Stabilisation of superstructure Archives - Page 2 of 2

Victorian Crack Stitching and Lintel Repair

Victorian Property: Crack Stitching & Lintel Repair

Extensive superstructure reconnection and reinforcement after underpinning for a Victorian house in North West London.

The subject building was a substantial Victorian traditionally built semi-detached domestic house in London, NW3.

The Structural Problem

Click on the gallery images below to see the full extent of the damage caused by the structural issues. Evidence of previous, unsuccessful attempts to fix the structural issues by traditional building techniques can also be seen.

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Signs of distortion and distress were noted, with localised cracked and dropped brick arches to the first and second floor levels of the square bay.

Significant cracking was noted to the external brickwork running from and to the ground, first and second floor window openings. The brick arch was missing from the first floor window and distortion, cracking and dropping were noted to the ground and second floor arches. The first and second floor window openings had temporary supports.

Causation

The movement noted was attributed to subsidence. Downward movement had allowed the brick arch to spread and drop and the brickwork to crack. The downward movement had been addressed by a recently completed underpinning scheme. Some de-bonding of the brickwork was also noted.

The Structural Repair Solution

1. Bed joint reinforcement:
We introduced two rows of twin cord reinforcement, forming a deep masonry beam – as indicated with red double dotted lines on our proposal images.

2. 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.

3. Bay window repair:
To form a beam and reconnect the bay window elevational brickwork, we diamond-drilled a 20mm hole through each elevation, chased into the main elevation and injected grouted 8mm helical bars – as indicated with green horizontal parallel lines on our proposal images.

4. Crack stitching:
To stitch localised cracks we introduced single 8mm stainless steel corded joint reinforcement – as indicated with red single dotted lines on our proposal images.

5. Wall ties to de-bonding brickwork:
To brickwork within the beamed area and arches, where brickwork was believed to be de-bonding, we drilled for and resin bonded 6mm stainless steel remedial ties and re-pointed disturbed areas with a sand and cement mixture.

Signs of distortion and distress, with localised cracking, were noted to the external brickwork to the front entrance archway bridge, along with cracked voussoirs and the dropping of the brick arch and outward movement.

6. Resin bonded ties:
To stabilise the brickwork archway bridge, we introduced truss ties. To form the truss we drilled a 14mm hole at 45 degrees to the required depth, opened the entrance hole to 18mm, resin bonded 10mm stainless steel threaded rods, drilled a horizontal 14mm hole to the required depth, inserted the 10mm stainless steel threaded rods, fixed nuts and washers, resin bonded to the inner wall, tightened nuts to both sides and resin bonded to the outer brickwork.

7. Making good and pointing:
We raked out the existing 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.

High Quality Structural Repairs

The photos below show the property 14 years after the work was completed. The high quality structural repairs carried out by AWT are designed to last. Unlike traditional building repairs, our techniques get to the root cause of structural defects.

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

Edwardian Stucco column remediation

London Edwardian Stucco column remediation

Edwardian portico structure with stucco columns cracking and failing – stabilising remediation works involved precision diamond drilling into the edge of the rounded columns directly into the centre of a half brick wall and the injection of grout

The subject building was a substantial, traditionally-built, elegant Edwardian Stucco finished domestic house in Central London.

This period property required work to remedy cracking and parting of the entrance porch structure without detracting from the look of the property.

Action Wall Ties have highly trained staff with a wealth of experience in dealing with period properties. AWT used their own design of diamond drilling equipment to drill for, and install, ties to strengthen the structure. The property was then made good using special mortars to match the existing finish.

Detailed Case Study

Defect

Cracking to the junctions of the front portico stucco columns with the main elevational walls was reported and noted.

Discussion

An underpinning scheme was completed, addressing the downward movement leaving the superstructure to be reconnected. Action Wall Ties’ remediation works were designed to assist in restraining the masonry to return the integrity to the structure.

Structural repair solution

The remediation works involved precision diamond drilling into the edge of the rounded columns, directly into the centre of a half brick wall by 1800mm each way to accommodate the injection of grouted ties, reconnecting the columns and walls (as indicated with green lines).

With the structure stabilised the cracked junctions of the columns with the main elevation were raked out cleaned and injected with cementitious grout, finished and made good with concrete repair mortar.

Action Wall Ties have, over many years, developed specialised equipment and methods to facilitate precision diamond drilling in almost any location, into almost any substrate, drilling 20mm diameter holes up to 3 meters long, through to 80mm diameter holes to almost any length, to accommodate the proposed remediation works (i.e. the removal of corroding steel and or installing many types of fixings).

Action Wall Ties have developed methods, and trained skilled experienced operatives, to strive to finish works to be sympathetic with the existing by attempting to match replacement bricks, pointing style and mortar mixture for texture and colour.

