Lesson Notes By Weeks and Term v4 - SHS 3
≈SUBSTRUCTURE AND SUPERSTRUCTURE
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≈SUBSTRUCTURE AND SUPERSTRUCTURE
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Applied Technology
Class: SHS 3
Term: 1st Term
Week: 20
Grade code: 3.3.2.LI.6
Strand code: 3
Sub-strand code: 3
Content standard code: 3.3.2.CS.2
Indicator code: 3.3.2.LI.6
Theme: BUILDING CONSTRUCTION TECHNOLOGY
Subtheme: ≈SUBSTRUCTURE AND SUPERSTRUCTURE
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This lesson focuses on the final touches that make a building both beautiful and durable – the finishes. We see buildings every day in our communities, from our homes and schools to shops and offices. What makes some look new and well-cared-for, while others look old and neglected? Often, the answer lies in the quality of the finishes applied to key parts of the building. We will explore the specific finishes for the fascia board (at the edge of the roof), the railings (on stairs and balconies), and the plinth (the base of the wall).
This section covers the core content needed to understand building finishes for fascias, railings, and plinths. A. Definition of Key Terms Building Finishes: These are the materials applied to the external and internal surfaces of a building as the final stage of construction. Their purpose is threefold: Protection: To shield the structural materials from weather (rain, sun), chemical attack, and physical wear and tear. Aesthetics: To provide a decorative, visually pleasing appearance. Hygiene & Maintenance: To create smooth, easy-to-clean surfaces. Fascia Board: This is the long, straight board that runs along the lower edge of the roof, fixed directly to the roof trusses. In Ghana, you often see it where the gutters are attached. Function: It protects the wooden roof structure from rain, covers the ends of the roof rafters, and provides a solid base for attaching rainwater gutters. Railing (or Balustrade): This is a protective barrier installed along the edge of a staircase, balcony, veranda, or bridge. Function: Its primary purpose is safety, to prevent people from falling. It also provides support for people using stairs and can be a major decorative element. Plinth: This is the projecting base of an external wall, located just above the ground level. It is often slightly thicker than the main wall. Function: It protects the base of the building from "rain splash" (mud and water splashing up from the ground), physical damage from mowing or foot traffic, and moisture rising from the ground. It also creates a clean visual transition from the ground to the wall. B. Finishes for Specific Building Components
Here, we discuss the common materials used for each component and the appropriate finishes. Finishes for Fascia Boards Common Materials: Timber (e.g., Wawa, Odum), PVC (Polyvinyl Chloride). Recommended Finishes: Oil-Based (Gloss) Paint: This is the most common and effective finish for wooden fascia boards in Ghana. Why? It creates a hard, waterproof, and durable layer that provides excellent protection against the heavy rains and intense sun typical of our climate. Application Process: Preparation: The wood surface must be clean, dry, and smooth. Use sandpaper to smooth it and a cloth to remove dust. Priming: Apply one coat of wood primer. This seals the wood, prevents the paint from soaking in too much, and helps the topcoat stick better. Undercoating: Apply one or two coats of undercoat. This builds up the colour and creates a smooth base for the final coat. Allow each coat to dry completely. Topcoat: Apply one or two coats of the final gloss paint. Tools: Sandpaper, paint brushes, paint scrapers (for old paint), putty (for filling holes). Varnish or Stain: This is used when the homeowner wants to show the natural beauty and grain of the wood. Why? Varnish provides a protective, transparent layer, while a stain adds colour but still allows the wood grain to be visible. Considerations: Varnish may not be as durable as oil paint under direct, harsh sunlight and may require more frequent re-application. It is best for high-quality, attractive woods like Odum. PVC Fascias: These are modern alternatives that come pre-finished (usually in white). They require no painting. Their "finish" is simply their manufactured surface. Maintenance involves washing with soap and water. Finishes for Railings Common Materials: Mild Steel, Wrought Iron, Timber, Concrete. Recommended Finishes: For Metal Railings (Mild Steel): Anti-Rust Primer and Metal Paint: This is a crucial two-part process. Preparation: The metal must be free of rust, grease, and dirt. Use a wire brush and sandpaper to remove all traces of rust. Priming: Apply at least one coat of anti-rust primer (e.g., Red Oxide). This is the most important step. The primer chemically bonds to the metal and prevents oxygen and water from causing rust. Topcoat: Once the primer is dry, apply two coats of oil-based metal paint or gloss paint in the desired colour. This provides the final aesthetic look and an additional layer of protection. Tools: Wire brush, sandpaper, paint brushes, cleaning rags. For Wood Railings: The finishes are the same as for wooden fascia boards: Oil-based Paint for maximum protection and colour, or Varnish/Stain to showcase the natural wood. For interior railings, French polish can be used for a high-gloss, traditional finish. For Concrete Railings (Balustrades): Emulsion Paint: This is a water-based paint suitable for concrete and masonry surfaces. Why? It is breathable (allows trapped moisture to escape), easy to apply, and available in many colours. It is suitable for the vertical surfaces of the balusters. Textured Coatings (e.g., Grafiato): These are cement-based finishes that create a rough, decorative texture. They are very durable and good at hiding minor imperfections in the concrete work. Finishes for Plinths Common Material: Concrete blockwork with a cement-sand render. Recommended Finishes: Cement-Based or Weather-Shield Paint: These are specialized paints designed for exterior masonry. Why? The plinth is constantly exposed to moisture from the ground. These paints are formulated to be waterproof, durable, and resistant to algae and fungus growth. They are tougher than standard emulsion paint. Application: Applied with a brush or roller onto a clean, dry rendered surface. Tyrolean Finish: This is a very popular, durable, and cost-effective finish for plinths in Ghana. What is it? It is a mixture of cement, sand, and sometimes colour pigment, mixed into a slurry and applied using a hand-cranked machine called a Tyrolean flicker machine. It creates a rough, spiky, decorative texture. Why? It is extremely hard-wearing, weather-resistant, and its rough texture is excellent at hiding surface imperfections and dirt. Tile or Stone Cladding: This involves fixing ceramic tiles, porcelain tiles, or thin slabs of natural stone onto the plinth using a strong cement-based adhesive (tile cement). Why? This is the most durable and often most expensive option. It provides excellent protection against physical impact and water, is very easy to wash, and offers a high-end aesthetic look. Guided Practice (With Solutions)
Instructions: In your groups, discuss the following scenarios and propose a solution. Be ready to explain your reasoning to the class.
Question 1: A new community clinic has been built in a rainy area like Axim. The contractor used Wawa wood for the fascia boards. As the project consultant, what finishing material would you strongly recommend, and what are the three main steps to apply it correctly? Solution: Recommended Finish: Oil-based gloss paint. Reasoning: Wawa is a soft wood and Axim is in a high-rainfall zone. Therefore, the fascia needs maximum protection from moisture to prevent rot. Oil-based paint creates a non-porous, waterproof barrier that is more effective and longer-lasting in this environment than a varnish. Three Main Steps: Surface Preparation: Sand the Wawa wood smooth to ensure the paint adheres well and has a good finish. Priming: Apply one coat of wood primer to seal the wood. Painting: Apply at least two topcoats of oil-based gloss paint, allowing the first coat to dry completely before applying the second.