| Self - Help construction of 1-story buildings |
Two kinds of drawings are important aids to help the field worker and community members visualize their foundation plans and check their progress during construction:
• a cross-section view of the footing and foundation wall; and
• a view from above of the footing and foundation wall measurements.
When a community group is ready to begin construction of the foundation, it's a good idea to help them build a small demonstration section of footing and foundation wall that they can use along with these drawings to check their progress. The demonstration section will help everyone see what they have planned to do; at the same time, it will give them practice in the construction techniques and skills they must use on the actual foundation.
DRAWING A CROSS-SECTION VIEW OF THE FOUNDATION
Drawing a cross-section view of the foundation is simple. Here are examples of a cross-section for a rock foundation and for a block foundation wall. Both drawings show concrete footings as well:
DRAWING FOOTING AND FOUNDATION MEASUREMENTS (VIEW FROM ABOVE)
Drawing the foundation measurements as they would look from above is also simple.
Here are step-by-step instructions for drawing the foundation measurements of a sample building:
1. Draw a solid line representing the outside dimensions of the walls of the building, This line will also represent the outside dimensions of the foundation wall.
2. Draw a second solid line inside the first one to represent the inside dimensions of the building's walls. This line will also represent the inside dimensions of the foundation wall. The space between the two lines should be exactly the width of the planned walls to scale.
3. Subtract the width of the wall from the planned width of the foundation footing. Divide the remainder in two and convert the answer into the scale dimension being used in the drawing. This figure represents the distance between the inner side of the wall and the inner side of the foundation footing.
4. Draw a dotted line inside the drawing of the walls. This line represents the inner dimension of the footing. The space between it and the inside solid line (step #2) should be exactly the distance calculated in step #3.
5. Draw a dotted line outside the drawing of the walls. This line represents the outer dimension of the footing. The space between it and the outside solid line (step #1) should be exactly the distance calculated in step #3.
6. On either side of the drawing's length, add a solid line exactly as long as the longest wall (that is, the longest outer solid line).
7. On either side of the drawing's width, add a solid line exactly as long as the longest wall (that is, the longest outer solid line).
8. Place a mark along each line from steps #6-7 wherever the outer wall turns a corner. Indicate the actual length of each straight section of wall.
9. Outside the lines drawn in steps #6-7, draw two more solid lines exactly as long as the length and width of the outer dotted line. Mark these lines to indicate the actual length of each straight section of foundation footing.
10. Underneath the completed drawing, write down what the footing and foundation wall will be made of and their cross-section dimensions.
11. The completed drawing is an actual scale drawing showing the trenches that must be dug for the footing and the dimensions of the foundation walls.