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

Stabilising stone and flint dormer window

Stabilizing stone and flint dormer window at King’s School, Canterbury – diamond drilling for, and installing, grouted ties

King’s School is possibly the oldest school in England, believed to have been established over 400 years ago. AWT were engaged to undertake remedial works to stabilise a stone and flint fronted gable dormer window of this substantial, historic school building. We used lateral restraints and grout ties to remedy the problem and offer an effective repair solution.

Problem – movement and rotation of gable masonry

• The dormer gable masonry was of stone window mullions and copping stones with a flint infill backed with brickwork.

• The dormer gable masonry had suffered from significant outward movement, leaving a gap between the flashings and the dormer roof.

• The masonry appeared to be rotating outwards on the joints to the stone window mullions.

• No fixings to the masonry and the roof structure were noted.

Discussion

From our findings it was apparent that the building had suffered from movement over a period of time. It was deemed that this movement was progressive, due to current ineffective and/or inadequate restraining.

The Repair Solution – Lateral Restraints

AWT completed a remedial scheme providing a viable repair, through the introduction of lateral restraints and grout ties to reconnect the substance of the wall and restrain the same.

• Grout ties: To connect the substance of the masonry stone and flint of the gable wall, AWT installed remedial grout ties by drilling for, and injecting, grouted 8mm helical bar – as indicated with green stars and parallel lines on our proposal plan images.

• Lateral restraints: In conjunction with the grout ties we installed stainless steel ties, screwed into the side grain of the timbers behind and resin bonded to the masonry – as indicated with yellow stars on our proposal plan images.

Action Wall Ties (AWT) are specialists in masonry reinforcement and repair including historic flint and stone walls, in Kent, Surrey, London and Sussex.

Our Lateral restraint solutions are permenant and effective, creating a better than new outcome.

We are successfully providing professional solutions to a wide variety of structural problems. Contact us on 01227 721 255, or email us.

Stabilising Victorian gable wall stone corbels

Stabilising Victorian gable wall stone corbels, pediment and copings – diamond drilling for, and installing, grouted and Cintec ties

The subject building is a substantial Victorian traditionally-built house featuring a gable embellished with substantial supporting stone corbels, coping stones and pediment in North London.

This property required work to remedy the rotation of the supporting stone corbels and dislodged copings without detracting from the look of the property.

Action Wall Ties have highly trained staff with a wealth of experience in dealing with period properties. We used our own design of diamond drilling equipment to drill for, and install, ties strengthening the structure.

Detailed Case Study

Problem: Stone Corbel Movement

The gable wall had a substantial stone corbel supporting the stone coping stones. Rotating and outward movement was noted to the stone corbel together with cracking to surrounding brickwork as well as dislodged coping stones and pediment.

Discussion

Action Wall Ties’ remediation works were designed to assist in restraining the masonry to return the integrity to the structure.

Stone Corbel Repair Solution

Remedial work by Action Wall Ties provided a cost effective long-term solution. The existing appearance of the building was maintained. Work was carried out with the minimal amount of disruption to residents and the environment.

The remediation works involved diamond drilling 38mm X 2000mm holes into stone corbels, and others into the pediment and stone coping, to accommodate installation of remedial Cintec 40mm sock anchors.

Cintec anchors installed in accordance with manufacturer’s recommendation and by Action Wall Ties’ trained certificated operatives.

Action Wall Ties serve customers throughout the South East i.e. in Kent, Greater London, Sussex and in Essex.

Action Wall Ties (AWT) are specialists in masonry reinforcement and repair, providing professional solutions to a wide variety of structural problems including issues with stone corbels, pediment and copings in Victorian properties. Contact us on 01227 721 255, or email us.

Bay window cracking dropping subsidence

Failing Victorian terraced house bay window cracking dropping subsidence – bed joint reinforcement beaming, crack stitching and brickwork repairs

Victorian bay window subsidence repair.

The subject building was a socially-owned Victorian terraced house with significant bay window cracking and rotational movement reported.

Structural engineers had been engaged and their investigation revealed the bay windows’ footing had been affected by leakage from a damaged drain and repairs instigated.

To avoid costly underpinning and new footing, the structural engineers recommended delaying any further works to allow some recovery of the underlying clay to take place.

Thereafter, they recommended that remedial works should be undertaken to include some rebuilding of the rotated brickwork at ground floor and the reconnecting and restraining of the bay window structure at ground and first floor levels with bed joint reinforcement and lateral restraints.

Action Wall Ties designed and completed the remediation works

Our remedial scheme provided a viable repair by introducing bed joint reinforcement beaming, crack stitching and brickwork repairs to reinstate the uniformity of the structure.

To the basement level of the front bay window we provided temporary support and braced the brickwork columns to accommodate the deconstruction of a sufficient amount of distorted brickwork to accommodate the realignment and reconnection of brickwork and masonry elements onto the existing footing.

Action Wall Ties (AWT) are specialists in masonry reinforcement and repair, providing professional solutions to a wide variety of structural problems including Victorian bay window cracks and movement including subsidence and other issues in the South East (around Kent and London). Contact us on 01227 721 255, or email us.