Designing and Building in Central and East Africa

If You Plan to Build 100 Schools in Congo

.                within a limited time, you have to be efficient.

This means one needs a standard design prepared with an even more standardized system that allows small adjustments to be made for each project.

Having broken ground on more than 100 schools over the last year, my strategy for creating project construction documents has evolved.  In the beginning, I created all of the standard drawings for classrooms (in blocks of 3, 4, 5, and 6) and latrines.  Below you can see an example set for a block of three classrooms.  The brick + cast in place concrete + corrugated roof panel scheme is typical of rural East African architecture.  All dimensions conform to the Congolese Ministry of Education standards (which sometimes differ between provinces) and provide seating for approximately 30 students per classroom.

In the beginning, I would adjust each drawing set to cater the communities’ needs.  Some would want water catchment; some a ceiling, or a different type of flooring.  My first few sets of documents were consumed in these details – as I represented each variation visually.  It became clear by my 15th school however, that the number of projects and their pressing deadlines would not permit such attention to detail.  I have therefore begun using this single set of drawings and directing the contractor to the budget.  This allows us the control all construction details through contractual language and the material quantities that arrive on site.

Below is a Bill Of Quantities that we use to build the most common school unit of 3 classrooms, 2 latrines and a water capture system.  In this variation, the foundations have been budgeted as stone masonry which frames the cheapest flooring option: compacted soil topped with a brick pavers and a pure cement finish.  Quantities for bricks, sand and gravel vary according to material quality and brick dimensions – and have been slightly increased to ensure sufficient quantities.  (It should also be noted that all local materials here can be decreased in the event that the community has access to such materials and can contribute them to the building effort.)  Tools and measuring instruments should also be factored into project costs, as their quality usually limits them to a “one project” life span.  In all, a project of this scope (in the accessible regions of South Kivu) will cost less than $22,800 and take about 3 months to build.

Material Unit Quantity
1 Sand m3 46
2 Gravel m3 9
3 Masonry Stones m3 21
4 Bricks pce 40000
5 Scaffolding Posts (± 5m each) pce 60
6 Scaffolding Boards pce 6
7 Ciment sac 230
8 Ventilation Blocks pce 108
9 Formwork Wood (3.5m ea.) pce 35
10 “2×4″ Wood  (3.5m ea.) pce 94
11 “2×2″ wood perlins (3.5m ea.) pce 75
12 Fascia Board 25cm wide, 3.75m long pce 18
13 Shovel pce 5
14 Pick pce 3
15 Hoe pce 2
16 Machette pce 1
17 Trowel pce 2
18 Spirit Level pce 1
19 Wheel Barrow pce 2
20 Digging Bar pce 1
21 Measuring Tape, 50m pce 1
22 Measuring Tape, 5m pce 1
23 Mason Hammer, 5 kg pce 2
24 Mason Hammer, 1 kg pce 1
25 Mason Bucket pce 4
26 Wheel Barrow pce 1
27 Carpenter Hammer pce 2
28 Mason Square pce 1
29 Crow Bar pce 1
30 Hacksaw pce 1
31 Hacksaw blade pce 10
32 Scissors (Tin Shears) pce 1
33 Large Tarp pce 2
34 Paint Roller pce 6
35 Brush, 3″ pce 4
36 Brush, 4″ pce 6
37 Sand Paper ml 2
38 20 Liter Bucket pce 6
39 Large Sand Sieve (5mm) m2 1
40 Fine Sand Sieve (2mm) m2 1
41 Deisel Fuel litre 10
42 12mm String (100m Roll) pce 1
43 Nylon String  (100m Roll) pce 2
44 Rebar HA6 (12m ea.) pce 52
45 Rebar HA8 (12m ea.) pce 42
46 Galvanized Tie Wire kg 15
47 Galvanized Roof Panel (G30) pce 103
48 Galvanized Roof Crown pce 15
49 Roofing Nails kg 15
50 15mm Nails kg 10
51 12mm Nails kg 18
52 10mm Nails kg 10
53 8mm Nails kg 10
54 5mm Nails kg 6
55 PVC Gutter ml 44
56 Gutter Ends pce 4
57 Gutter/PVC connection pce 2
58 Gutter Brackets pce 26
59 PVC 110mm ml 15
60 PVC 110mm Elbow pce 3
61 PVC 110mm “T” pce 3
62 PVC Glue tube 2
63 Plastic Water Tank (2m3) pce 1
64 1/2″ Tap pce 1
65 Complete Wood Door 0.8×2.10 pce 2
66 Complete Wood Door 0.9×2.10 pce 3
67 Complete Wood Window (150×110) pce 6
68 Complete Wood Window (200×110) pce 6
69 Chalk / Lime (50 kg) sac 3
70 Latex Paint litre 45
71 Oil Paint litre 26
72 Chalkboard Paint litre 3
73 Kitchen Salt kg 6
74 Student Desk pce 45
75 Teacher Desk pce 1
76 Teacher Chair pce 1

I provide these details not to help you understand what a good three room school building will cost – or how to build such a building.  There are numerous beneficial details that are missing from this example. Rather, I present it here to show what a team of locally trained masons could be expecting to build.  It could also be assumed that a rural community would enjoy seeing such an example built for their school.

