Masonry & Concrete Construction

This book is a guide to methods, materials and techniques used by professional masonry and concrete contractors. Masonry is an ancient profession that in some ways has changed very little for centuries. But it's also a modern profession, with techniques and materials improving as science makes new discoveries. The emphasis throughout this new edition is on modern practices. But that doesn't mean the tried and true methods that really are still the best are neglected. 

I've written this manual to cover all phases of masonry and concrete construction. You'll find everything from on-site preplanning, through footings, foundations and walls. From fireplaces and chimneys to seismic reinforcement. From brick and limestone veneer construction to techniques for stain removal. There are in-depth discussions of the materials you'll use - the properties and characteristics of ingredients found in a batch of cement, for example. 

Throughout this revised edition, I've either expanded or updated every section. Often I've done both. And I've emphasized safety. There's an entire chapter devoted to the Occupational Safety & Health Act. In this section you'll find all the applicable OSHA sections pulled together into a handy condensed form. And finally, there's information that will help you make bid-winning estimates for all kinds of masonry and concrete construction. 

Of course, this book can't cover everything you might ever want to know about masonry and concrete. No single volume could. I wrote it for the busy, working masonry and concrete contractor who needs a handy reference to keep in the cab of his truck. When you're out on the job site and need to know a formula or how to deal with some problem, you've got the help you need close at hand. And back at the office, you're sure to use it as you're going over blueprints and writing estimates. 

Planning the Job

In this chapter, we'll cover what you need to know and do before you start working at the job site. Since you'll be involved at the very beginning of a building project, with the foundation, you have to make sure it's in the right place. The framers will simply build on the footing you laid. If you've built it partly on the neighbor's lot, or a few inches over the setback line, and it's not discovered until after the roof is finished, you're not going to like their choice of who to blame. 

Let's begin at the beginning - with the building code. 

Check the Building Code 

All residential and commercial construction must comply with local building codes and requirements. So your first step, before starting any project, is always to check the code. The local building inspector or city engineer should have copies of the current code available.

The first sections of the building code cover the general provisions and define the terms used in the code. The rest of the code covers space and structural requirements, fire safety and many other conditions and limitations. Building codes often spell out each and every detail. That makes it easy to work to the code once you know where to look.

Building codes vary in their details, but most use the same standard terms. Let's look at some of these definitions. Many of them are illustrated in Figure 1-1.

Building Line - A legal-determined boundary that no part of the building can cross. Exceptions are common, but the details vary widely. Never assume that what's allowed in your town is also OK in the next county. Always check the code before you start work.

Figure 1-1
Terms used in the building code

Distance Separation - This describes the amount of open space required between buildings. Open space helps keep fire from spreading from one structure to its neighbors.

Lot Line - A surveyed and recorded boundary that separates one piece of property from another. The same phrase also describes the legally determined boundary that separates a piece of private property from a public street or other public property.

Premise - A term used to describe collectively a piece of property as well as any buildings or structures on it.

Property Line -The legal boundaries marking a lot or parcel of property.

Setback - The open space required between a building line and the street centerline.

Street Line - A boundary separating a lot or parcel of land from the street. The street line and building line are the same if there's no setback required. 

Basement - A space in a building that meets both of the following requirements: First, it's partly below grade. Second, more than one-half of its height, measured floor to ceiling, is above the average outside grade. Most codes allow habitable space in a basement if the basement floor isn't more than 4 feet below the average outside grade. Most codes also treat a basement as a story if the floor directly above it is at least 7 feet above the finished grade. See Figure 1-2. 

Cellar - A space in a building that's similar to a basement, except for the following differences. First, the floor level is more than 4 feet below the level of the aver- age outside grade. Second, less than one-half a cellar's floor-to-ceiling height is above the average outside grade. Most codes don't allow habitable space in cellars, although a recreation room is usually allowed. Finally, cellars are rarely counted as a story. See Figure 1-3. 

Check the Site Deed 

There are several more tasks I recommend completing at this early stage. First, check the site deed. Watch out for covenants and/or easements. If you need to file a plot plan with a local official or agency, do so now, before you start work. Hire a licensed surveyor to check the site at this time. You must build within the established property lines and on the correct lot. Having a current survey of the lot provides a margin of protection for you as a contractor and for the property owner. Lawsuits are expensive and become even more so when you include your lost productivity. 

Figure 1-2 Basement location with respect to grade level  |  Figure 1-3 Cellar location with respect to grade level

Consider the Building Permit 

All contractors, including those in masonry and concrete, need to be aware of the potential problems with building permits. In most areas, no work may begin without a permit in hand. Failure to comply with permit-issuing procedures or the terms of the permit itself can lead to heavy fines. Worse yet, these fines are often retroactive to the date that construction began. 

