| Handbook for building homes of earth |
The home builder needs a good place to build. The lot should be big enough not only for the house but also for a yard and a garden. Plenty of suitable soil must be available either on the property or nearby. Other factors are important, too:
The lot has to have good drainage. Standing water or muddy ground can be very destructive to earth houses. If water stands on the area after heavy rains, the lot will not be satisfactory unless trenches or ditches can be dug to carry the water away rapidly. Figure 19a shows a good site and Figure 19b a bad one.
The location of the home should also be convenient to roads, markets, or the owner's job.
Usually, old home sites work out well because the soil has stabilized itself or settled under the weight of the old house.
LEVELING -THE LOT - Clear (he site of unwanted brush anti vegetation before beginning construction. All vegetation and the organic top soil should be removed from the area the house will occupy. All spongy or soft material should be removed down to good, firm soil. Leave enough extra space outside the limits of the house for a working area. Save plants which will have ornamental value after the home is built.
After the location of the house is marked on the ground, mark the outlines of the house with stringlines nailed on stakes. Then level the ground inside the stringlines. This is shown in Figure 20. Low areas may be filled in from adjacent high areas, provided good soil, which will not wash away. is used. Any fill material placed inside of the string lines should be well pounded with a hand tamper to make a solid foundation. Otherwise, settlement of the fill material could cause cracks in the house. Extra dirt from the leveling job is kept for later use if it is the kind suitable for building.
FINDING THE GROUND LEVEL - Before laying out the actual outlines of the house, the general area it will occupy should be fairly well graded or leveled anti an accurate floor level should be marked out carefully.
This is done easiest by driving stakes into the ground. First, drive a stake to the desired floor level. Protect it by surrounding it with other stakes. Then, drive in other stakes around the approximate outlines of the house to exactly the same floor level. This can be done in two ways.
To find the correct height of the additional stakes, if possible, a surveyor's level should be used and the tops of all the stakes can be accurately sighted. (For convenience, if the surveyor's level is used, make the tops of the stakes somewhat higher than floor level and later measure down from each stake to the desired floor level.)
If a surveyor's level is not available, an ordinary clear or translucent plastic water hose will work just as well. Fill all but about a foot of the hose with water.
By adjusting the water level at one end of the hose to the exact floor level indicated by the first guide stake, then all of the other stakes may be driven to the proper level by matching the tops of those stakes with the water level at the other end of the hose. The water hose method is shown in Figure 21.
By driving the first stake into the ground at what you judge to be the highest point of your lot, all of the other stakes, then, will stick out of the ground a little higher. If it turns out that the guide stake is lower than the ground level at other stake points, drive another stake next to the guide stake leaving enough length above the ground for later measurements. For example, have this added stake exactly one foot higher than the guide stake. Then drive the other stakes to match it. The desired level can be determined by measuring one foot down from the tops of these stakes or to such level as to have the lowest corner above grade.
The water hose also can be useful at other times during construction. It can be used as an accurate means of finding other levels or elevations. It is useful in finding the correct height of footings and foundation walls, checking to see that blocks are being laid level or even checking the top layer of blocks before the roof is placed.
It is a good idea to have corks or plugs to stop up the ends of the hose to keep the water from running out when the hose is not being used.
LAYOUT OF THE CONSTRUCTION - The next step is to mark the exact location of the exterior walls on the ground.
The proper dimensions and shape are included in the house plans. Keep in mind which way you want your home to face. An architect can be very helpful. Consider such things as prevailing breezes, direction of sun, appearance, distance from street and property lines, etc.
After the location has been selected, the next step is to erect batter boards. These boards, Figure 22, should be at least 5 feet long so that adjustments can be made after they are placed in the ground. A set of batter boards should be placed at each corner of the exterior walls of the house. The batter board' at the corner where the ground is the highest should be set about 18 inches above the ground. Those at the other corners should be set at the same level (in other words they will be higher above the ground). They must be sturdy enough to hold the tight string lines which will be stretched from them to define the walls of the house.
Square corners can be made and checked simply.
To make a square, take three boards, exactly 3, 4 and 5 units long and nail the end. together as shown in Figure 23a.
The angle between the 3-unit and the 4-unit boards will be 90 degrees or a "square" angle. By aligning the strings along these two boards as in Figure 23b, two sides of the hose can be properly positioned.
To begin the layout of the house, a stake should be driven about three feet inside one set of batter boards to form the first exterior corner. The right angle of the square is then located properly at this stake and all measurements begin from here. The stake would be placed just below where the strings cross in Figure 23b.
String lines are then stretched between batter boards to mark the direction and length of sides of the walls. This procedure of measuring and laying out square corners is continued around the outline of the house until the task has progressed back to the starting point.
If the house outline is in the shape of a square or a rectangle, the alignment can be checked by measuring the diagonals - the length between opposite corners. If the outline has been properly laid out, and the corner angles are square, the length of the two diagonals will be exactly the same. If these lengths are not equal, adjustments should be made until they are by moving the positions of the strings on the batter boards. These diagonals are shown as heavy lines in Figure 24.
Even when a square is not available, an accurate layout can be made. To do this, mark off two corners of the house at the proper distance apart to establish a side of the house in the desired direction. Then, as closely as you can estimate their positions, lay out with strings the two sides that lead from the first side you have established. These sides should be of proper length. When this has been done, check the diagonals. If they are not exactly equal, the last two corners should be moved until the diagonals match each other. This will assure an accurate square or rectangle.
It is best to use more than one set of string lines to mark the dimensions of the building. The first set of lines marks the location of the outside edge of the walls of the building. However, the limits of the excavation for the footings (which are discussed in the next chapter) and foundation wall will usually be outside of the location of the walls. In this case, additional string lines are placed on the outside of the first set to mark the limits of the hole to be dug.
Once the string lines for the excavation have been placed, the limits of the excavation should be properly marked on the ground so the workmen will dig along the proper lines. This can be done by driving guide stakes directly beneath the string lines marking the excavation, or by spreading a thin line of lime beneath the string lines. In either case, the string lines should be removed during the excavation so they will not be broken by the workmen. Be sure to mark the location of the string lines on the batter boards so they can be put back in exactly the same place after the excavation is complete.
DRAINAGE - If the house is to be built on nearly flat ground, d drainage of the lot away from the house should now be considered. Any lines of wash, or gullies that cross the construction site should be turned away by digging new ditches away from the house and filling in the ditches with tamped soil. It is also important that the ground level next to the building be higher than the rest of the lot so that water will drain away from the building. A canal or ditch several fee away from the foundation may be necessary to carry away excess water during heavy rainfall.