I welcome you to use this information as a reference point for your own designs.  Any improvements to this scheme could drive the project cost up – but in my view, any and all considerations taken towards appropriate, contextual design can have lasting positive affects towards the sustained development of your community.

The next step, of course, is the how.  Material procurement, appropriate construction methods, conflict, and corruption present the most formidable challenges to project completion.  … But perhaps that will be left to a follow up post…

Happy building!

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6 responses

  1. busharchitect

    Interesting but a few questions (hope you don’t mind!): 1) why the concrete columns? They cannot be structural as they are too far apart and in fact they will probably weaken the structure as the adjoining brick walls will not be tied into them and they will therefore weaken the corners and cross-wall junctions of the buildings. Why not leave them out and replace if necessary with brick piers. This will save money and improve construction. 2) Similarly with the top ring beam; is this necessary. I cannot make out how many roof trusses there are but assume 2 per classroom with cross and end walls taken up to carry the purlins? 3) There seems to be a large longitudinal beam made up of cross members running down the centre of the building; is this necessary? Are there large wind loads?
    I have been trying for many years to omit concrete beams and columns in simple single-storey rural buildings as they simply drive up costs without improving or strengthening buildings. In fact they usually weaken the buildings (see comments above and also take into account the fact that the concrete is usually poorly mixed of sub-standard materials with too much water!). Given the fact that most rural buildings receive little or no proper supervision then the secret is to make them as simple as possible. These are lessons that I have learned from many years experience…………………………..which has often been very frustrating!

    June 9, 2013 at 8:10 pm

    • BushArchitect – Thanks for the comments and questions. Don’t mind at all!

      1) I agree with you that the first thing that could be cut form this design would be the columns at the corners. In the initial (and only) design meetings I had proposed two additional embedded columns along the facades of each classroom. These were eventually eliminated due to budget constraints. The corner columns do however provide some structural stability. Assuming quality bricks and a uniform running bond, the brick walls interlock with the cast-in-place concrete. That being said, brick piers/pilasters/butresses would be the best alternative and would save on cost.
      2) To clarify, each wall is joined together by a continuous reinforced concrete ring beam. This unifies the structure and provides a system to distribute the point load of each truss down through to the masonry. This design shows 3 trusses per class – keeping the distance between each truss (or end wall) to less than 2.5 meters. This distance could be greater, but I would then recommend increasing the dimensions of the purlins. Fundis often have to sit on them during roof installation.
      3) The longitudinal beam that you are referring to seems to be the reinforcing that I show between each truss. These are typically of the same dimension wood as the purlins and prevent lateral racking between the trusses. I have shown these “X”s in each bay – though one per classroom should suffice.

      This design is used in numerous regions throughout South Kivu. We have occasional wind loads along the Lake and on top of hills, but very little wind on sites surrounded by dense forest. How I would love to design a different building for each community… but 100 schools is such a deadline, that… unfortunately, one size has to fit all.

      I think your desire to minimize the use of concrete has some merits. Mixtures are often shorted and almost always mixed on the ground. This misuse can create more problems than benefits. Proper construction oversight is essential not only to prevent these errors, but also to teach young builders the best practices of our profession.

      June 14, 2013 at 3:36 pm

  2. Carlos

    Nice, standardized blueprints help a lot in these situations. Wish you the best of luck in the construction phase.

    June 10, 2013 at 12:00 am

  3. I always enjoy your posts. Interesting, informative and very revealing about your day to day work. Noble work at that. Keep it up Charles.

    June 10, 2013 at 10:11 pm

    • Thanks for stopping by, David! Looking forward to posting more as I get the time :)

      June 14, 2013 at 3:40 pm

  4. Thanks for sharing. Utilizing the appropriate construction methods when building from the ground up is a challenge to say the least, and being able to gain insight through pointed breakdowns of the necessary building supplies, materials, water systems, etc. is a great way to form an understanding.

    October 7, 2014 at 9:39 pm

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