Gain more usable space in your project with Hilti rainscreen systems.

Space – the most valuable asset to your project

Space is scarce. Ever since society started focusing on services, more and more people are moving into cities and demand for space is increasing exponentially.

This pressure means that we build on less favourable soil conditions - consider where 50 years ago there was a swamp, we now see tall skyscrapers, defining the city panorama. Every inch of the building height is meticulously calculated and evaluated with its costs and benefits, putting huge pressure on engineers to fit everything inside in favour of living space. Just consider the improvements in fire safety, with increased requirements for escape routes, elevator shafts, staircase widths, number of escape routes, sprinklers and more. All of this must fit into your floor plans while investors expect increasing return of investment based on sellable or rentable space. This goes hand in hand with land scarcity making space the most luxurious attribute of your project.

There are several lessons learned from the COVID pandemic related to the design of hospitals. We need to move from large open space patient wards to individual rooms for each patient.

ICU units need to have more empty floor space even beyond normal capacity, to be prepared for quick expansion in crisis times.

Façade defines wall properties, it’s not just about the “U”

Façade is a highly important architectural part of any building. It accounts for the first impression and impacts memorability strongly. Apart from the visual aspect of a façade there are usually several more requirements: 

Passive fire safety of the façade as a whole, for acoustics performance (See more in our previous article)

Currently all new buildings must meet U value requirements as stated in the Approved Document L Conservation of fuel and power (section Six for Scotland). The various benefits of improved thermal efficiency are well known, but usually complex to directly quantify in the early stages of a project. It requires a 3D model of the object with all thermal properties of the envelope and HVAC systems simulated, followed by an evaluation over a determined period of time to measure savings in energy and costs.

U value can be calculated, but for example air tightness is just based on estimations unless measured on-site, but then it’s usually too late and costly to fix those issues.  More complex façade with more connections, details, and windows means more potential air leaks. And while models can predict future savings, reality also shows that effective outcomes depend heavily on the quality of the installation thus making the models useless.

Nevertheless, there is another way to look at thermal efficiency of exterior walls and bring extra value to your project. One that is much simpler and easier to determine.

Example

What you see above is the floorplan of a three story building. Down below we simulated what would happen to the usable area of this building with each of our Hilti substructure systems. Everything is the same except the substructure. So the cladding, insulation type, base wall material, exterior dimensions and lastly target U value = 0,2W/m2K is all the same.

Just a change in the substructure drastically impacts the usable area without changing the exterior dimensions.

MFI - basic Eurofox substructure system suitable for all applications. Bracket is made out of Aluminium offering better insulation that steel. Optional is the thermal brake isolator at the base.

MFI with 1 395m2 is used as baseline comparison in our examples below.

Fox V – Newly developed system with improved static performance (higher load bearing values – less brackets per m2 needed > less thermal bridges), thermal performance, pre-installed isolator from production and much more.

Check out the video here

S2S – slab to slab system, brackets are fixed only on slabs in each floor with vertical profiles spanning the height of entire floor. Ideal when base material is weak for anchoring e.g. refurbishments.

VTR – is a stainless steel system, offering great thermal performance as stainless steel itself has about 10x lower thermal conductivity than aluminium, so no thermal break is needed.

Fox T – Eurofox bracket system with best thermal performance. Thanks to its composite section in the middle it negates thermal bridges to a minimum and thus requires less insulation material while achieving the same U-value. Fox-T was ETA certified in 2021.

Without changing outer dimensions of building we can gain significant amount of space inside just by choosing correct façade substructure.

*Price per m2 is based on median price in UK 2020 for developments. It can be significantly higher based on location and purpose of the building!

A few millimeters can mean thousands of £'s

Selecting the right substructure can save you millimeters, this translates to square meters and can bring literally thousands of pounds of extra value on your project. In our example we looked at a simple three story building, but if you use the same logic on six, seven or even ten floors, the effect is even higher and the value of gained space goes into hundreds of thousands of pounds.

The same applies to residential development, houses built in a row after using Fox-T could possibly add an extra house at the end of the street without shrinking the living space or the other way around you can increase the living space in each house.

33m2 gained on our example just by choosing Fox-T substructure over standard façade substructure brackets.

Overview of Hilti substructure portfolio both for vertical and horizontal applications

Every substructure system and bracket has its purpose and it’s designed to meet different needs and requirements of our customers. Do not hesitate to get in touch with our engineers to find the right solution for your project and needs.

Our comprehensive service offering includes:

-    U value calculation and wall thickness optimisation    

-       Cooperation with multiple cladding suppliers

-       Cooperation with insulation manufacturers

-       Cooperation with installers

-       Design and supply of façade substructure

-       BIM design and support

-       Façade fire safety consultation

-       Structural design

-       Sound resistance, calculation of Rw (C; Ctr)

To get directly in touch with our façade consultants, please send us an email

If you have any questions related to the article or our rainscreen solutions and services, please post your question on Ask Hilti

For latest news in engineering solutions and innovations follow us on: LinkedIn, Instagram and Twitter

This article is part of ongoing series dedicated to ventilated façades. Find more here