landlords cannot enter into new rental contracts on any commercial properties unless those properties have an EPC rating of at least E. This applies even where tenancy has remained the same.