Purlins are beginning to be replaced with what?

Purlins are beginning to be replaced with what?

• A. Large wooden "I" Beams
• B. Open Web Trusses
• C. Beams are becoming the only safe structural element to walk on and ladder against
• D. Steel girders

Answer: (B)

Open web trusses are replacing purlins because they provide long spans with much less weight, making roof systems lighter and easier to install. Their open-web design also leaves clear spaces for running electrical, plumbing, and HVAC lines, and it allows quicker access for maintenance and ventilation work. This combination of strength, efficiency, and serviceability is why modern roofs commonly use open web trusses rather than traditional purlins. Large wooden I-beams and steel girders aren’t the standard replacement for purlins in typical roof framing, and the idea that beams are the only safe surface to walk on isn’t accurate or a real construction practice.

Open web trusses are replacing purlins because they provide long spans with much less weight, making roof systems lighter and easier to install. Their open-web design also leaves clear spaces for running electrical, plumbing, and HVAC lines, and it allows quicker access for maintenance and ventilation work. This combination of strength, efficiency, and serviceability is why modern roofs commonly use open web trusses rather than traditional purlins.

Large wooden I-beams and steel girders aren’t the standard replacement for purlins in typical roof framing, and the idea that beams are the only safe surface to walk on isn’t accurate or a real construction practice.