Save Time and Money While Improving Thermal Performance

Save Time and Money While Improving Thermal Performance
– Why High-Performance Insulation Just Makes Sense.

Sustainability has never been higher on the agenda and every industry is being asked to play a part in the road to net-zero by adopting new technologies and adapting working practices.

The construction sector is no exception and developers are continually under pressure to realise ambitious targets and boost the overall performance of buildings.

One of the easiest ways of improving building performance is to address heat loss, especially via the specification of high-performance roof insulation. It is now not uncommon to encounter requests for an inverted roof achieving 0.13 W/m²K rather than the previously typical 0.15 W/m²K target U-value as developers scramble to find the most cost-efficient mechanism of satisfying the demands of Part L of Building Regulations.

A single layer of Ravatherm XPS X ULTRA 300 SL was used to achieve a 0.12 U-value at 22 Hanover Square in Mayfair, London

Improving Thermal Performance

The challenge facing contractors is that, with most products you will need to use multiple layers of insulation to achieve this level of performance, and this has several downsides. There are products on the market that allow you to meet these exceptional levels of thermal performance with just a single layer, such as Ravatherm XPS X 300 SL or next-generation extruded polystyrene (XPS) Ravatherm XPS X ULTRA 300 SL insulation.

By avoiding double-layering, roofing contractors are able to halve installation time and therefore the quantity of labour. With wages for a gang of six roofers easily exceeding £500 a day outside of London, the reduction in labour costs can be significant! Not to mention that the widespread labour shortages across the construction sector due to the impact of the pandemic and Brexit mean it is more important than ever that we deploy available labour efficiently. Plus, the ability to do tackle more projects without increasing manpower requirements is a nice bonus for any contractor.

In addition to creating more work at a job site, layering makes it considerably harder to perform an accurate calculation of a roof’s U-value. When multiple boards are being used, it is essential to account for the impact of the thin layer of water that will naturally accumulate between the layers – water will always penetrate to the insulation on an inverted flat roof, even with the use of the all-important water flow reducing layer. To account for this, correction factors for a double layer of insulation have been outlined in BBA Bulletin 4 Inverted Roofs – Drainage and U value corrections, but no factors are available for triple-layer buildups. There is no recognised calculation method or long term test data for triple layer installations

Without a recognised calculation method or long-term test data to provide surety, it is a risky proposition to proceed with a triple layer insulation buildup. This risk combined with the significantly higher labour requirements makes it illogical to proceed with a triple layer of standard insulation when next-generation XPS insulation can do it in a single layer and still hit ambitious U-value targets such as 0.10 W/m²k.

Space is always at a premium on a construction site and finding places to store materials can be challenge.

High Performance Insulation

Fewer layers also mean a lower overall volume of insulation and this brings several benefits. While 550m³ of double-layered standard insulation would typically achieve 0.15 W/m²K on a 2500m² roof, specification of the higher-performing Ravatherm XPS X 300 SL or Ravatherm XPS X ULTRA 300 SL would require 500m³ or 438m³ respectively – that’s the equivalent of up to a couple of artics worth of insulation! In other words, by using higher performance insulation you can reduce the number of necessary vehicle movements around an already busy site and all of the time that would have been spent unloading and transporting the boards to their final install location. Finally, considering the emphasis being placed on sustainability, it would be remiss if we also weren’t to consider how this also reduces the embedded carbon of a building.

By reducing the volume of insulation needed, you can cut the time spent unloading and moving materials around site.

As we all know, space is always at a premium on a construction site, and by the time comes to installing the roof finding places to store materials can be a real challenge, especially with city centre developments. By reducing the volume of insulation going into a structure, we also reduce the amount of space needed to store materials ahead of installation. Why not try and keep the site manager happy while you’re at it?

Finally, by specifying high-performance boards, we can reduce the overall thickness of the insulation. This makes it much easier to ensure level thresholds and keeps balustrade walls at a lower level, therefore making the whole roof installation process less arduous alongside making Approved Document M compliance a walk in the park.

When it comes to specifying high-performance insulation, you’re not making a compromise. You’re choosing a product with exceptional thermal performance which will save you time and money while knowing you can sleep soundly, assured that you’re playing your part in the sustainability revolution.

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