defects to balustrade wall on walkways & balconies

The subject building is a 1970s style low-rise block of domestic apartments in South East London of conventional construction with open access decks and private balconies.


Rusting of steel reinforcing bars and the handrail baluster fixings had caused potentially dangerous cracking of the balcony walls. Action Wall Ties solution for fixing the cracked brickwork involved reinforcing the brickwork. The rusted reinforcing bars and other corroded steelwork balusters were removed to prevent further cracking. New stainless steel fixings designed by Action wall ties were then fitted and the balcony walls were rendered and made good.



Detailed Case Study:

 

Defect

 

Visible cracking of brickwork and previous repairs (in a similar pattern) was noted to the inside of the balustrade ½ brick thick walls to the private balconies. 


The balconies' balustrade walls are all of a similar construction of ½ brick thick stretcher bond brickwork, with faced brickwork externally and render finish to the inside, finished with a concrete coping stone and a steel tubular handrail supported by tubular balusters embedded through the coping stones down into the first two course of brickwork.


 

Generally the external bricks and pointing were found to be in good condition with little spalled pointing and spalled bricks noted. There was visible cracking and previous repairs in a similar pattern to the internal render finish and cracking to the coping stone and first two courses in line with the embedded steel baluster

Action Wall Ties inspection revealed heavily corroding 10mm mild steel reinforcing bar set into the concrete slab adjacent to the brickwork and fixed to the brickwork with mild steel wire ties bent round the upright bar and built into the brickwork bed joint.


The cracking and previous repairs noted corresponded with the reinforcing bars built into the render finish

In line with the embedded tubular handrail baluster some cracked bed joints and dislodged coping stones was noted, in some cases the cracking continued down through the first two courses of brickwork in line with the depth of the embedded baluster. The coping stones have no mechanical fixing as required by modern day standards 


Discussion

 

From Action Wall Ties findings it is apparent that the cracking to the render finish and cracking to the coping stones and brickwork noted above are due to two generic defects, that of the advanced expanding corrosion to each of the embedded reinforcing bars and the handrail tubular baluster.

 

The brickwork has admitted moisture providing the elements together with air and the embedded mild steel resulting in expanding corrosion (ie the formation of ferrous oxide that expands several times the thickness of the metal it has resulted from) thus cracking brickwork further fuelling the process and reducing the section of reinforcing bar and effectiveness of the reinforcing bars.

 

The ½ brick thick balustrade wall’s lateral stability is dependent on the   reinforcement.  

 

The brickwork has admitted moisture running down from the baluster into the masonry resulting in expanding corrosion to the mild steel baluster thus cracking the brickwork and dislodging the coping stones further fuelling the process.

 

From our findings an engineering appraisal and remedial strategy should be adopted. The judgement is to determine the extent of the remedial works that should be instigated to accommodate maintenance program and safety issues.

 

Solution                                                                                                  

 

Action Wall Ties designed remedial works are designed to provide a cost effective, long term solution ameliorating all the defects noted that retains the existing  appearance with the minimum effect to the occupants and impact on the environment.  

 

Action Wall Ties services are available to clients in the South East i.e. in Greater London, in Kent,  in Sussex & in Essex .

 



Our proposed remedial scheme provided a viable repair with the introduction of a combination of single corded bed joint reinforcement – To remove the handrail and baluster from the brickwork, drill for and grout in AWT designed stainless steel fixings cut and weld original handrail in place



Diamond drill the full height of the balustrade wall into the concrete slab for and inject grouted stainless steel pins - remove the existing reinforcing bars from the brickwork and make good the render - drill for and resin bond stainless steel ties and make good coping stones. 


Completed balcony



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.




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