Anchors into the upper floor slabs

Cintec Anchors into Upper Floor Slabs

Two LPS Blocks, Bow London (Pre-Ronan Point) – AWT remedial panel ties and anchors into the floor beams to the upper floors.

Long Lasting Structural Repairs

AWT completed structural repairs to these two LPS blocks in East London. The work that involved the installation of a remedial panel tie system to the external large sandwich panels and anchors into the floor slab to the upper floors.

The photos above show the buildings 12 years later. The structural repair techniques used by AWT are designed to last.

Some structural repair contractors may offer cheaper quotes because they fail to follow the guidelines provided by the British Standards Institution and the Building Research Establishment Specification Digest. This can seriously impact the structural integrity of a building, especially mid and high rise blocks. Local councils, housing associations and landlords can rely on AWT to provide safe structural repair solutions.

AWT’s team of skilled structural repair specialists are available across London and the South East of England. Action Wall Ties (AWT) are specialists in masonry reinforcement and repair, providing professional solutions to a wide variety of structural problems. Contact us on 01227 721 255, or email us.

Remedial Panel Ties

Remedial Panel Ties for LPS Tower Blocks

Two LPS blocks, Thamesmead (Post-Ronan Point) – AWT remedial panel ties.

case 30 a - Remedial Panel Ties
In 2006 Action Wall Ties completed works to these two blocks, installing a remedial panel tie system to the external large sandwich panels.

case study 56e19bb6e04847.21142020 - Remedial Panel Ties

Not all structural repair contractors work to the same standards. AWT carefully follow the guidelines provided by the British Standards Institution and the Building Research Establishment Specification Digest. Adhering to these guidelines is vital to ensure the structural integrity of a building, especially mid and high rise blocks.

Companies and departments that award contracts for remedial building works recognise their legal and moral responsibility to ensure contracts are awarded based on safety considerations not just price. Local councils, housing associations and landlords can trust AWT to always provide cost effective, safe structural repair solutions.

AWT work along with architects, project managers and local authorities to restore LPS blocks to full structural integrity. AWT are available for large and small projects in London, Kent, Essex, Surrey and Sussex.

Action Wall Ties (AWT) are specialists in masonry reinforcement and repair, including panel ties to external sandwich panels and providing professional solutions to a wide variety of structural problems. Contact us on 01227 721 255, or email us.

AWT remedial panel tie

AWT remedial panel tie

Three LPS Blocks, Islington London (Post-Ronan Point) – AWT remedial panel tie

case study 56e19bcbb5c492.10986650 - AWT remedial panel tie

AWT completed the design and installation of a remedial panel tie system to the large sandwich panels and Internal threaded socket fixings to the concrete window mullions.

Action Wall Ties (AWT) are specialists in masonry reinforcement and repair, providing professional solutions to a wide variety of structural problems. Contact us on 01227 721 255, or email us.

Cavity Wall Construction History

Cavity Wall Construction History

This overview of the history of cavity walls looks at how the use of cavity walls started. It also looks at some of the problems that property owners need to be aware of and how AWT can help to solve these issues. Read on to find out about:

  1. Development of Cavity Wall Construction
  2. Wall Tie Corrosion
  3. Wall Tie Life Expectancy
  4. Wall Tie Damage by Corrosion
  5. Modern Wall Ties
simple horizontal - Cavity Wall Construction History
case 54 d - Cavity Wall Construction History
case 54 c - Cavity Wall Construction History
Masonry Damage from Corroded Wall Ties
Cracked Bricks from Failing Wall Ties
 
simple horizontal - Cavity Wall Construction History

Development of Cavity Wall Construction

Cavity wall construction has almost entirely replaced solid wall construction in the United Kingdom. It evolved in the latter years of the nineteenth century and became common in dwellings in northern and western Britain in the early 1900s.

Its widespread adoption as virtually standard in the construction industry happened throughout the building booms of the 1920s, ‘30s and ‘40s.

The gallery above shows the typical outer leaf (the external brickwork) of a cavity wall and the type of damage often associated with failing cavity wall ties.

When identifying whether a wall is of solid or cavity construction, something to be aware of is that the presence of headers in the brickwork (bricks laid with the smallest side facing out) is not always indicative of solid brickwork.

From the mid-1940s to the mid-1950s, “snapped headers” were often used in cavity wall construction to emulate the English bond brickwork pattern that was common in solid brickwork.

Action Wall Ties can help identify whether your property has cavity walls or solid brickwork and diagnose the underlying cause of structural defects.

In the early years, the skins of these cavity walls were held together by metal ties made from cast or wrought iron, mild steel or copper.

Wall Tie Corrosion

The corrosion of wall ties was first officially recognised in the 1960s in South Wales. At first, it was thought to be due to a combination of poor tie protection and exposure to the elements. Time has shown that many of the early ties and mortars were just more susceptible to corrosion.

Mild steel ties initially were either left unprotected or given a bitumen coating, but in the early 1930s zinc coatings or galvanising became accepted.

old corroded wall ties - Cavity Wall Construction History

The most common type of mild steel ties (under BS 1234) are strip ties (commonly known as vertical twist or fishtail) and wire ties (commonly known as butterfly or double triangle). The photo shows a range of traditional wall ties, all of which are prone to corrode and fail over time. In contrast, modern wall ties are carefully designed for strength and durability.

Wall Tie Life Expectancy

It is very difficult to predict the life expectancy of ties used in the construction of houses before 1945.

However, it can be fairly accurately predicted for those built between 1945 and 1964 :

  • Strip ties will probably last somewhere between 31 and 61 years
  • Wire ties will probably last somewhere between 15 and 31 years.

