Cover Image
close this book Self - Help construction of 1-story buildings
View the document About this manual
close this folder Introduction
View the document A note on the development process and construction
View the document How to use this manual
View the document What this manual will talk about
close this folder Basic planning and design
close this folder Site and position
View the document How big should the site be?
View the document How accessible, and how private should the site be?
View the document What kind of soil should the site be on?
View the document How well is the site drained?
View the document How should the building be placed on its site?
View the document Summary of factors affecting site selection
close this folder Size, shape, and floor plan
View the document Schools
View the document Health clinics
close this folder Homes
View the document What size will each room be?
View the document Using measuring units to help the family plan its own room sizes
View the document Helping the family draw its own floor plan
View the document Drawing the floor plan of a house
close this folder Doors, windows, and ceilings in all buildings
View the document Where will inside doors be placed?
View the document How high will the ceiling be?
View the document Where will windows and outside doors be placed? how will they be designed, and what size will they be?
View the document Windows in a tropical climate
View the document Protecting the inside of the building from rain and insects
View the document Take advantage of any breeze
View the document Windows in a desert-like climate
View the document Exterior doors
close this folder Construction materials
View the document Rammed earth (mud, pise) and adobe blocks
View the document Wood
View the document Bamboo
View the document Stone and rock
View the document Cement and materials made with cement
View the document Mortars
View the document Concrete
View the document Reinforced concrete
View the document Blocks
View the document Concrete blocks
View the document Sand - cement blocks (sandcrete)
View the document Stabilized earth blocks
View the document Summary
close this folder Detailed planning for construction
close this folder Planning foundations
View the document Footings
View the document Foundation walls
View the document Deciding upon the materials and dimensions for foundations
View the document Drawing final foundation plane
close this folder Planning floors
View the document Types of floors
close this folder Planning walls, windows, and doors
View the document Wall height and length
View the document Wall thickness
View the document Placement of doors and windows
View the document Construction details for doors, windows, and interior walls
close this folder Planning roofs
View the document Roof styles and their functions
View the document Roof materials
View the document Construction details for roofs
close this folder Directions for construction
close this folder Setting out (laying out)
View the document Orientation
View the document Marking the foundation outline
View the document Batter boards
close this folder Construction of foundation footings
View the document Digging the foundation trench
View the document Formwork for Footings
View the document Making the concrete for foundation footings
View the document Pouring concrete for foundation footings
View the document Curing concrete footings
View the document Reinforced footings
close this folder Construction of the foundation walls
View the document Concrete foundation walls
close this folder Block foundation walls
View the document Making blocks
View the document Laying block foundations
View the document Finishing the mortar
View the document Rock foundation walls
close this folder Construction of floors
View the document Earth floors
View the document Concrete floors
close this folder Construction of walls, windows, and doors
close this folder Block and brick walls
View the document Making the blocks or bricks
View the document Laying blocks and bricks
View the document Framing windows and doors
View the document Roof preparation
close this folder Rammed earth walls
View the document Earth mixture
View the document Forms
View the document Procedure
View the document Framing windows and doors
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close this folder Construction of roofs
View the document Flat roofs
View the document Shed roofs
View the document Gable roofs
close this folder Construction with bamboo
View the document Bamboo for foundations
View the document Bamboo for frames
View the document Bamboo for floors
View the document Bamboo for walls
View the document Bamboo for doors and windows
View the document Bamboo for roofs
View the document Bamboo reinforcement of concrete
View the document Preservation of bamboo
close this folder Latrines
View the document Location of latrines
View the document Pit
View the document Base
View the document Floor
View the document Shelter
close this folder Construction in earthquake areas
View the document Selection and preparation of the site
View the document Selection of building materials
View the document Reinforcement of buildings
close this folder Appendices
View the document Calculations to check whether a proposed site will support a building
View the document Step-by-step directions for drawing foundation plans
View the document Estimating the amount of concrete needed for a floor
View the document Estimating materials needed to build walls
View the document Reference tables for concrete construction
View the document Metric measurements used in this manual and their U.S. equivalents
View the document Sources of further information
View the document ''Human measuring pieces'' for designing room size and floor plan

Foundation walls

The foundation walls can be made of rock, or they can be made of blocks of concrete, sand-cement, or stabilized earth.

All of these materials are strong enough to support the walls and roof of most 1-story buildings. The choice depends on what materials are available, the builders' budget, and whether or not earthquakes or severe weather conditions will require reinforcement in the foundation.


Foundation walls

 

Rock Foundation Walls. A rock foundation wall is built by setting stones that are 20 to 40 cm. long in mortar. The rocks must be cleaned so that no rocks remain on them. All the spaces between the rocks must be filled with mortar (these spaces are called "joints"). In addition, and most important, they must be laid so they overlap. If a straight line can be drawn between the rocks from the top to the bottom of the wall, a crack will develop.

Rock foundations are the least expensive to build. However, they require a large number of rocks, and it is difficult to clean, level, and overlap the rocks properly.

If the building position is on rocky ground, or on dry, well-packed clay soil, the footing for a rock foundation wall should be 4 to 8 cm. thick.

In less stable soils, such as sand, or gravel, the footing should be at least 10 cm. thick. In soft black soil, drained marshland, and made earth, the footing should be reinforced and should be 10 cm. thick.

In rocky or hard-packed clay soil, rock foundation walls need only be 30 cm. deep. In other soils, they should be at least 45 cm. deep.

Rock foundation walls should be at least 30 cm. thick, and they will be much more stable if they are flared at the base to 45 cm.

Block Foundation Walls. Whether built of concrete, sand-cement, or stabilized earth, block foundation walls are made by laying level rows of blocks on concrete footings until the wall reaches the planned height of the floor. Each row of blocks, called a course, is joined by mortar, as are the ends of each block.

Block foundations cost more to build than rock foundation walls (except in areas where the rock must be transported over large distances), but block foundation walls can be put up faster, and they are easier to build well.


Block foundation walls

 

In rock or firm clay soil, a block foundation should be 45 to 60 cm. deep. In less stable soil, a block foundation should NOT be used.

The width and thickness of the footing depend on the size of the blocks being used. In general:

• the footing should be as thick as the blocks are wide;

• the footing should be 3 times as wide as the blocks.


The footing should be 3 times as wide as the blocks.

 

Frost Line. The frost line is the depth to which the ground in any area freezes in the winter. In climates with freezing temperatures, the footing must be entirely below the frost line.

The table below gives suggested depths to be safely below the frost line in different climates:


Frost line

Lowest Temperature in Winter, Degrees Celsius

Safe Minimum Depth for Top of Footing

-1

45cm.

-5

75cm.

-11

90cm.

-18

1.05m.

-22

1.20m.

-28

1.30m.

Sloping Ground. If a building is built at an angle on a slope, it will tend to slide downhill, causing the foundation and walls to slip and/or crack. Thus if the ground under a building slopes or is uneven, the trenches for the foundation footing must be completely levelled.


Sloping ground

 

If the ground slopes sharply, it may be easier, or necessary, to "step" the trenches. When block foundation walls are planned, it's important to make each step the height of one or two courses of blocks.


Important to make each step the height of one or two courses of blocks