Beyond the Product: Getting Facade Specification Right from the Start
Craig Simms discusses aluminium facade specification, product selection and the details that can prevent redesign, delays and added cost.
A facade specification has to balance thermal and acoustic performance, security, accessibility, prevent redesign, delays and added cost. Those requirements don't always sit neatly together. Triple glazing may improve thermal performance, but make an opening vent too heavy. A door may need a level threshold, security and emergency egress, yet the structural opening may not accommodate them all. A large glass unit might meet the design brief, but prove difficult to maintain or replace once the building is occupied.
We spoke with Craig Simms, TECHNALs Pre-Construction Director, about the details that are easily missed and why early technical input can help avoid problems later.
What are the most common mistakes in facade specification?
One requirement is often considered without checking how it affects the rest of the facade. A window, door or curtain walling system might appear suitable, but it still needs to meet the wider project requirements. Doors may require finger-protection, security features and emergency egress, while surface finishes need to suit the building's use and location, particularly for leisure centres or coastal environments.
Glass weight can also catch people out. An opening vent may be within the system's size limits, but achieving the required thermal or acoustic performance could need triple glazing. The additional weight may then take the vent beyond its permitted limit.
A specification needs to work as a whole. One decision can affect several other parts of the facade.
Mullion and transom dimensions and interface details also need careful attention. An undersized mullion may require reinforcement or repositioning, affecting appearance and cost. Interfaces between the facade and surrounding construction need clear ownership too, preferably with input from the facade contractor responsible for delivering them.
Which overlooked detail can cause a major problem later?
The re-glazing strategy is a good example. It's easy to focus on installation and overlook how the glass may eventually need replacing.
During my time in the industry, I have seen large, fixed glazing units that meet the structural and performance requirements and were specified with internal beading. The design worked until somebody checked how a replacement unit would be moved through the building. The internal lift specified was too small.
Don't just ask how the glass goes in. Ask how it will come out again.
In this situation, the facade may then need additional mullions or transoms to reduce the glass sizes, potentially affecting its appearance, planning position or performance. Alternatively, external replacement could require cranes, specialist access equipment and permits and additional costs.
Considering re-glazing and maintenance access while the design is still taking shape can avoid these issues.
What should project teams consider when selecting an aluminium facade system?
Start with the design intent and the full set of performance requirements rather than selecting a system because it satisfies one part of the brief.
It's also worth checking whether anything is being over-specified. Another solution may provide the necessary performance while using less material or reducing the project's carbon footprint.
The lowest product cost does not always produce the lowest project cost.
Fabrication cost should only be one consideration. A solution may appear cheaper to manufacture but take longer to install. Once labour, access, programme and site preliminaries are included, the original saving may disappear.
Why should doors be considered earlier in the design?
Doors are often left until late in the detailed design, despite having to meet several competing requirements.
A project may ask for a flush threshold alongside weather performance, security and emergency egress. The door must also provide the required door clear opening once the frame and ironmongery are taken into account.
Doors can look simple on a drawing, but they are often being asked to do several jobs at once.
It may not be possible to maximise every performance with one detail. One requirement may need adjusting to accommodate the others, supported by measures such as a canopy or suitable external drainage. These decisions should involve the contractor and design team before the opening and surrounding details are fixed.
When should TECHNAL become involved in the specification process?
Ideally between RIBA Stages 2 and 3, when the design intent is taking shape but there is still flexibility to compare systems and resolve details.
We can review proposed glazing, doors, interfaces, installation methods and re-glazing strategies. Once plans are finalised, changing a system or detail may affect structural openings, planning appearance, programme and cost.
If you're unsure, ask. It's easier to change a drawing than a finished facade.
If the project team is unsure or searching for a solution, it's worth speaking to us. We may already have dealt with a similar project and help to narrow down the options.
How does TECHNAL help project teams choose the right system?
We begin by understanding the design intent and required performance, then identify systems or details that come as close as possible to meeting all project needs.
We provide technical drawings showing proposed sightlines and appearance, alongside information on U-values, acoustic performance and project-specific Environmental Product Declarations.
Specification support isn't just about product information. It's about working through the requirements and finding a practical solution.
We also flag practical constraints. For example, a structural opening may be too narrow to provide the required clear width for the door, while smoke and heat exhaust ventilation systems may require systems further free-area calculations.
Specification support is therefore about more than naming a product. It's about establishing whether the proposed solution is workable and providing the technical information to support it. We can also help connect the project team with a suitable facade contractor where required.
Are facade specifications becoming more complex?
Not necessarily, but project teams are seeking technical input sooner and asking for clearer evidence.
A proposal needs relevant calculations, test data and product information to support the performance being claimed. Our technical documentation platform, TechTip, provides a comprehensive library of information to support Gateway 2 applications and project submissions.
A recommendation needs evidence behind it, whether that is a calculation, test results or verified product information.
Material claims also need careful explanation. Recycled aluminium is not one single category. There is a distinction between pre- and post-consumer material, and the amount of post-consumer aluminium in the billet needs to be considered when products are specified.
How does the specification affect the building after completion?
The client will expect the facade to perform throughout its intended design life, including thermal and acoustic performance, ventilation, day-to-day operation and appearance.
Specification decisions also influence maintenance and end-of-life material recovery. The glazing strategy determins how units can be replaced, while surface finishes need to suit the building's use and environment.
The biggest cost isn’t the facade package itself. It’s the redesign, delay and risk that come from getting the specification wrong.
At Prince’s Exchange in Leeds, approximately 50 tonnes of aluminium have been reclaimed and recycled at Hydro’s Wrexham facility to produce new lower-carbon aluminium billets, including Hydro CIRCAL®. The refurbishment improved the facade's stated performance from 2.8 W/²K to 1.2 W/m²K and achieved an acoustic performance of 43dB. The replacement facade TENTAL system is also designed to be 95% recyclable at end-of-life, making future replacement, dismantling and recycling easier.
A specification therefore should consider the facade beyond installation. including how it will be used, maintained and eventually replaced or recycled.
Final Thoughts
Successful facade specification means understanding how performance requirements, structural constraints, installation and maintenance interact.
Early technical input can identify potential conflicts while they are still relatively straightforward to resolve, whether that means adjusting a door opening, reconsidering glass dimensions or planning for future replacement.
Craig's advice is simple: if something is unclear, ask before the design is fixed.
Do you need support with an aluminium facade specification?
Speak to the TECHNAL team about system selection, technical details and project performance requirements.
Want to see more?
You may also be interested in
Let's Discuss Your Next Project
From concept design to specification and delivery, our team can help you achieve your design, performance and sustainability goals.
Contact us