The survey that has been commissioned and provided by Edge has found failure of the Joltec paint system in two ways. Firstly the Joltec membrane is blistering and lifting away from the tiles underneath. Secondly the coating itself is starting to break down and is no longer stable. The edge report estimates that within any 3m squared area 5 to 10 patches can be identified where the Joltec is detached from the tiles.
Further to this the report describes Joltec perforations where the system is fully breached. The report describes this situation arising on all elevations at all levels were obvious multiple perforations have been caused by impact. It is thought this impact is from the window cleaning cradle activity.
We have discussed the identified universal surface crazing with the Jolted manufacturer and they have advised that this is a breakdown of the Joltec itself and it is unlikely to still be providing an effective barrier to the elements.
The survey has in addition identified areas where the mosaic tile structure is live. By this we mean that it is no longer fully bonded to the rendered layer beneath the mosaic tile. I have attached a section from the original design plans that shows how the build up of the walls is constructed.
In response to the statement that 80% of the wall covering is in good condition. We have not assessed the amount as an area calculation. However the defects across the building are universal. If 20% of the building has failures and this 20% is distributed evenly over the building, which we believe it is, this gives rise to a patchwork of failure throughout the building on all levels and all elevations.
We do not know at this stage how difficult the tiles will be to remove from the underlying render. It is likely that the strength of the bond between the tiles and the render beneath will vary considerably. It is not a fair assumption that the experience of removing tiles internally will match the experience of removing them externally. It is likely that the removal of the tiles will be disturbing to a degree and a method statement will be produced to makes sure that all tiling removed from the face of the building is carefully controlled to make sure it cannot fall from the platform from which operatives are working.
The mosaic tiles are fixed to a sand cement render. This type of render has often been used as the final protective finish to a building. It will not on this basis be damaged by short term exposure to the elements. The new render system will have multiple layers and we will take advice from the manufacturer regarding the conditions in which the layers can be installed. The system is designed for external application and we do not anticipate normal weather conditions for South East coastal regions to be prohibitive to the installation of the system.
We have reviewed the fixing method of the original heads and trims of the windows and the balconies and based on this knowledge I cannot see any way that these could be loosened through the removal of the tiles. Newly installed windows may be fixed alternatively. However, we will be asking the contractor to confirm the method for removal of the tiles and we will require them to demonstrate how they will achieve this without causing damage.
It is regrettable that the Joltec as an application cannot be repaired, previously the re application of further coats of Joltec have extended the life of the external façade. We are advised by Ronacrete who manufacture the Joltec product (albeit the name has now changed) that they do not think a further coat simply applied over the old will be effective and the new top coat could start to fail soon after its application since the condition of the underlying coats is now so poor.
We do not believe that the Joltec can simply be removed from the mosaic tiles. If this were possible it would still leave a significant number of areas where the tiles are starting to de-bond from the render beneath. This is a situation that will continue to get worse and will not be halted by the application of further coats of Joltec.
Our view is that given the progressive failure of the various layers of the building, if a further liquid coat is applied to the outside of the building, failures in this coat will become apparent in a short period of time and perhaps within 1 year.
We believe that if a further short term liquid application is carried out in 2015 this will give rise to further remedial works being necessary perhaps within a 3 year period. As the underlying layers of Joltec continue to deteriorate the additional coats will become less effective and the intervals between required coats applications will become more frequent.
It is our view that now is the time to carry out a long term solution to the continuing deterioration of the external envelope of the building. Our proposal when considered from a whole life cycle perspective will be cost effective over a 15-20 year period. This is because the access requirements for each occasion that the building is worked on forms a considerable part of the cost of the works. A rendered solution should leave the parts of the building currently covered by mosaic tiles maintenance free for 20 years with a robust clean and presentable finish.
We are happy to consider and review any other options that are presented.