One of the key steps in building a house is estimating the materials you will need. This information is essential for effective budgeting and a smooth construction process for anyone intending to build a three-bedroom house in Ghana, as it helps determine the number of blocks needed. In this comprehensive guide, we’ll walk you through everything you need to know, including formulas and tips for calculating the number of blocks in your project.
| Location | Price Range (GH₵) |
|---|---|
| Accra Metropolitan (Spintex) | GH₵ 2,100,000 for a furnished house |
| Kasoa (Dominase Estate) | GH₵ 250,000 for an uncompleted building |
| Kumasi Metropolitan (Diamond City Estate) | GH₵ 250,000 for an uncompleted house |
| Tema Metropolitan (Miotso Prampram) | GH₵ 6,200,000 for a completed house |
The process of building a house is exciting but challenging. How many blocks are needed for a 3-bedroom house? This question is critical because blocks are the building material, and their quantity directly determines the budget and deadlines.
Block Quantity Increments and Other Factors
Factors That Influence Block Requirements: The Variables Explained
A three bedroom house requires varying amount of blocks and the reasons are; Let’s dive into these in detail.
Wall Area and Height
The larger the house, the more blocks you will need. The wall space is based on the perimeter of the house (the building) times the wall height. For example:
- The part of a house with a larger building area (e.g., 12m x 10m) must have walls more extended than a smaller house (e.g., 8m x 6m).
- Higher walls (i.e. 3m instead of 2.7m) require many more blocks too.
Block Size and Type
The number of blocks needed varies with both the type of block and the size. The commonly used sizes of blocks in Ghana are:
- 400mm x 200mm x 150mm commercially available blocks
- 400mm x 200mm x 100mm (thinner, lesser blocks)
Because smaller blocks occupy less area, more blocks will be needed. Hollow blocks, for example, are usually lighter, easier to manage, and used in different instances than regular solid blocks.
Design Features and Openings
The total wall area is also cut down by the presence of doors, windows and ventilation space. For example:
- A house with a lot of windows or doors will need a few less blocks.
- An ornate design, rounded walls or certain architectural details may increase the number of blocks as well.
Wastage Considerations
Some of the blocks may be broken or cut during construction to fit into certain areas. You can consider having an extra 5-20% of blocks depending on wastage. For instance:
- E.g.: If your calculation indicates that you will need 2,000 blocks (add 10% more means that you should then buy 2,200 blocks).
- [Tip] When making estimates always err on the side of caution and find the next several blocks or larger number.
Block Requirements Calculation
A Practical Guide on How to Calculate the Required Number of Blocks
Now that we have all the ingredients, let’s proceed to the calculation. Here’s the process to calculate how many blocks you require if building a 3-bedroom house.
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Step 1: Measure Your Perimeter and Wall Height
- Calculate the perimeter of your house at first. For example:
- For example, if the size of your house is 10m x 8m, the perimeter is:
- Perimeter = (2 x Length) + (2 x Width) Perimeter = (2 x 10) + (2 x 8) = 36m
Next, measure your wall height. For the purposes of this example, let’s consider 3m.
| Category | Details |
|---|---|
| Specifications | – Carpet Area: 900–1100 sq ft (average 1000 sq ft)5 |
| – Rooms: 3 bedrooms, 2 halls/balconies, 1 kitchen, 2 toilets, dining/living room5 | |
| – Wall Area: Approx. 3000–3500 sq ft5 | |
| Block Requirements | – Average blocks needed: 3100–4000 blocks depending on design and wall height5 |
| – Factors affecting quantity: wall thickness, block type (hollow/solid), wastage allowance | |
| History | – Modern construction uses concrete blocks for durability, fire resistance, and affordability |
| – Traditional methods used red bricks before concrete blocks became popular | |
| Address | – Varies by location; urban areas may have higher costs due to labor and material prices |
| Worth/Price | – Estimated cost: $40,000–$80,000 depending on location and materials used |
Calculating Wall Area
- Total wall area = Perimeter × Wall height:
- Wall Area = Perimeter x Wall Height Wall Area = 36 x 3 = 108 m²
Adjusting for Openings
- Take the total wall area subtracted by the area of doors and windows. For instance:
- Let’s say you have 2 doors (2m² each) and 4 windows (1.5m² each).
- Total opening area = (2 × 2) + (4 × 1.5) = 10 m².
Adjusted wall area:
Adjusted wall area = Total wall area−Opening area= Adjusted Wall Area = 108 m² −10 m² = 98 m²
Determining Blocks Required
The number of blocks required (calculated in table) is simply the adjusted wall area divided by the face area of one block. For a basic block size of 400 mm x 200 mm (0.4 m x 0.2 m):
- The face area of one block = 0.4m x 0.2m = 0.08 m²
- Number of blocks required:
- Blocks Needed = Adjusted Surface of Wall / Area of For Basic Block Blocks Needed = 98 m²/0.08 m² = 1,225 blocks
Adding Wastage
Add 10% for wastage:
- Total Block= s Blocks Needed * 1.10 Total Blocks = 1,225 * 1.10 = 1,348 blocks
- Approximately 1350 blocks for a house 10m x 8m with 3 bedrooms and walls of 3m height. Final Estimate:
Block Types and Their Impact
Example — Right block type to affect the quantity
Different types of blocks will determine how many of them are needed, the total cost and the level of quality of the construction. Below are the major block types commonly used in Ghana:
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Concrete Blocks
- The standard size is 400 mm x 200 mm x 150 mm.
- General Purpose Construction: Used for residential and commercial buildings.
- Durable and cost-effective.
Interlocking Blocks
- Crafted to interlock like puzzle pieces minimizing mortar use.
- The accurate fitting can lower the wastage of blocks.
- Usually a bit larger which means less blocks typically.
Fly Ash Blocks
- A material made from industrial byproducts that is more sustainable.
- Is smaller, thus may needs more blocs
- Insulating and lightweight.
| Block Type | Advantages | Disadvantages |
| Concrete Blocks | Durable, widely available, cost-efficient | Heavy, requires more mortar |
| Interlocking Blocks | Reduces mortar use, faster construction | Higher initial cost |
| Fly Ash Blocks | Eco-friendly, lightweight | Less durable, higher quantity needed |
Case Studies and Examples
Example from Real Life: Block Requirements per Different 3-Bedroom House
- Small vs. Large Houses
- Small House (9m x 7m):
- Wall Height = 3m; Perimeter = 32m
- Calculation of Wall Area:Wall Area = 96m²; Adjusted Wall Area = 86m²
- Blocks Needed = Approx. 1,100 blocks (with wastage included).
- Large House (12m x 10m):
- P = 44m, H = 3m.
More blocks are needed for curved walls, multiple floors, or unique architectural features. Always consult a professional for custom designs.
Conclusion
There is to estimating block for a three bedroom houses in Ghana. Through wall area, block type, and wastage, you can decide your block cost and prevent spending more than you should.
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