When AWT surveyed this 1970s cavity wall bungalow in Canterbury it was obviously in a perilous condition. The gable walls at either end of the property were leaning far beyond the tipping point. Urgent action was required to prevent collapse.
AWT provided a permanent and cost-effective structural repair without rebuilding work on the walls or removal of the roof.
Distorted Roof & Leaning Gable Walls
The Structural Problem
The roof structure including the roof trusses and both brickwork gable walls were leaning precariously to the left. The walls were some 250mm/9.8 inches from vertical. This is far beyond the tipping point and makes structural collapse inevitable.
Leaning Gable WallSevere Lean in Gable WallsLeaning Gable Brickwork
Inspection of the roof revealed no braces had been installed on the roof trusses. The roof tiles, fascia boards and soffits had warped with the structural movement but remained intact. The property also lacked effective wall ties.
These deficiencies in the original construction left the gable walls unrestrained. Over time, the weight of the roof structure and the heavy roof tiles caused the gable walls to lean significantly.
During Wall RealignmentDuring Brickwork RealignmentDuring Gable Straightening
AWT designed and installed temporary steel anchors on the right side of the building and attached steel frames to both gable walls. The structure was realigned using AWT’s specialist hydraulic and screw-powered jacks. This shifted the gable brickwork, roof, fascias and soffits back to the vertical position.
To ensure a permanent repair, AWT installed roof truss braces and wall ties. The brickwork gable walls were reinforced and restrained to prevent leaning.
Disturbed areas of mortar and damaged bricks were repaired with carefully matched replacements. The result is a nearly invisible repair with no visible fixings, no rebuilding work and minimal disruption for the residents.
After Gable Wall RealignmentAfter Structural Repairs to Gable
AWT provides cost-effective structural repairs for a wide range of structural issues. Our specialist tools and techniques allow rapid and permanent structural repairs without the high price and disruption of rebuilding work.
We work with structural engineers, architects and project managers to find economical and effective solutions. We operate not only in Kent, but across London and the whole South East of England.
To book a time for one of our surveyors to visit your property or to discuss your requirements, call us today on 01227 721255, email us at enquiries@actionwallties.co.uk or use our contact form to get in touch.
Remedial Wall Ties & Boot Lintel Repairs for 60s/70s House in Thanet
This detached house in Broadstairs, Kent, has a typical 1960s/1970s design and construction. Many similar properties are now developing the same structural problems.
A structural survey of the property indicated issues with the concrete boot lintels and the wall ties. The new owners called in AWT to stabilise the superstructure and protect their investment. Prompt structural repairs prevented the structural defects from causing further damage and avoided more extensive repairs.
Failing 60s/70s Boot Lintels
How to Identify Boot Lintels
Failing Wall Ties
The door and window openings were constructed using concrete boot lintels; easily identifiable by the distinctive concrete beams above doors/windows that do not extend beyond the width of the opening. Concrete boot lintels are prone to rotate. This had caused cracking in the internal plaster and cracked, open mortar joints in the external brickwork. The original cavity wall ties were also failing, leaving the outer brick skin unrestrained, and vulnerable to bulging/failure.
The Structural Problem
The property was suffering from 2 main defects that are very common in 1960s/1970s properties; rotating concrete boot lintels and failing wall ties.
Rotation of Boot Lintels:
A fundamental flaw in the installation of concrete boot lintels in 60s/70s properties means that the weight of the heavier brick outer skin is too great for the softer inner blocks to support. The boot lintel rotates, causing gaps to open up, compressing the blocks of the inner wall and allowing the outer brickwork to sag.
The early symptoms of boot lintel problems, as seen below, are cracks in the internal plaster above or radiating from the top corners of doors and windows. It also caused cracking and distortion of the supported brickwork above the doors and windows.
Failing Boot Lintels
Cracks Above Doors/Windows
Cracks Above Window
Cracks in Window Plaster
Common symptoms of concrete boot lintel problems:
Cracks in the internal walls and ceilings above windows/doors
Warped window/door frames – difficult to open and close
Cracks in the visible part of the concrete lintel
Stepped cracks in the brickwork above windows/doors
Dropping of the brickwork above windows/doors
Bulging or bowing brickwork above windows/doors
Traditional building repairs – making good the cracks and open joints – treat the symptoms, not the cause. If the rotation continues, serious damage caused by the rotation may result in the necessity to replace the lintels. To avoid further damage to the brickwork, the boot lintels require specialist structural repairs.
