Spændbåndsbjælker

Spændbåndsbjælker, also known as tie beams or collar beams, are structural elements used in construction, particularly in roof framing. Their primary function is to resist outward thrust generated by a sloping roof structure, preventing the walls from spreading apart. They are typically horizontal members placed between opposite rafters, usually in the upper third of the roof span. When a roof is loaded with snow or wind, the rafters push outwards against the supporting walls. The spændbåndsbjælke counteracts this force by acting in tension, effectively tying the rafters together and channeling the outward thrust downwards. Without adequate spændbåndsbjælker, a roof could potentially collapse outwards. The placement and size of spændbåndsbjælker are determined by factors such as roof pitch, span, and expected loads. They are a fundamental component in ensuring the stability and integrity of many types of pitched roofs.