The expected life of ties used in construction between 1964 and 1981 is estimated at:

  • 23 to 46 years for strip ties
  • 13 to 26 years for wire ties.

ALL mild steel wall ties will eventually corrode – the only question is when!

As shown in the photo, Action Wall Ties can survey cavity wall ties by drilling small inspection holes and using an endoscopic camera to assess the wall ties. Contact us to arrange a wall tie survey.

case 54 a e1642420655249 - Cavity Wall Construction History

Wall Tie Damage by Corrosion

The key here is catching the problem as early as possible. If the symptoms are recognised before deterioration has progressed too far, the walls may be re-stabilised rather than needing to be re-built.

Old ties must be located using an electronic detector and replaced with a suitable corrosion-resistant remedial fixing.

Finally, existing ties will need to be isolated to prevent further damage to the outer leaf of brickwork. Corrosion of a tie within the inner leaf of a cavity wall is unlikely to become significant as they are embedded in a dry environment.

AWT’s specialist equipment allows them to isolate failing wall ties and install remedial wall ties with minimal disruption by working from the outside of the building.

Ferrous oxide (rust) will result when embedded mild steel wall ties corrode. This will expand to several times the thickness of the metal it has resulted from, often breaking through the outer leaf of the brickwork (sometimes splitting the bed joints) and causing either lifting or bowing of the walls and damage to internal finishes.

simple horizontal - Cavity Wall Construction History
rusty wall tie repairs kent - Cavity Wall Construction History
wall tie 1 - Cavity Wall Construction History
wall tie 2 - Cavity Wall Construction History
wall tie - Cavity Wall Construction History
rusted wall tie - Cavity Wall Construction History
rusted wall tie1 - Cavity Wall Construction History
Rust Damaged Wall Tie
Rusty Wall Ties
Failed Wall Tie
Crumbling Wall Ties
Rusted Wall Tie
Corroded Wall Ties
 
simple horizontal - Cavity Wall Construction History

From a structural perspective, this leaves the wall vulnerable to vertical and wind loads, especially in the case of large gable and unreturned walls. The instability of the wall will eventually result in the ties corroding away completely, necessitating the rebuilding of the wall. The gallery shows how corrosion causes the cavity wall ties to lose strength and eventually crumble away.

Modern Wall Ties

As shown below, Action Wall Ties uses a range of modern cavity wall ties that are far superior to traditional wall ties. Using their many years of experience, AWT selects the most appropriate remedial wall tie style for each project.

remedial stainless steel wall ties - Cavity Wall Construction History

There are 3 main types of replacement wall ties:

  1. Mechanical
  2. Helical
  3. Resin or grout bonded

All AWT’s replacement wall ties are made from high-grade stainless steel. They are designed to restore structural integrity and provide a long lasting solution to cavity wall tie issues.

Equipment designed by AWT can also realign brickwork that is bulging and bowing due to failing wall ties before installing new wall ties and lateral restraints.

Kent based Action Wall Ties (AWT) are specialists in wall tie surveys and replacement, providing professional solutions to a wide variety of cavity wall problems. We serve domestic and commercial customers, local authorities, housing associations and insurance companies across London, Kent, Essex, Sussex and Surrey.

Contact us to discuss your requirements or book a survey on 01227 721 255, or email us.

 

Large Panel System Remedial Works

Large Panel System Remedial Works

Action Wall Ties has a long history of working with many Large Panel System high rise blocks (LPS blocks). Working closely with structural engineers, AWT can install differing options of upper floor reinforcing / tying together as well as tying of the sandwich panels with AWT designed incline pins and mullions fixings for LPS panels.

case study 5b62ed5e948159.52637073 - Large Panel System Remedial Works

LPS Structural Problem

Brodick House is a 22 floor large panel system high rise block in Tower Hamlets, East London. As with many tower blocks built using the large panel system, the structure required remedial work to ensure its structural integrity.

LPS Remedial Work

Remedial works included:

  • Cintec Cementitious Sock Anchors
  • Remedial Corridor Reinforcing Angles
  • Remedial Spandrel Panel Tie Back Fixing

Action Wall Ties have extensive experience in defects commonly associated with LPS buildings. Working closely with main contractors and structural engineers, repair strategies have been developed that include strengthening ties, internal steel work and fixings, external stainless steel plates, brackets, and panel ties.

Brodick guauge - Large Panel System Remedial Works

We have also developed tying methods for the sandwich panels. This work is always undertaken with care and attention to detail by highly skilled operatives using specially designed equipment.

Action Wall Ties used purpose manufactured dollies to transport and position the corridor reinforcing steel angles. AWT designed lifting cradles were used to lift the angles and fixed them in place.

Two coats of water based intumescent paint were also applied to provide one hour fire protection.

Long Lasting Structural Repairs

The remedial work was designed to be cost effective and long lasting. The photos below show the block 15 years after completion of the works. This illustrates the quality and permanence of AWT’s structural repair techniques.

Councils and housing associations can rely on AWT to provide efficient, cost effective, high quality structural repairs. AWT ensure all repairs are carried out following the guidelines provided by the British Standards Institution and the Building Research Establishment Specification Digest.

Greater London, Essex, Sussex and Kent are all covered by the professional services of Action Wall Ties.

Action Wall Ties (AWT) are specialists in LPS remediation, reinforcement and repair of tower blocks. We provide professional solutions to a wide variety of structural problems encountered with high rise buildings. Contact us on 01227 721 255, or email us.

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