Rotating Boot Lintel Causing Gaps & Cracks
Stepped Cracks Due To Failing Boot Lintel
Gaps Above Concrete Boot Lintel
Boot Lintel Defect Causing Compression Cracks
Failing Wall Ties & Inadequate Restraint:
Investigation of the wall ties revealed the existing Wire Butterfly Ties were in varying stages of corrosion and were beyond their useful life. The building had suffered some movement for a prolonged period and was progressive due to a combination of ageing, ineffective and/or inadequate wall tying and restraining plus the effect of rotating fenestration boot lintels all contributing to a lack of structural stiffness.
The progressive corrosion of the existing wall ties left the property vulnerable to vertical and wind loads, especially to large gable and unreturned walls. Instability of the wall will result if the ties corrode away completely, resulting in a need to rebuild the wall. Prompt action to install remedial wall ties will avoid more costly and disruptive repairs in the future.
Plaster Cracks in Corners
Vertical Plaster Cracks
The Structural Repair Solution
The structural repairs by AWT tackle the root cause of the masonry defects and add tensile strength thus reinstating the brickwork’s integrity.
Structural repairs included:
Bed Joint Reinforcement Beaming
Fenestration Boot Lintel Treatment
Grout Tie Injection
Remedial Wall Ties
The AWT team installed specially developed prop supports to anti-rotate the boot lintel back into place. Specialist diamond drilling techniques were used to drill through the brickwork into the boot lintel and install resin-bonded stainless steel sheer pins.
Concrete Boot Lintel Repairs
Repaired Boot Lintel
New pad-stones were installed by providing temporary support to the underside of the lintels, carefully removing sufficient plaster to expose the lintel, cutting out the internal skin and forming a pad-stone to spread the load onto the internal skin. The area was left ready for plastering.
The new wall ties, bed joint reinforcement beaming and grouted ties stabilised the superstructure, reconnecting the inner and outer walls and strengthening the overall structure.
AWT provide cost-effective structural repairs for a wide range of structural problems including failing wall ties and concrete boot lintel problems. We operate not only in Kent but across the whole of London and the South East of England.
To book a time for one of our surveyors to visit your property or to discuss your requirements, call us today on 01227 721255, email us at enquiries@actionwallties.co.uk or use our contact form to get in touch.
This semi-detached home near Maidstone in Kent was built in the 1960s or 1970s. The property is a cavity wall construction with no visible external lintels above the doors or windows.
In common with many properties built in the 60s and 70s, it suffered from brickwork issues above the doors and windows. It showed signs of previous, unsuccessful attempts to repair the brickwork by traditional building methods. Structural repairs were required to avoid the failure of the lintels and the collapse of the unsupported brickwork above the lintels.
There are many housing estates across the South East, including many former council house estates, that are built in the same way. AWT has helped homeowners and housing associations find a cost-effective solution to brick-lintel defects.
Common symptoms of brick lintel issues include:
Gaps opening up in brickwork
Cracks in brickwork, especially diagonal, stepped cracks
Cracks in plaster around doors and windows
Sagging and dropping brickwork above doors or windows
Difficulty opening or closing doors and windows
The Structural Problem
The AWT survey found dropping and cracking to the external brickwork that forms the supporting lintel above the window openings and supported brickwork above, which if not treated would result in their failure.
As can be seen in the photos below, previous attempts had been made to repair the cracks. Traditional building methods had only provided a temporary, cosmetic repair. Cracks could be clearly seen running through the areas that had been repointed.
Inside the property, cracks had opened up in the plaster around the windows.
Cracking/Dropping Brickwork
Plaster Cracks Near Windows
Previous Attempted Repairs
Failing 60s/70s Brick lintels
The brick lintels had been deteriorating over a long period. The failure of the existing window and door lintels was causing the brickwork above the lintels to drop and crack due to a lack of support.
As well as causing cracks and gaps in the brickwork, the pressure of the unsupported masonry will warp doors and windows making them difficult to open and close. Without appropriate structural repairs, the outer skin of the brickwork would collapse.
