Purlin
Sheet under review by our engineersPurlins are horizontal beams that are part of the roof frame. They are laid parallel to each other, and it is directly onto them that the roof covering (your sheets, for example) is fixed. They transfer the weight of the roof to the main elements of the roof frame.
Why it matters for your home
If the purlins aren't strong enough or are too far apart, your roof sheets can sag between them, create water pockets, or even fly off in strong winds. Well-sized and spaced purlins ensure the rigidity and longevity of your roofing.
The African context
Often made of wood, the quality of purlins is essential. Untreated or poor-quality wood can rot or be attacked by termites. Excessive spacing between purlins is a common mistake made to save money, but it weakens the entire roof and can cause the sheeting to undulate or deform.
Red flags
- ⚠ The contractor suggests very small or visibly weak wooden purlins.
- ⚠ The spacing between purlins is very wide (more than 1.20 meters for standard sheets).
- ⚠ The purlin wood is green, undried, or untreated.
- ⚠ The purlins are not securely fastened to the main framework.
Questions to ask
- 1. "What is the planned spacing between the purlins?"
- 2. "What is the cross-section (size) of the purlins used and their quality (wood species, treatment)?"
- 3. "How will the purlins be attached to other elements of the roof structure?"
Cost hint (indicative)
The cost of purlins is included in the overall roof framing quote, but their quantity and quality directly impact the budget.
Related terms
At this stage of your project?
An independent DiasporaBuild inspector can verify on site before you pay.