Roofing Honor

Arts & Crafts

Requirements

1. Make a list of tools needed to work on roofs, listing the use and safety precautions of each tool.

   Answer: Tools and safety: hammer (nailing tiles — use with a firm handle); handsaw or circular saw (cutting wood — protective goggles); tape measure (measuring — no risks); plumb line and level (aligning — careful handling); square (right angles); extension ladder (accessing the roof — firm base, 75° angle). — The Ministry of Labor's NR-35 (Work at Heights) requires a fall-arrest harness and certified anchoring for any work above 2m — disregarding it is grounds for the work to be halted and a heavy fine for the technical manager.

2. What equipment is needed to make a roof with "trusses"? Describe how you would go about raising them into place.

   Answer: Equipment: pre-assembled trusses, hoisting ropes (15-20m), a winch or pulleys, scaffolding or a ladder, trestles, nails/screws for fixing, a plumb line and a safety harness. To raise: assemble each truss on the ground, fix two ropes to the upper ends, send one person up on the scaffolding/wall. — Trusses are triangular frameworks that support the roof — the rope-and-pulley system can reduce the weight by up to 4×, a physical principle used since antiquity in the construction of Egyptian and Greek temples.

3. Cite the main types of wood used in roofs in your region and their use in various types of roofs, such as: shed (single-slope), gable (two-slope), segmented, hip, colonial, etc.

   Answer: Common woods: peroba-rosa (durable, used in large structures), ipê (high durability, colonial roofs), treated eucalyptus (economical, shed and gable roofs), cumaru (replaces ipê), garapeira and angelim. — Autoclave-treated eucalyptus (CCA) revolutionized popular Brazilian construction in the 2000s — before, only peroba and ipê were used, but the pressurized treatment made eucalyptus durable (40+ years) at 70% lower cost.

4. Answer the following, regarding the preparation of the material:
   • How is the wood for roofs cut and how is the timber stored?
   • How is the wood used in roofs prepared?
   • How is a roof made with rafters? What materials and equipment are used in your region?

   Answer: 1) The cutting of wood for roofs is done with a circular saw or power saw, at the angles and measurements defined by the structure's design. Storage must be in a covered, dry and ventilated place, with the pieces stacked on battens (spacers) that create spacing between the layers, allowing air circulation and avoiding moisture, warping and fungal attack. 2) The preparation of the wood includes planing the faces to make them straight and regular, treatment against termites and rotting (immersion or brushing with CCA, creosote or linseed oil) and cutting to the final measurements, with the joints and angle cuts ready for assembly. 3) A roof with cabling (a truss/trestle structure) is made by mounting the wooden trusses on the walls, which support the purlins; on the purlins the rafters are laid and, on them, the battens, where the tiles are finally fixed. The materials and equipment common in the region are: hardwood or reforestation wood (rafters, battens, purlins, trusses), nails, screws and metal brackets, tiles (ceramic, fiber cement or metal), in addition to a circular saw, hammer, drill, level, plumb line, square and tape measure. — The steel cables used in roof tie rods follow the ABNT NBR 6122 standard — they must have a minimum strength of 1860 MPa and galvanized protection for outdoor use, preventing rust that would compromise the structure.

5. Answer the following, regarding thatched roofs:
   • Can a thatched roof be made in any design?
   • What is the most practical design for making a thatched roof?
   • Cite some advantages and disadvantages of a thatched roof.
   • What are the weather conditions that damage a thatched roof? How should protection be done?

   Answer: 1) No. A thatched roof cannot be made in just any model: it requires a steep slope to drain rainwater well. Models with a slight slope retain water and rot quickly; the ideal is a gable roof with a high slope (45° or more) or the conical model. 2) The most practical model is the gable roof with a steep slope, with the thatch fixed by tying (vine, wire or fiber) over the structure of poles/rafters, because it is simple to assemble and efficient at drainage. 3) Advantages: low cost, natural and renewable material, excellent thermal insulator (keeps the environment cool) and a pleasant rustic appearance. Disadvantages: shorter durability than other materials, high flammability (fire risk), the need for periodic maintenance and replacement, and it can harbor insects and small animals. 4) The weather conditions that most harm a thatched roof are rain (moisture that rots the thatch), strong sun (which dries out and breaks the fibers) and strong wind (which displaces or tears off the covering). Protection is achieved with a high slope for rapid water drainage, firm and well-distributed tying of the thatch, generous overlapping of the layers, periodic maintenance and replacement of the damaged parts and, when possible, treatment of the fibers to retard fire and rotting. — The Xingu Indians developed buriti palm thatched roofs that last up to 12 years with maintenance — the secret is in the slope greater than 60° that drains all the water without allowing infiltration into the lower layers.

6. Have practical knowledge in working with thatch and demonstrate the ability to make some bundles for roofing.

   Answer: To make roofing bundles: harvest dry thatch (sapé grass, buriti palm or donkey-tail grass); cut it to a uniform length (1.2-1.5m); separate it into bunches of approximately 30cm in diameter; tie each bunch in two positions (near the ends) with plant fibers (vine, sisal, coconut fiber); let it dry for another 2 days before applying it to the roof, overlapping the layers to ensure waterproofing. — The technique of overlapping in staggered layers is the key to waterproofing — each upper layer covers 70% of the lower one, a physical principle called the 'tile effect' also used in zinc and clay for the same hydrodynamic reasons.

7. Answer the following, regarding labor:
   • How many workers are needed to build a roof with gable-style trusses?
   • Describe how to begin work on the roofing in item A.
   • Say and, if possible, demonstrate how you would do:

   Answer: 1) For a gable roof with trusses, an average of 4 to 6 workers are needed: 1 master/carpenter in charge, 2 carpenters to assemble and adjust the trusses and purlins, and 1 to 3 helpers for transport, hoisting the pieces and fixing. 2) To start work on the roof, first ensure that the walls and gable ends are finished, leveled and cured, and check the squareness and level of the upper plane (the base where the trusses will rest). Then mark the position of each truss, raise and fix the first truss plumbed and braced, then the others in the same alignment and spacing; on them the purlins, rafters and battens are laid, leaving the structure ready to receive the tiles. 3) Demonstrate in practice how you would carry out the assembly of the roof covering: the positioning and fixing of the trusses, the laying of the purlins, rafters and battens and the placement of the tiles, checking plumb, level and alignment throughout the process. — The rule 'start at the ends' comes from centuries-old carpentry practice — the trusses at the ends act as 'guides' ensuring the perfect parallelism of all the others, avoiding twisting of the structure along the ridge.