Are Modular Roofs the future?

// the building envelope

David Patrick, head of marketing at Redland discusses the impact of modular roofing systems for the UK.

In the run up to the general election Brandon Lewis, the recently reappointed Housing and Planning Minister, was very vocal about his desire to see the industry adopt new and innovative methods of building houses: expressing a belief that MMC offers benefits in terms of quality and efficiency. Furthermore, they continue to evolve.

Proponents often point to speed of build as the primary benefit; those that speak out against it, however, refer to the potential negative impact it will have on housebuilding in the long term.

Looking back over the years there are plenty of instances of ‘system’ building or prefabrication leading to poor standards of construction, especially when the Government of the day accelerated housebuilding in the post-war years.

For many people offsite construction relates solely to the external and internal walls of a property, but recently the concept of modular construction has expanded to also encompass the roof of a building. The roof is built in sections in factories and arrives on site fully equipped with components and tiles ready to be installed and pieced together.

Similar to offsite construction of walls the advantages of modular roofs focus very much on speed. On jobs when time is of the essence the roof can be installed and made weathertight far faster than if traditionally constructed. This is crucial on projects when the climate is working against the contractors.

One such project saw existing stock in the Fife region of Scotland converted into new housing and flats by Fife County Council and Sharp Homes. The area is subject to harsh weather conditions – which makes achieving a dry shell a priority.

Logistics plays an important role in the success of any project. A poor or overly complicated supply chain can prove to be highly detrimental, a project can fall behind schedule and consequently complete much later than planned resulting in escalated costs. This risk is reduced with the use of a modular roofing system.

The units, once complete, are loaded on to trucks, driven to site and craned into position. This simple and straightforward supply chain greatly lessens the chance of product being damaged.

As always when it comes to roof construction the issue of health and safety needs to be considered. There are always dangers when constructing roofs in the traditional manner; falls from height were the most common cause of fatalities in the work place in 2013 / 2014, accounting for 29% of fatal injuries. Modular construction virtually eliminates this danger as assembly is carried out at floor level before the units are craned into place.

As with all new innovations there are negatives to modular roofs.

The new code of practice for roof slating and tiling, BS 5534, came into effect in February this year and outlines improvements to the fixing of tiles. Tiles are fixed to the roofing modules prior to leaving the assembly plant, but can become damaged during transit on route to site. In the past this would not be a severe issue as tiles could be easily replaced. Now though, the tiles are fixed in accordance with the new code of practice they are much harder to replace and can take a significant amount of time which consequently delays the completion on site.

There is an argument also that roofers are skilled tradespeople and that the trade could suffer if modular roofing was to become a mainstream practice. On the other hand, these skilled workers will still be employed to construct roofs, but would not be required to work at height which is a major advantage in terms of health and safety. 

Housebuilding is a traditional sector and perhaps Brandon Lewis is correct in saying that we need to be more innovative and employ different build methods if we are to build more houses. Modular roof systems do solve many common construction issues – anything that stops the weather from wreaking havoc with project plans and budgets can only be a good thing. However, we are not an industry that adopts new innovations at speed therefore I am not convinced that this method of roof construction will become common practice in the near future, but it does definitely have a place in the market.

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