Once you have a building permit, you'll notice it lists specific required inspections. These happen throughout construction as specific tasks are completed. It's your responsibility as a contractor or subcontractor to notify the inspector's office whenever your work nears the point of needing an inspection. Always give the inspector's office as much advance notice as possible. 

That way, work won't be held up while you wait for an inspection.

Issuing a certificate of occupancy is the final step in the inspection/permit process. This certificate shows that the construction covered by your budding permit is complete. It also certifies performance and passing of the final inspection.

Meeting the Standards

If you and your company undertake large projects, you'll probably be required to apply standard references. A standard reference, or a standard, is a specification, code, guide or procedure recognized and accepted throughout the industry. Some organizations that issue standards that apply to concrete and masonry construction are the American Society for Testing and Materials (ASTM), American National Standards Institute (ANSI), American Concrete Institute, National Concrete Masonry Institute and the Brick Institute of America.

Doing a Site Survey

We've already touched on the reasons for having a survey made by a licensed surveyor before any work is started. At this point I want to mention several good reasons for making your own survey as well.

Double-checking the setback against what the code requires is a smart move. Why? If there's an error, a building inspector is sure to spot it and slap a stop work order on the whole job site. Then you'll find yourself embroiled in legal action with the city, the general contractor, the land owner or all three. Double-checking the separation distance against what the code calls for is another good idea. Here again, an error in measurements is likely to lead to a dispute that ends up in court.

Doing your own surveying gives you familiarity with the site that you just can't get any other way. Plus, this early survey gives you a head start on the survey work for the foundation.

Both of the measurements just mentioned are easy to check. Do it! At this point any error you find can be fixed on paper. All it takes is a minute or two and your eraser and pencil. Fixing an error like this after you've started work costs far more. In fact, it could cost you your business.

While you're checking the site plan, give some thought to where you'll store materials on this job site. Remember, they're heavy. You can't pile them just anywhere. Take the time to check the site plans for underground tanks. At the job site, check any paved areas. Can they withstand the materials' weight? Also be sure you don't overload your vehicles - that's likely to cause an accident. Figure 1-4 shows the weights of the most common materials you'll use as a concrete or masonry contractor. Some of these figures will vary with the material's moisture content or texture of the material.

Soil Surveys and Analysis

Before you plan, let alone build, footings, foundations or walls, you need to know if the soil can support the structure. This is called the loadbearing capacity of a soil, and it varies with the kind of soil. How do you find out what kind of soil you're working with on a job site?

The U.S. Soil Conservation Service's soil survey for the area is your best bet. Their surveys cover all the information you need, and more. The Soil Conservation Service collects soil, climate and geographic data worldwide. Their maps plot this data over the top of an aerial photograph. They also publish written reports to match the mapped areas, which have even more detailed data. But the maps alone usually have all the information you'll need. They show.

• soil types

• soil pH

• soil's grain size

• depth to bedrock

• soil permeability

• boundaries between soil types

• seasonal high water table levels

The maps and reports aren't very expensive and you can order copies by calling (202) 205-0026 or writing to:

Superintendent of documents
United States Government Printing Office
Washington, DC 20402

Figure 1-4
Weights of common construction materials

If there's an agricultural extension bureau in the area, you can visit their office. The staff there can often answer your questions about local soils. They may also have maps that cover the information you need.

The best foundation-bed soil is one that:

• supports the building's weight

• doesn't swell when wet

• doesn't shrink as it dries

• isn't affected by frost heave

You're probably not going to find that ideal foundation bed soil. What you hope to find is the next best thing: a dry, well-compacted, sandy clay soil. Figure 1-5 lists some common soils and their loadbearing capacities.

Let's look at different kinds of soils now. We'll see what sorts of problems there are and how you can deal with them.

Rock

Rock isn't always bedrock, although it's easy to mistake a thin layer of rock for bedrock. Under the layer of rock is a bed of soft clay or sand and that's what the building really rests on. But can a bed of soft clay or sand support the building? Take another look at Figure 1-5. The loadbearing capacity of soft bedrock is 16,000 lb/SF. But soft clay, at best, has a loadbearing capacity of only 2,000 lb/SE

Here's another pitfall that catches beginners: mistaking a large, buried boulder for solid bedrock. This isn't a safe bed for footings because the boulder may break loose when the weight of a building is added.

Sand swells or flows when wet. Then, as it dries, it shrinks and settles. All of these (settling, flowing, swelling and shrinking) are bad news. Footings can be ruined by any movement. The only time sand is safe to build on is when the moisture level is stable. If that's not the case, you can bet on the sand moving sooner or later.