Gaps in Brickwork
Cracks Above Windows
Dropping Brick Lintel
Cracking & Dropping
The Structural Solution
The remedial works were designed to restore the masonry to the correct alignment and add tensile strength by installing state-of-the-art fixings within the brickwork. The formation of continuous beams within the existing masonry redistributes the upper-storey loads and restrains diagonal cracking and bulging tendencies.
AWT’s specialist precision drilling equipment allowed the fixings to be installed from the exterior of the property with minimal disturbance to the residents.
AWT’s specialist structural repair techniques provided a long-term repair without visible fixings or rebuilding work.
Repairing 60s/70s Lintels
60s/70s Lintel Repairs
Realign & Reinforce
Instal temporary supports to the underside of door & window openings
Removal of debris from brickwork cracks
Realign lintels using hydraulic equipment
Instal stainless steel corded joint reinforcement within the brickwork to form a load-bearing beam within the masonry
Instal helical stainless steel pins to secure the brick lintels
Instal resin bond stainless steel ties forming truss ties
Reconnect masonry using grouted 8mm helical bar
Instal remedial wall ties to debonded cavity brickwork
Re-point disturbed areas of mortar with colour-matched mortar
Action Wall Ties are specialist structural repair contractors with the skills and experience required to repair properties of all ages. AWT works on domestic and commercial projects for homeowners, housing associations, structural engineers, architects, project managers and local authorities.
AWT are available in Kent, London, Essex, Surrey and Sussex. To arrange a survey or to discuss project details, please use our contact form, email us or call us on 01227 721 255.
This 1950s / 1960s home in Erith, Kent has brick support lintels above the doors and windows made up of upright bricks known as soldier brickwork courses. The soldier brick lintels, also known as straight arches, were dropping and cracking. Without suitable structural repairs the lintels and the brickwork above would fail. This would damage the UPVC windows and doors and eventually lead to the collapse of the brickwork. This problem often occurs after new windows and doors have been fitted to properties of this era.
The Structural Problem
The brickwork above the doors and windows of this semi detached home near Dartford, Kent was supported by lintels comprised of upright, soldier bricks. Deep cracks had formed around the soldier brick lintels, the soldier bricks were also dropping. This was leaving the brickwork above unsupported, putting pressure on the UPVC windows and doors.
Failing soldier brick lintels can lead to warping of the double glazed UPVC replacement windows and difficulties opening doors and windows. The masonry above the lintels will begin to drop and sag. Eventually, the lintels would fail, causing the brickwork above to collapse.
Common Symptoms of Soldier Brick Lintel Failure:
Cracks around lintels above windows & doors
Difficulties opening & closing windows & doors
Sagging brickwork above windows & doors
Symptoms often become more noticeable after fitting replacement windows & doors
The Structural Repair Solution
The structural inadequacy of the straight arch lintels was repaired by reinforcing the masonry above and forming a composite beam within the external brickwork. The formation of deep masonry beams within the existing masonry supports the masonry and maintains the integrity to the brickwork.
The 3 techniques used by AWT were:
Bed Joint Reinforcement Beaming
Fenestration Lintel Repair
Resin Bonded Ties.
This reinstated the uniformity of the brickwork while at the same time providing restraint, preventing the brickwork from dropping and cracking.
The AWT team put temporary supports in place before using their specialist realignment equipment to move the dropping lintel back into line with the adjacent brickwork. Then rows of twin 8mm stainless steel corded joint reinforcement fixings were installed within the masonry forming a deep masonry beam. Grouted helical stainless steel pins were also installed to reattach the soldier course forming the lintel to the brickwork above and resin ties fixed to the inner skin within the beam area.
Cracked or disturbed areas of pointing were made good with colour matched mortar. The precision drilling techniques used by AWT results in the minimal disturbance of the mortar in the brickwork.
Completed Soldier Brick Lintel Repairs
Why Choose AWT for Structural Repairs?
Unlike traditional builders, AWT can
treat the root cause of the structural defect
repair structural issues without partial demolition and rebuilding work
make structural repairs without visible fixings
provide a long-term solution to structural failings
make repairs with minimal disruption for residents
AWT provide cost-effective structural repairs for a wide range of structural faults including dropping soldier brick lintels and cracked brickwork. We operate not only in Kent but across the whole of London and the South East of England.
