Report Surveys & Investigations

Allowable movement

In the UK we use the “Burland Scale” to classify cracking to buildings. Cracking can look concerning and the Burland scale gives a guidance. Extract from The Institution of Structural Engineers “Subsidence of Low-Rise Buildings”. Table 6.2 Classification of visible damage to walls with particular reference to type of repair, and rectification consideration.

Building Investigations

Investigations into existing buildings, their defects and current condition is our practice’s core activity, along with building design. With our extensive knowledge of construction techniques combined with continuous refurbishment projects, we are perfectly placed to understand problems. There are numerous types of investigations and surveys completed.

Building Defect Surveys

Croft Structural Engineers is able to survey all building materials commonly found. Barclays Bank Surveyors (Atis Real) utilise our knowledge to undertake structural surveys. Typically, these are on occasions where their Building Surveyors require our Structural expertise. Croft Structural Engineers is able to organise and undertake a variety of investigations. Concrete suffers from the polluted environment and numerous tests can be undertaken to determine its current suitability. “Regent Street Syndrome” is often seen. This is where steelwork in 1920 buildings corrode, forcing the expansive force to crack the masonry facades.

RAAC Survey

RAAC stands for Reinforced Autoclaved Aerated Concrete. It emerged as a lightweight alternative to traditional concrete during the construction boom of the 1950s to the 1990s. RAAC was predominantly used in the public sector, notably for schools and hospitals. Filled with air bubbles, RAAC boasts reduced density, rending it cost-effective and lighter than conventional concrete.  However, it has a shorter lifespan of around 30 years and is less durable than traditional reinforced concrete. Its structural behavior differs significantly from standard concrete, and it is susceptible to structural failure when exposed to moisture. The bubbles in RAAC can allow water to enter the material, leading to decay, rust, and weakening of any rebar reinforcing it. Croft Structural + Civil is well placed to help building owners with this process and provide RAAC plank surveys.

Mortgage Surveys

Croft Structural Engineers are happy to undertake an appraisal to support a mortgage or simply for peace of mind. We are often called at the last minute, just days before exchange. It is our aim to attend the site and return the survey with 4 days of appointment. Our reports are completed by a Chartered Engineer and the format is specific to the property. We do not roll out a list of generic defects with a few lines of specific information at the bottom of the page. Every item will be about the property and its defects. Where possible, we will suggest the repairs required along with our anticipated costs.

Subsidence & Movement Surveys

All buildings require maintenance to ensure their longevity. London has an ageing building stock which has suffered over the years.
By far our most common call to the practice is domestic clients calling about concerns of movement to their house. It is easy for us to arrange for an Engineer to visit the property and provide an opinion on the cause of the movement.

For a more detailed inspection Croft has now started to employ 3D laser surveys.

The surveys are known as Cloud Point Surveys, and can survey the external envelope of a building in a morning and provide details of how much the walls are leaning and bowing. They are so much quicker than erecting a scaffold and so much more accurate than a plumb bob in the wind.

Drainage Surveys

Failed drains can cause unseen havoc to foundations. To check and inspect existing drawings Croft can arrange drainage surveys to be undertaken. After the survey you will provided with a written report and an electronic video of your drains (one not to put on during Saturday movie night with your friends!).

Dimension Surveys

The Staff of Croft Structural+ Civil have the technical ability to undertake building and land surveys. It is not one of the practice’s core services. We can help organise these surveys with sub consultants.

Building Failures

Thankfully on rare occurrences, Croft Structural + Civil are called in at short notice to inspect dangerous structures. Our large knowledge base of historic buildings allows us to quickly assess buildings and determine what further investigations and works are required.

Soil Investigations

With our knowledge in Geotechnics & Geophysics, Croft has the capability to provide specifications and arrange soil investigations. These investigations are carried out by specialist contractors who can complete a range of services including:

• Hydrology, Soil strengths & parameters
• Geophysical ground radar, Chemical analysis & Contamination testing.

Hydrogeological Surveys

With our work on basements we have found it necessary to develop our knowledge on Hydrogeology. This is the flow of water below ground. We now commonly provide reports on the expected hydrogeology and expected water flows below ground and how a new development may impact upon that. The reports are signed and produced by a Chartered Hydrogeologist.