Façade refurbishment: Creating a bespoke strategy
Hans Jansen, Lead Concept Design at Permasteelisa Group, examines the factors that impact refurbishment options, and the steps towards creating a bespoke, reliable strategy.
Looking at options
Our FaçadeCare teams have excellent experience in façade condition surveys – finding drawings and information around the existing façade, carrying out visual and physical assessments to calculate the remaining service life of a façade and its components, and assessing the logistics around replacement, including access and safety. Surveys help to establish some of the key parameters around refurbishment options.
If, as with Citi Tower in London, it is a façade that we originally built, after 2000, digital files make it much more straightforward to carry out a refurbishment. With all the die drawings available with this project, we are connecting the old façade with a new façade system 1:1, cost effectively, with watchmaker’s precision.
The deep understanding of the original façade, designed by Permasteelisa or others, that a survey gives us assists in determining scenarios for refurbishment, and we assist our clients by creating an overview of the performance and a SWOT analysis of the different refurbishment options, often coming up with new possibilities not initially considered by the design team.
By assessing the access logistics on site (often the real challenge!) and the programme for disassembly and installation, we can also assess potential timelines – in the end our clients want to refurbish as quickly as possible.
Providing upfront certainty
Investigation of the existing façade, a potential survey and the offer for different refurbishment options, including price, design solution, preliminary method statement and programme, are all part of our tailored Pre-Construction Service Agreement (PCSA), giving clients upfront certainty, so that they can make informed decisions.
This PCSA is followed by a contract stage in which we work with samples, visual mock-ups, performance mock-ups, benchmarks and off and on-site testing, to ensure the new refurbished façade is compliant with the specification. From this we can declare the performance, providing a warranty on the executed works.
Minimum intervention
When a building is in operation, has a multi-tenant use, no tenant lease break or is privately owned, a Protective Planned Maintenance proposal (PPM) combined with a cleaning and maintenance contract often provides the best approach to extending the service life of a façade. A PPM provides an initial condition survey, followed by a minimum intervention strategy to keep the façade in optimum shape for the coming years.
Reglazing and upgrades
The typical service life of insulated glass and external gaskets is 25–30 years, and so after a 25-year first lease, for example, building owners may be planning a first large-planned maintenance, taking replacement needs into consideration. This may well coincide with a lease break, whereby the owner is reevaluating their value proposition to attract new tenants, and a façade’s thermal insulation, solar gains and aesthetics (colour, coatings) are usually also under consideration at this point.
In many instances, replacing materials that are at the end of their service life, such as glass and gaskets, is a logical choice, both for improving thermal efficiency and solar gains. This often allows the retention of the framing, finish, insulation and opaque areas. For potential new tenants, this option provides both the certainty that the façade performs, and that there is no large refurbishment work planned for the next 25 years.
With heritage buildings, the challenge often lies in improving the façade whilst maintaining the original appearance. For Koningskade 4 in The Hague, for example, we replaced a 60-year-old gasket holding the glass and replaced it with an identical looking aluminium framing solution. This intervention improved the performance, safety and reliability of the façade, while maintaining the appearance and making it futureproof again. These are challenges we love to take on.
The carbon puzzle
We have recently developed our in-house carbon payback tool to see the impact of different scenarios on embodied versus operational carbon. We use this tool to look at all the relevant R-strategies (refuse, reuse, repair, refurbish, remanufacture, repurpose and recycle) and come up with potential solutions. We carry out this analysis together with the client’s design team, looking at the impact on a building system level; sometimes a little more carbon investment in the façade can save operational or embodied carbon on a building scale.
Vertical access
The logistical challenge with replacing façades is that old glazing needs to be taken away, and new façades installed, and often this is carried out without the equipment available on a new project, such as scaffolds, tower cranes, monorails, gantries and mast climbers, and so for every job we work together with the main contractor and/or client to come up with the right approach.
At Citi Tower for example we decided to disassemble panels completely on the floor after their removal and bring them down in small parts with the goods hoist, whilst bringing up new panels using a purpose-built external lifting rig that could take up crates, containing complete façade units.
Where possible, we reuse existing façade materials either in the same, or other projects. 1 Triton Square and Koningskade 4 are two such examples.
Read more about circularity in façades here, and our different refurbishment services here. And for queries into our refurbishment service, please get in touch at h.jansen@permasteelisagroup.com.