Clay

This soaks up moisture like a sponge. And, like a sponge, clay soils expand as they take in more and more moisture. Footings and foundations can be lifted right up by this swelling action. And clay is slippery and unstable when it's wet. Add some weight to a footing on a bed like this and the soil squeezes right out from under it. That's not good. The foundation will either fail or become so unstable that the building won't be safe. But you can raise a clay soil's loadbearing capacity by improving the soils drainage. You just add a layer of gravel to the top of the soil and then compact both soil and gravel.  

Figure 1-5
Loadbearing capacities of common soils

Peaty or Spongy Soils

Peaty or spongy soils need specially-designed foundations. When it comes to planning foundations or structures for a site with soil like this, you're out of your depth. It's a job for a structural engineer, not a mason.

Fill

Avoid fill if possible. if it's very well-settled there's a chance you won't have too many problems now or later. But differences in the depth and makeup of fill make it settle unevenly. Fill made from lots of different materials may have as many different loadbearing values as it has materials.

Acid or Alkali? What pH Testing Tells You

I mentioned that soil pH (a measurement of relative acidity or alkalinity) is one of the pieces of data given on sod maps. As a mason you need to know the pH of three things on the job site:

• soil

• ground water

• water used for mixing

If the water or soil's pH is less than 7, it's acidic. The lower the pH, the more acidic the soil or water. For example, a soil with a pH of 6.5 isn't very acidic. However, a soil with a pH of 4.5 is very acidic and may need special handling.

At the other end of the scale are pH values greater than 7. Soil or water in this range is alkaline. The higher the pH, the more alkaline the water or soil. What do you care if the soil or water is acidic or alkaline? Ground water or soil with a pH of 9 will quickly break down concrete or mortar made with Type I Normal portland cement. That's why you care. You'll have to use Type II, or better yet, Type V portland cement in the concrete and mortar. You'll see in the next chapter that these types of portland cement are sulfate resistant.

A pH of 7 is neutral. Something with a pH of 7 isn't acid or alkaline, but it's not a likely pH for soil or ground water.

Drainage

Most state health departments require safe sanitation practices for drinking and waste water. If you're budding in an area without sewers, make sure you know all the regulations involved. If you can, take a look at your job site in spring or during wet weather when the water table is at or near its peak. This is the best and easiest time to spot any problems with drainage, such as areas where water collects or places where seepage might be a problem later on.

To test the drainage, you can make a percolation test. This test will tell you how well wastewater will disperse into the soil. Here's how:

1. At the job site, dig a hole. If you can't do this test in wet weather when the water table is high, saturate the hole with water before you do the test. Where I live the hole must be 2 feet deep and 18 inches in diameter. Check the regulations in your area.
   

2. Fill the hole with water. Then time how long it takes the water to drop I inch, 2 inches and 3 inches. Use a yardstick to measure the water.
   

3. Do steps 1 and 2 again and average the results. I look for about 5 to 7 minutes per inch.

If the water level drops quickly, it may mean that wastewater could flow into drinking water at some distant location. If it drops slowly you may have poor drainage. Be sure these problems are solved at the beginning of the job. They can be very expensive later on.

Frost Heave

Frost heave describes the way soil is lifted up and disturbed when the water in it freezes. Water expands (by about 9 percent of its volume) when it freezes and pushes everything up. The soil in an area usually freezes to a certain depth and rarely below that. This depth is called the frost line. Below the frost line the soil isn't affected by the freeze-thaw cycle, so that's where you want to put the footings.

Surveying for Footings and Foundations

After all inspection work is complete, the next step is excavating. A good excavator will use a transit or some other sophisticated leveling device to position and locate the tops of footings, foundation walls and retaining walls. Don't let any excavator eyeball your job. No man alive can get it 100 percent correct, especially if the job site is uneven.

Even after a good excavator finishes his work, you probably should use your own instrument to make sure all the forms are level. Out-of-level forms or forms not set to the correct starting height will make it hard for any mason. For example, all mortar joints should be no more than 3/8 inch thick for structural strength. It's a bad practice for a mason to use thick joints to make up for depressions. And it uses up a lot of mortar. On the other hand, if a mason has to cut blocks to fit humps or correct the elevation on the first course, he'll use extra time and produce a lot of broken pieces.

Surveying Equipment

The surveying work you'll want to do calls for two basic tools: a transit level and a graduated leveling rod. Let's discuss both tools a bit more before we start telling you how to use them.

Transit Level

There are many different types of this precision measuring instrument. At the top of the scale, in price as well as precision, are electronic levels with such features as automatic leveling, laser-guided targeting and digital readout/input. However, most masonry and concrete contractors don't need this much precision. A transit is probably adequate for your surveying needs. A transit level has three main parts: the telescope, the leveling vial, and the circle.

Telescope (or scope)

This is a precision sighting optical device. It makes the images you see through it bigger. You take a sighting on a point simply by centering it in the vertical and horizontal cross hairs of the scope.

