Different use of roofing felt and welding track

For many, the difference between roofing felt and bituminous membranes is not always completely clear. You can read in this article which different application possibilities arise for both types of bitumen board and where each of them benefits.

Differences between bitumen roofing membranes and bitumen board

The tar paper has its name wrongly: New "tar paper" (roofing felt) contains no carcinogenic tar for decades. It is soaked as well as the Bitumendachbahn with bitumen.
Bitumen is harmless to health.

The main difference between a bitumen roofing membrane and a tar paper is the thickness. The thickness of the material can already be recognized by the product name:

  • Roofing felt R333 is 333 g / m²
  • Roofing felt R500 is 500 g / m² heavy, therefore thicker
  • Roofing felt V13 weighs 1300 g / m² and thus already a bitumen roofing membrane

The letters in front of the numbers indicate the type of carrier layer. "R" stands for raw felt, "V" for glass fiber fleece. For carrier layers made of glass fiber fleece and a corresponding thickness, the trade name is often still "roofing felt" or "roofing membrane", due to the strength is technically but already a bitumen roofing membrane and no longer to roofing felt.

Sanded roofing felt and roofing membranes

Both roofing membranes and roofing boards can be sanded. For this purpose, either fine gravel or coarse-grained sand is rolled into the uppermost layer in order to increase the abrasion resistance of the roofing felt.

Particularly high-quality roofing membranes or roofing boards can also be "delivered". Instead of sand or gravel shale splinters are then rolled.

Sanding is available both for bitumen roofing membranes and ordinary roofing membranes. Unbedandete roofing membranes are often referred to in the trade as "naked" or "blank".

Shipped roofing felt V60-S4 is often referred to as "elephant skin".

Processing differences

Roofing board is always laid loose. It can be nailed (with special roofing nails) or fastened with staples.

Roofing membranes, on the other hand, are usually cold glued (less frequently) or welded to make them completely watertight even at the joints and seams. Even cold-adhesive bitumen roofing membranes are commercially available, but are rarely used, as they are significantly more expensive.

Different applications

Roofing boards are rarely used as the top layer of a roofing. Due to their low thickness and the less resistant carrier layer, they are significantly less durable than the thicker bituminous welding tracks. They would therefore have to be renewed more often.

As the sole cover, they are only used for small tool sheds or very small garden sheds. There they are the cheapest Eindeckmöglichkeit. As a rule, the coverslipping then takes place in two staggered layers, the uppermost layer being sanded and the lower one being bare.

If a higher durability and water resistance is required, usually used for the top layer of a bitumen welding (sanded or delivered) used. In summer houses can also be covered with bitumen roof shingles, which are particularly durable.

Although a coat with a bitumen thick coating would be a way to make conventional roofing durable and completely waterproof, in practice this is not done due to the high cost of cheaper roofing felt. In contrast, the use of a bitumen-based topcoat or coating against weathering (higher UV resistance) is occasionally carried out.

Video Board: Building a Lean To - Installing a Shingle Roof and Double Doors (Part 3)