There have been several incidences over the years where structural movement monitoring would have come in very useful. In November 2020, two West London townhouses collapsed during construction work that was going on inside them; considering that less than a year before this, a similar townhouse on the same terrace sold for more than £15,000,000 the reparation costs for this collapse would have been substantial. Costs that could have been avoided through a relatively simple and cheap building movement monitoring system.
Clearly, this error could have ended up costing far more than two historic 18th Century Chelsea townhouses and a hefty insurance claim, but for the fact that the buildings collapsed late at night, while the street was relatively empty and there was no one inside the two buildings.
Unfortunately, this is not the first time this sort of incident has happened. In April 2017 a £1M house collapsed during basement construction work in Derwent Avenue, Kingston; and in November 2015 an end of terrace property in SW London collapsed during basement extension building work that was taking place inside.
Monitoring Building Movement
The purpose here is to answer the question we frequently get asked at South East Site Engineers; what is the point of monitoring our building work?
Like everything else on the planet, buildings are constantly moving; this movement may be exaggerated during excessive vibration from road traffic, trainlines, or tunnels, and of course material movement during construction work; especially basement construction work.
When underpinning an existing building (the process of constructing a basement or lowering the existing floor level beneath an existing building) this movement is exaggerated because our contact with that building is now direct.
Movement monitoring reports provide clients and contractors with evidence of the extent of movement in their building at the designated monitoring points, before, during, and after the construction and/or demolition work.
“Early warning systems” like these are designed to notify interested parties as and when a buildings’ movement is starting to approach the given trigger levels and in exactly which parts of the building this heightened risk is occurring. All in order to avoid what could be a catastrophic disaster.
It is never too late to act…
Damage Monitoring Surveys
Even in the event where damage is already evident, it is often wise to call an engineering surveyor to monitor existing cracks, either using reflectorless monitoring points (in hard-to-reach places) or tell-tale gauges. What you really want to be sure of is that your structural movement is not continuing significantly over time. A damage monitoring survey proposal is often best reviewed by your structural engineer before deciding the extent and location of the required building movement monitoring system.
As a form of measured survey and very much part of the site engineering process, the cost of structural movement monitoring reports varies. It often depends on how large a monitoring survey you require, your project location, and how frequently movement monitoring visits are required. To get an idea of monitoring survey costs for your project click HERE to use our FREE Movement Monitoring Quote App.
This article is a brief overview of movement monitoring. If you have any questions or require any further information please don’t hesitate to contact us. Alternatively, you can find more about our structure monitoring services on our movement monitoring service page.
Here at SESE Ltd we have a wealth of experience and knowledge in providing both construction and demolition monitoring solutions across London and the Southeast.
To find out if your structure requires movement monitoring or for a structural monitoring survey quote please call our office on 02072780778 or book online HERE 24 hours a day 7 days a week.