Public buildings such as national or civic treasures, historic buildings like churches, halls and castles, and buildings of value to the community such as museums, libraries and art galleries can often suffer from foundation ground settlement or instability. This is commonly due to age, and as a result of the building’s original foundations being insufficient. If subsidence occurs to public buildings, preservation, rather than rebuilding is a priority, and it is extremely important that the remedial work is done with minimal intrusion.
Mainmark has built a strong reputation in the remediation works necessary to help ensure the stability of foundations for generations to come. Our non-invasive, cost effective and time efficient re-levelling methods can raise and re-support public buildings and historic houses of any size. As no excavations are required, in many cases, the building can continue to be used by the public during remediation.
What is subsidence and the causes?
Subsidence is the gradual downward movement of a building or structure due to changes in the soil conditions. If a public building like a museum or art gallery has been built on compressible clay soil, it is much more likely to suffer from subsidence compared to those built on other types of soil. Some of the most common causes of public building subsidence are:
The ground beneath the building or structure shrinks or swells – during wet weather the soil expands due to the moisture content and then contracts during dry months
Soil has not been correctly compacted during the construction of the building
Passing traffic or nearby excavations cause the ground to vibrate
The building has incomplete or old, inadequate foundations
Leaking drains cause sever water damage that weaken the soil and its foundations
Trees have been planted too close to the building, resulting in roots growing underneath it – Elm and Willow trees are those most likely to cause subsidence.
Signs of subsidence
Common signs of subsidence include cracks in the walls, uneven floors and other unexpected structural damage. If you do notice cracks in the wall, you will be able to identify whether or not it is subsidence by the nature of the cracks. They will usually be diagonal, wider at the top than the bottom and thicker than a 10p piece. Cracks can appear both inside the building in the plasterwork or outside the building in the brickwork.
Other common signs of subsidence include:
- Sinking concrete floors and gaps appearing near the skirting
- The structural movement of the building causes gaps to emerge between the doors and window frames, affecting how easily they open and close
- The public building begins to significantly lean in one direction
- Water damage appears as a result of structural movement
- Drain systems work inadequately or not at all
- Water in the sink flows in the opposite direction
If you identify any of these subsidence warning signs, it’s important you act quickly so the remediation process can begin. For more than 20 years, Mainmark has been providing cost-effective and efficient subsidence solutions for building’s around the world. To contact our experienced team, click here.
How does subsidence affect the operation of the building?
Public and historical buildings such as castles and palaces can date back centuries, meaning in many cases, the original building foundations have not been correctly executed. Because of this, subsidence can occur and if present and left untreated, will make the building unsuitable for public use. In extreme circumstances, this can lead to the complete closure of the building, meaning its valuable heritage is no longer accessible by the community.
How Mainmark can help
Mainmark has built a reputation, second to none, in the successful remediation works necessary to help ensure the stable foundations of public buildings for generations to come. These works can be particularly delicate and complex and so we have developed innovative and cost-effective solutions using a key-hole surgery approach that provides quick, non-invasive results.
Mainmark’s advanced technologies stabilise and support the ground beneath the structure, giving the heritage building a new lease of life.
For large or complex buildings, our integrated computer grouting technique enables a precisely controlled, gradual level correction process, minimising damage to often fragile masonry, glass and complex steel or concrete structures. Lifts of greater than 500mm are achievable with Mainmark’s unique solutions.
In many cases, the building can continue to be enjoyed by the public during remediation. Our experienced team can repair cracks in the walls, lift and re-level sinking floors and re-support structures, focusing on one area of the building at a time.
Our innovative key-hole methods are used. Small diameter holes are drilled through the ground slabs and foundations of the building which then allow grout injectors to be inserted. Flexible pipework connects these to computer controlled valves and hence to the grout pumps, and multiple survey points are installed and located across the building. These are continuously monitored by robotic survey instruments or laser levels to control the grout pumping and the gradual levelling of the structure.
Mainmark’s engineered resin injection is also another fantastic solution for many public buildings such as churches and libraries suffering from natural ground subsidence. This unique technology uses an insertion delivery method to raise, re-level, and re-support buildings and is a fast, non-invasive and overall cleaner alternative to traditional underpinning.
Benefits of Mainmark’s methods
Mainmark provide time-efficient solutions, completing large scale projects quickly and proficiently
Non-invasive, key-hole surgery methods are used and no excavation is required
There is little disruption to the building and no mess to clean up
Weak ground is stabilised and the public building becomes re-level and crack free
The historic building endures no further damage, instead it is raised and restored, allowing the structure to stand strong into the future