To book a time for one of our surveyors to visit your property or to discuss your requirements, call us today on 01227 721255, email us at enquiries@actionwallties.co.uk or use our contact form to get in touch.
Bulging & Cracking Brickwork Across Front of Victorian Semi Detached Houses
These 2 Victorian semi detached houses in Egham, Surrey had a significant bulge in the brickwork above the first floor windows. There was also a failing brick arch lintel and cracking to the brickwork. Without swift action the masonry would collapse.
AWT were called in to repair the defects and allow the homeowners to avoid slow, expensive and disruptive rebuilding work. Equipment designed by AWT was used to realign the brickwork, stabilise and reinforce the masonry and then install new wall ties and lateral restraints.
The Structural Problem
The AWT survey team visited the property in Surrey, TW20 to identify the root cause of the visible bulging of the masonry at the front of the property. The AWT survey team quickly identified that this Victorian semi was built using cavity wall construction and that failing cavity wall ties were likely a root cause of the problem.
A limited inspection of the wall ties was undertaken by drilling 12mm holes in the outer leaf of brickwork to view within the cavity via an endoscope. This confirmed the diagnosis of failing wall ties, as can be seen from the photos taken with the endoscope, as the corrosion of the metal was clearly visible. The mild steel ties were all in a similarly heavily corroded condition and showing signs of de-laminating.
Horizontal cracking, lifting and opening up of joints was noted at irregular intervals on the front elevation. Metal ties were located behind the cracks, with an electronic wall tie locator.
Corrosion of the embedded mild steel wall ties was causing them to expand to many times their original size. This was damaging the outer leaf of brickwork, splitting the bed joints and causing either lifting or bowing of the walls and damage to internal finishes. This left the wall vulnerable to vertical and wind loads, especially such a large gable wall.
Without structural repairs the wall would continue to bow further and eventually collapse. Traditional building methods would have required the partial deconstruction and rebuilding of the front of the properties.
The Structural Repair Solution
Unlike some cavity wall tie repair contractors, AWT always works to the standards laid out in the Building Research Establishment Specification Digest. This means that the separation between new wall ties, the layout pattern of the new wall ties and the material used to manufacture the new wall ties all meet the highest standards to ensure a safe, long term structural repair.
To avoid failure of the brickwork and brickwork arch AWT realigned the bulged brickwork, installed new stainless steel wall ties, isolated the old ties to prevent them causing further damage and formed a composite beam within the external brickwork. The formation of deep masonry beams within the existing masonry supports the masonry and maintains the integrity of the brickwork.
AWT use their own custom designed hydraulic realignment equipment and diamond bladed precision drilling rigs. This allows the new fixings to be installed with minimal disturbance to the masonry. A variety of specialist fixings were introduced into the brickwork to restore the strength and stability of the wall.
As can be seen in the photo above, when the work is complete there are no visible fixing either inside or outside the property. The AWT team also take the time to colour match any replacement bricks as well as matching the colour, texture and pointing style of the mortar where work has taken place.
AWT provide cost effective structural repairs for a wide range of structural faults including failing cavity wall ties and bulging brickwork. We operate not only in Surrey but across the whole of London and the South East of England.
To book a time for one of our surveyors to visit your property or to discuss your requirements, call us today on 01227 721255, email us at enquiries@actionwallties.co.uk or use our contact form to get in touch.
Wall tie treatment and weather struck re-pointing to 1950s style two-storey semi-detached house of the type typical of Kent and London.
The subject property comprised a 1950s style two-storey semi-detached house of cavity wall brick construction.
Structural Problems with these wall ties
The existing wall ties viewed were found to be mild steel vertical twist ties, commonly known as fishtail ties. The wall ties were found to be heavily corroded, fractured and delaminated.
The corrosion of the embedded mild steel wall ties had resulted in the forming of ferrous oxide, which had expanded to many times its original thickness, lifting and cracking the brickwork.
Solution for a wall tie repair and replacement
AWT completed a remedial programme providing a viable repair through the introduction of a pattern of remedial wall ties and isolating the existing ties, together with general brickwork repairs and weather struck re-pointing.
Action Wall Ties (AWT) are specialists in masonry reinforcement and repair, providing professional solutions to a wide variety of structural problems in Kent and London. Contact us on 01227 721 255, or email us.
