A number of trends are emerging in roof design, reports Matthew Beecham. First is the sheer size and sophistication of the products. Panoramic sunroofs stretching the length and breadth of a vehicle are becoming increasingly popular on both sides of the Atlantic. Second, roof systems are fast becoming part of a car’s identity. Third, roof systems are developed along modular lines with suppliers hoping that car manufacturers will begin standardizing roofs to allow a variety of pre-sized modules to fit the openings.

Thomas Schütt, director of product management, roof and body, Webasto agrees that there is indeed a comeback of roof systems in cars.  He told us:  “The modularisation should help to increase take rate even more in the future. We can confirm the trend to use the panoramic roof as a design feature of the car. End-consumers see especially the rail-to-tail design of panorama roofs and the features “fresh air” and “natural daylight” as an ongoing trend and a requirement for future car models. Modular design is a general trend in the automotive industry as the diversification of vehicle brands continue. This is a trend for supplied parts, too.“

As far as sunroofs are concerned, Schütt says this in direction of bigger transparent areas and bigger openings in order to bring higher comfort to the end customers. “This is accompanied with the need for lighter materials, such as polycarbonate. We are already producing a polycarbonate roof system for the Smart Fortwo. This fixed transparent module has a size of 1.2 m2 and a weight of just 7.6 kg. One special trend is also the integration of solar cells in the roof skin directly or in the sunroof panels. Webasto has been delivering solar sunroofs to the market for more than 20 years.”

Meanwhile, consumer demand for retractable hard-tops (RHTs) remains strong. Walter Pecho, vice president, R&D, Webasto-Edscha Cabrio, Webasto Group, believes that there was a lot of excitement and popularity about this type of convertible roof system when RHTs started to enter the market about seven years ago. “Currently we see with regards to the quotations from OEMs that this has cooled down to some extent. Nevertheless, RHTs will have a high percentage of convertibles also in the future. But they will definitely not replace soft-tops. We also have to acknowledge that the introduction of RHTs increased the community of convertible car drivers. RHTs are interesting for those customers who feel safer under a metal roof.”

We are also seeing a trend towards roof modules with integrated opening systems (multi-panel, etc) as modular technology supports the trend towards top-loading assembly processes on the carmaker’s assembly line.  This itself gives potential for the use of various roof options on one body interface.

Magna CTS engineers point out that roof options like panoramic roofs and textile folding roofs are often assembled to the car as top-load systems.  They told us: “These roofs are typically a remarkable styling element.  Bottom-load panoramic roofs will stay in the market for a number of models.”

In terms of the market outlook for roof modules and whether we could expect to see carmakers outsourcing more roof modules, Magna CTS engineers report that, in the last few years, a small trend has emerged of insourcing the development and production of roof modules due to the economic crisis.  “However, with the growing market and vehicle sales, more roof modules will be outsourced and OEMs will focus on their core business again. Another trend will be modular kits that make use of carry-over parts between the panoramic roofs of sedans or estate vehicles, or between C and D class convertibles.”