Roofing 1,585 views Oct 25, 2017
Sweat the small stuff for thermally efficient roofing

Small details pay big dividends in roof specification. As a building’s first line of defence and prominent thermal feature, a roof must maintain long-term, maximum performance. Therefore, every aspect of its installation and insulation should be considered to ensure t remains watertight, problem-free and energy-efficient during its lifetime. Andrew Rowley, Senior Designer at Gradient, the UK’s leading supplier of tapered roof insulation, highlights a few seemingly minor roofing issues, which if not addressed correctly, could result in major problems following installation.

By failing to prepare, we prepare for failure - an oft-repeated phrase which applies very favourably to successful roof installation and its thermal performance. In the UK, homes are responsible for 27% of carbon emissions, a statistic that requires serious attention, especially as our government committed to reducing the country’s CO2 emissions by 80% by 2050 as part of the Climate Change Act. To improve the thermal-efficiency of buildings old and new, perhaps we’d be advised to adhere to another well-known phrase - prevention is better than cure.

Tapered and tailored to suit 

The specification of bespoke, single-layer tapered roofing solutions can help alleviate risk when it comes to insulation. This outcome is easiest and best achieved in conjunction with companies such as Gradient which works closely with customers on the design and manufacture of a suitable system for a wide range of roofing applications. Placing the insulation process - from start to finish - into the hands of highly-experienced and skilled professionals not only maximises control standards in roof design, manufacture, performance and sustainability, it results in a better-conceived flat roof which is improved in value, performance and complies with all relevant legislative standards.

Gradient is able to supply specialist technical support to provide customers with flat roof solutions - whatever a roofing project’s stage. However, it’s fair to say most problems occur when clients neglect to engage such company’s at the very start of the roof specification process which minimises the risk of future problems. The close proximity of door thresholds to roof decks resulting in underperforming U-values is a common issue. It’s an oversight which can lead to water-ponding and possible insect infestation, but can easily be avoided with early involvement from the roof insulation manufacturer.

In such cases, a tapered roof insulation scheme can be applied, but the thermal performance will not be as good as it ought to be due to the aforementioned fault at the design stage. Encouraging developers to consider roof insulation sizes long before they start casting concrete is key to trouble-free roofing. When a building’s shell and certain fixtures and fittings are in position before roofing issues have been fully-addressed, it can often lead to height limitations being imposed on the insulation installed. Thus, flat guttering, the same thickness as the insulation is seen as a solution. Whilst this might be seen as a perfectly acceptable system for installers, developers would quite reasonably prefer a completely run-dry roof on which water is pushed to all available outlets.

Mind the gaps

Constraints on insulation height will sometimes rule-out the use of a fully-tapered roofing scheme, therefore a compromise on a particular roofing detail may have to be reached. It could lead to a roof design which doesn’t necessarily reflect best practice, but is nonetheless the best scheme with all factors considered. Compromise can take the form of a lower U-value, or the installation of a hybrid roof scheme in which insulation is applied below the deck. The latter solution is not ideal, as condensation is often a by-product. However, roofing firms such as Gradient are able to carry out calculations for a hybrid roof that will eliminate the risk of condensation.

Whichever roofing insulation specified, its performance is only as good as the installer. Selecting a proven contractor to carry out installation work is vital - a task becoming more challenging by the day with Britain facing its biggest skills shortage for a generation, particularly in the roofing industry. If a contractor omits to fully-tackle air gaps, for example, in a perfectly-designed roof, the potential for condensation remains.

Strip to reveal

For developer, contractor and customer, time is money in the construction industry. With budgets being tightened across the sector as uncertainty over Britain’s post-Brexit future remains; so ever-tighter deadlines must be met. However, quality must not be lost in the rush to reach the finish line. For refurbishment projects in which an existing roof is overlaid, Gradient is able to design a tapered scheme, with surveys made all the easier due to the visibility of the building’s falls. It’s part of the company’s service to carry out the same assessment when a roof is stripped to its deck. Time restrictions will often lead to contractors refusing the offer of a second visit, even though the stripped roof could reveal a deck to be damaged or uneven and in need of a rethink as to how the insulation should be applied to improve its long-term performance. Again, the answer is good preparation. Building extra time into a roof’s installation before installers arrive on site will help avoid unseen issues which may crop-up as the process continues.

Quality roof insulation, which protects against the ravages of the elements and time, as part of a long-term, waterproof system, doesn’t arrive by accident - it’s most definitely the result of excellent design and installation.