Wall tie treatment and cavity cleaning to 1950s semi-detached house to provide a structural repair for rusting wall ties and DPC issues.
The subject building was a conventional 1950s cavity-built semi-detached house.
Problem – corroded de-laminated wall ties
An AWT investigation with a metal detector and an endoscope revealed that the wall ties to the front, right side and rear elevations were galvanised mild steel vertical twist ties, all in a similar heavily corroded condition, showing signs of de-laminating.
Side gable wall:
This had a significant bulge at first floor level from the front to the window. This area required the external skin to be carefully dismantled and rebuilt.
Corroding wall ties were clearly visible. The internal walls at ground floor level were also found to be damp.
Corrosion of the embedded mild steel wall ties had resulted in the forming of ferrous oxide, which had expanded the metal to many times its original thickness, lifting and cracking the brickwork. It was considered likely that the lateral movement noted was due to the absence of effective wall ties.
Bridging of cavities at DPC:
Our investigation revealed that the building had areas within the cavity that were blocked with decayed mortar that bridged the DPC.
Discussion
Wall ties:
AWT’s opinion, based on the Building Research Establishment (BRE)’s recommendations, was that the symptoms/defects noted were consistent on all elevations requiring remedial work. It was considered that the building would benefit from remedial wall tie replacement and the isolation of the existing ties.
Bridging of cavities at DPC:
The bridging of the DPC had rendered it ineffective and could result in rising damp.
Solution – remedial wall tie replacement
AWT completed a remedial scheme providing a viable repair by introducing remedial wall ties, isolating the existing ties and cavity cleaning.
Wall tie treatment:
AWT operatives completed remedial wall tie treatments to the front, right side and rear elevations in accordance with AWT’s Wall Tie Treatment – Generic Repair.
Cavity cleaning:
We cleaned the cavities to the ground floor DPC at the front, right side and rear elevations in accordance with our specifications and AWT’s methods. This meant the removal of sufficient external brickwork to enable the removal of discarded mortar debris, leaving the cavity clear to below the DPC while at all times maintaining the integrity of the wall.
Action Wall Ties (AWT) are the South East specialists in wall tie replacement, masonry reinforcement and repair, providing professional solutions to a wide variety of structural problems. Contact us on 01227 721 255, or email us.
Bowing gable wall to a 1950s style semi-detached house in Sittingbourne, Kent. Remedial wall ties, isolating the existing ties, bed joint reinforcement beaming, crack stitching and lateral restraints.
The subject property in Swale, Kent, comprised a 1950s style two-storey semi-detached house of cavity brickwork construction.
Problem – Gable wall bowing & cracking
The gable wall: The right side gable wall had a visible outward bulge at the centre of the wall at first floor level and significant cracking was noted (no corresponding internal cracking was present). The front elevation external skin was rebuilt after suffering damage in a hurricane. No downward movement at DPC level was noted.
An AWT investigation with a metal detector and an endoscope revealed that the wall ties viewed to the right side gable wall and rear elevations were mild steel vertical twist ties, all in a similar heavily corroded condition and showing signs of de-laminating.
Horizontal cracking, lifting and opening up of joints were noted at irregular intervals on the right side and rear elevations, with corroding ties clearly visible.
Discussion
Right side elevations: We believed that the movement was progressive, due to ineffective and/or inadequate restraining, and not attributable to significant subsidence.
Wall ties: Our opinion, in accordance with the Building Research Establishment’s recommendations, was that the symptoms noted above were likely to be representative of the majority of the cavity wall ties to the right side, and the main rear elevation suffering from corrosion.
It was believed that the building’s right side and main rear elevation would benefit from remedial wall ties and the isolation of the existing ties.
Structural Repair Solution
AWT completed a remedial scheme providing a viable repair by introducing remedial wall ties, isolating the existing ties, then employing bed joint reinforcement beaming, crack stitching and lateral restraints.
Remedial wall ties and isolation of existing ties: Our operatives undertook remedial wall tie treatment to the right side and main rear elevations in accordance with AWT’s wall tie treatment – Generic Repair.
Bed joint reinforcement beaming: The introduction of two rows of twin 8mm stainless steel corded joint reinforcement forming a deep masonry beam – as indicated with red double dotted lines on our proposal plan.
