Raising the roof

Could the altitude clause in BS5534 leave some contractors high and dry?

BS5534:2014 highlights the role of a roofing underlay’s wind uplift resistance in protecting against stormy weather and preventing costly damage. The considerations it outlines (based on a combination of meteorological, geographical and building physics data) not only establish the minimum standards in the new code of practice, but are also essential to long term peace of mind.

However, while much is being made by various underlay manufacturers and suppliers of achieving BS5534:2014 compliance, the picture may not be quite so straightforward – especially when you consider that a key part of the revised standard refers to altitudes not greater than 100m – and that large areas of the UK are at often surprising heights above sea level.

For example, one might expect parts of Cumbria, Wales and Scotland to exceed that benchmark… but how about Milton Keynes? Or swathes of Essex, Surrey and Nottinghamshire? Could this factor expose some unsuspecting developers and contractors to unnecessary risk and make them vulnerable to falling short of the code – and therefore potentially liable in any insurance claims?

Many parts of the UK are at an altitude that exceeds the 100m above sea level benchmark stated in the new BS5534:2014 code of practice, which may affect compliance and requires very careful choice of roofing underlay.

With world weather looking increasingly unpredictable (and litigation on the rise) anyone specifying a membrane would do well to ensure that, like their project’s roof, everything is covered by a membrane with proven reliability and compliance with all conditions, altitude included.

All underlays are required to clearly state, in literature, certification and on roll labels, the declared wind uplift of the material, and on this basis, the end user can determine the suitability of the material for the site’s location. BS5534 splits the UK into 5 zones, and to be “fully compliant” at a batten gauge of 345mm, the following test parameters must be met:

• 1,600 N/M2 when a well sealed ceiling is present
• 1,900 N/m2 when no ceiling or no well sealed ceiling is present
• 2,350 N/M2when no ceiling or no well sealed ceiling is present and a permanent dominant opening is present on an external face of the building.
But, is it that simple? The new standard also requires compliance with the following conditions:

• Ridge height not greater than 15m
• Roof pitch between 12.5° and 75°
• Site altitude not greater than 100m
• No significant site topography

Clearly, comprehensively meeting all the requirements of BS5534:2014 could prove challenging for contractors also looking for a reliable, easy-install, trouble-free solution. Fortunately, however, there are products which allow unrestricted use anywhere in the UK, in all building characteristics and under all site conditions. This allows contractors to be confident that they in are full compliance, not only with the code, but with all the weathering and thermal performance expectations of an advanced breather membrane.

Your News

If you've got a story that would be of interest to Builder & Engineer readers, send us an email

Features

2017-05-31 13:33

The rate of Insurance Premium Tax (IPT) will rise by two per cent on June 1 to 12 per cent on all non-exempt transactions. Martin Bennison, managing director at construction finance firm Ultimate Finance, explains what this means for UK construction companies.

2017-05-25 08:41

Building Information Modelling (BIM) is growing in popularity and is now mandatory for centrally funded public-sector projects. Experts and the curious are gathering more and more frequently at dedicated congresses, exhibitions and workshops. Many people are now asking: Where does the UK stand on the issue of BIM and the digitisation of the construction industry?

2017-05-10 10:47

Opening site doors to more females is vital to plugging the construction skills gap, reports Claire Cameron

THE construction industry continues to be plagued by a well-documented skills gap with some suggesting the shortage could get worse before it gets better.

2017-05-08 14:27

If you work on a building site, are self-employed or have a zero-hours contract, you might be surprised to know you work in the ”gig economy”. This is the economy characterised by temporary work and irregular hours, pay and working conditions.

2017-03-29 10:31

Jeremy Gould, VP sales Europe, TomTom Telematics, discusses how technological developments in vehicle telematics have opened up new workflow management possibilities for the construction industry

2017-03-21 09:31

With the demand of oil increasing, it’s estimated that the Earth will reach its full capacity for oil consumption at some point within the next 20 years. This is despite the production of oil decreasing, and the construction industry is no exception to this, reports Niftylift.

2017-03-17 10:55

With construction firms leading the way in drone technology, Claire Cameron takes a closer look at how unmanned aerial vehicles (UAVs) can be used onsite

2017-03-07 16:20

While the physical safety of workers is prioritised on construction sites, mental health is often overlooked, reports Claire Cameron

Free E-newsletter Sign-Up

Sign up for our free e-newsletter

Looking for a company or service?