Roofing board: Guidebook


Roofing board is a proven solution for roofing to garage or garden shed dar. The material is inexpensive, easy to work and is ideal for self-laying.

What is roofing felt?

Roofing felt was already described more than 150 years ago and has since been used for covering mainly flat roofs, since the roofing felt requires a not so great inclination angle of the roof, as is required for example when tiling with bricks. Previously, the roofing felt was made of cardboard soaked in tar, which was coated on one side with sand or similar material for better durability and strength. After the harmful effects of tar have become known, only bitumen is used in Europe for the production of roofing felt. This is a petroleum product, sticky, viscous and very dense. Therefore, today only used bitumen roofing board has excellent sealing properties - provided that it has been installed professionally.

Laying roofing felt

Roofing felt can be laid single or double, and there is also a distinction between gluing and welding. The optimum sealing is achieved by welding, the roofing felt is referred to in this case as welding cardboard. In any case, the roofing felt, which is available as a roll product and as a shingle, must be designed to overlap. First, lay out the entire surface, paying attention to a sufficient overlap of at least 10 centimeters. Before nailing, at least the upper edge of the stitching is coated with adhesive or putty. Then the roofing felt is nailed, using galvanized cardboard nails, which should be placed at a distance of about 10 centimeters. A final coat increases the life expectancy of the roofing felt and thus of the entire roofing.

Worth knowing about roofing felt

While in the former GDR the roofing felt was also used to cover residential buildings, today the material is generally used only for sealing or covering garages, outbuildings such as garden sheds, sheds or stable buildings. In fact, wrongly, because the professionally laid roofing felt has a long service life and can be given a very appealing touch by paints that are available in a variety of shades. Roofing board has an uncoated, smooth bottom and a coated top. From the name you can see which coating and what quality of the roofing felt is. The name Roofing Board "r 333" states that the material has a weight of 333 g per square meter and was reinforced with raw felt. The term roofing felt "V 13" refers to a roofing felt, which is considerably more stable at 1300 g per square meter and used for processing glass fleece. It is therefore advisable not to pay attention to the favorable price when making the purchase decision, the quality ultimately determines the life of the product.

Prices for roofing felt

The prices for roofing felt vary greatly depending on the design and purpose. The pure nail board, which is used for example for the covering of garages or outbuildings, is already available for a price per square meter of about two euros. However, in the case of a product of this price range, further protection against moisture must be applied, especially if the carrier consists of raw felt. The necessary coat of paint increases in the sum again the square meter price. Therefore, critical comparisons are necessary, the expert advice by an experienced roofer makes sense.

Roofing board: Guidebook

FAQ - 💬

👉 This Guide is intended to give a relatively brief introduction to roofing, to weigh pros and cons of various materials that are not available in other reference documents, and to provide some suggestions for enhancements beyond systems that simply comply with code and warranty minimums.

👉 Most other roof system requirements in the building codes (i.e. IRC or IBC) focus on weather protection, structural performance, roofing materials, and installation.

👉 Manufacturer Review: Require the roof covering materials manufacturer to review the specification and drawings and advise in writing of their acceptance thereof, or to submit in writing their concerns and recommendations to resolve these concerns.

👉 The thickness is often chosen based on the need for the board to provide integrity over the roof deck, such as at flute spans on steel roof decks. The type of substrate board should be chosen based on the roof-deck type, interior building use, installation time of year and the cover material to be placed upon it.


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