Crack stitching: We stitched localised cracks with the introduction of single 8mm stainless steel corded joint reinforcement – as indicated by red single dotted lines on our proposal.
Lateral restraints: At approximately 900mm centres we drilled for, and screwed directly into alternate timber floor joist’s end grain or into the side grain, 8mm stainless steel lateral restraints into the timber floor and ceiling joists, all resin bonded to the masonry along with corresponding wall ties – as indicated with green stars on our proposal plan.
Make good the pointing: To the cracking schedule for reinforcement listed above, and to areas of weakness to pointing to the right side elevation, we raked out the existing cracked mortar and repaired with new coloured sand and cement mortar to approximately 20mm in depth. AWT operatives are highly skilled in traditional building methods and always attempt to match replacement bricks, pointing styles and mortar colour to be sympathetic with the existing building.
Homeowners, landlords, housing associations and councils across Kent, London, Surrey and Sussex can call on AWT’s experts to repair rusting wall ties and other structural problems. Action Wall Ties (AWT) are specialists in gable wall repairs, masonry reinforcement and repair. We provide professional solutions to a wide variety of structural problems. Contact us on 01227 721 255, or email us.
Kent Bungalows with failing lintels and localised subsidence
Bungalows with failing lintels and localised subsidence – bed joint reinforcement beaming, fenestration lintel repair and crack stitching
This small development comprised detached purpose-designed bungalows and maisonettes for the elderly. Each block was of a similar design, facing a common central garden. To the front elevation of each block there was a central gabled section accommodating a first floor with a single-storey wing on both sides.
Structural Problems
Signs of distortion and distress with cracked and dropped brick arches, both cracking to the brickwork to the ground and first floor windows and cracking to the brickwork below the ground floor windows were noted.
Discussion
We believed that the movement noted was progressive, due to inadequate lintels. The cracking noted below the ground floor window could be attributed to some localised subsidence. The buildings were to undergo a window replacement programme and it was requested that our proposal included the restraining of the single brick arch above each window.
Structural Repair Solution
AWT completed a remedial scheme providing a viable repair by introducing bed joint reinforcement beaming, fenestration lintel repair and crack stitching.
Bed joint reinforcement beaming: The introduction of two rows of twin 8mm stainless steel corded joint reinforcement, forming a deep masonry beam – as indicated with red double dotted lines on our proposal images.
Fenestration lintel repair: To the underside of the fenestration openings head we drilled for, and injected grouted, 8mm helical stainless steel pins through the brick arch, passing into the line of the deep masonry beam installed within the existing masonry – as indicated with green parallel lines on our proposal images.
Made good the pointing: To the cracking schedule for reinforcement, we raked out the existing cracked mortar and repaired with new coloured sand and cement mortar to approximately 20mm in depth. AWT operatives are highly skilled in traditional building methods and always attempt to match replacement bricks, pointing styles and mortar colour to be sympathetic with the existing building.
Action Wall Ties (AWT) are specialists in masonry reinforcement and repair, providing professional solutions to a wide variety of structural problems in and around the Canterbury Kent area. Contact us on 01227 721 255, or email us.
Large expanse of brickwork with extensive cracking
Contemporary terrace of houses with large expanse of brickwork with extensive cracking – introducing remedial movement joints and repair the cracking brickwork.
The subject buildings were a terrace of domestic residences of cavity construction, circa 1970s typical of London and Kent.
The Structural Problems
Our inspection revealed many significant cracks to and from windows and to the lower valley of the roofs, along with evidence of many previous repairs. No expansion joints were noted.
Discussion
The cracking noted was not attributable to significant subsidence but to seasonal moisture, thermal expansion and contraction (i.e. hygrothermal).
This considerable length of continuous brickwork had been constructed without the benefit of any expansion joints.
Structural Repair Solution
AWT completed a structural repair / remedial scheme that provided a viable repair by introducing expansion joints, bed joint reinforcement beaming and crack stitching.
With a hydraulic twin diamond bladed saw we cut a 10mm wide joint to the full depth of the external skin and thereafter formed a flexible joint, all in accordance with AWT’s methods.
Action Wall Ties (AWT) are specialists in masonry reinforcement and repair, providing professional solutions to a wide variety of structural problems in London and Kent. Contact us on 01227 721 255, or email us.