Leveling vial

This is a bubble-type level that works just like the bubble in an ordinary carpenter's level. However, it comes in different sensitivities. If you need precise readings, you'll need a sensitive leveling vial on the transit.

Circle

The horizontal circle is part of the plate that the scope rotates on. The circle, vertical or horizontal, is basically a scale that measures angles in degrees, marked by the divisions on the circle. There are 360 degrees in a circle. More precise transit levels have a second scale, called a vernier. A vernier lets you mea- sure angles more precisely because it divides degrees into minutes. There are 60 minutes in a degree. The best and most precise transits have a second vernier that divides minutes into seconds. There are 60 seconds in a minute.

The first step in any surveying operation is to center and level the transit. Follow the instructions in the manufacturer's user's manual. Generally these manuals are quite complete, clearly written and well-Illustrated. Your manual is the best resource for information that's specific to your instrument. Read it, use it and take care of it.

If you make readings using an out-of-level transit, the readings won't be true. Surveying with an out-of-level transit is a waste of time. Carelessness here can cost you everything, especially if it results in a stop work order for the whole project.

Graduated Leveling Rod (or Rod)

This is the second of your basic tools for surveying work. In a pinch, an ordinary 6-foot rule might work. But a rod is better because it's longer, by 4 to 9 feet, and it's easier to read accurately from a distance. The background color of a rod is white. Divisions for feet are in large red print while the other divisions are in black print. There are two types of rods which vary in the type of divisions used. Figure 1-6 shows an architect's rod. The divisions marked on this type of rod are feet (in red), and inches and eighths of an inch (in black). The engineer's rod is shown in Figure 1-7. The divisions marked on this rod are feet (in red), tenths of a foot and hundredths of a foot (in black).  

Target

This usually comes with the rod but once again you've two choices: the oval vernier or the snap-on target. Both kinds of targets have cross hairs and both work by sliding up and down the rod. Figure 1-6 shows a target on an architect's rod. Use the target's cross hairs to pinpoint elevation readings on the rod's scale.

I've known masons who use both sorts of rods as well as both types of targets in any combination. Choose the equipment you prefer or are most comfortable using.

Survey Teams

It usually takes at least two people to take a reading with a transit and rod. You'll need someone to hold the pole and move it around as necessary. Have an assistant (or rod holder) do these tasks, following your directions. Make sure the assistant holds the rod as shown in Figure 1-8 with the fingertips, taking care not to cover the scale.  

Sometimes you and the assistant will be so far apart you can't communicate with each other easily. If you're not equipped with electronic transceivers, you'll have to use hand signals. Figure 1-9 shows the most common hand signals for surveying work. There aren't many of them and most are pretty obvious, so they're easy to learn. Remember, both members of a surveying team must use the same signals for hand signals to work.

It's possible for one person to do surveying alone. You can take the sightings and make the rod readings with what's called a self-reading rod. The one-man system sometimes is faster and it will save you an assistant's wages. Look at the survey needs of each job before you choose between a team, or soloing on the surveying work. Estimate the time you'll spend trotting back and forth moving the rod. Balance what your time is worth against the wages for an assistant.

Figure 1-9
Standard surveyors' hand signals

The Question of Units

The measurements you'll find on site plans for heights and linear distances are usually in units of whole and decimal parts of a foot. The dimensions you'll find on building plans and blueprints are usually feet, inches and fractional parts of inches for units. Here are a few tips on how to convert between these two Systems:

• 8 one-hundredths of a foot (written as 0.08) is about 1 inch

• 1/8 inch is about 1 one-hundredth of a foot (written as 0.01)

Figure 1-10 lists inches and the most common fractions as decimal parts of a foot. Use it to find decimal equivalents in feet alone for measurements that are in inches and fractions. On the next page are a few examples.

Figure 1-10
Converting inches and fractions of inches to decimal equivalents in feet

Example 1

Find the decimal equivalent, in feet alone, for 2 feet 7-1/8 inches.

1. Find 7 in the column under the heading Whole inches.
   

2. Read across the 7 row to the column labeled 1/8 under the heading Fractional parts of an inch.
   

3. The value listed there (0.59) is the decimal equivalent, in feet alone, for 7-1/8 inches.
   

4. Now add the 2 feet to get the decimal equivalent in feet alone, 2.59 feet.

Example 2

Let's take one more example. What is 8 feet 4-1/2 inches in feet alone? Remember not to consider the 8 feet until the end.

1. Find 4 in the column labeled Whole inches.

2. Read across the 4 inch row to 1/2 in the column under the heading Fractional parts of an inch.

3. The value, in feet alone, for 4-1/2 inches is 0.38.

4. Add the 8 feet to get the decimal equivalent in feet alone, 8.38 feet.

Benchmarks and Elevations

Most buildings you work on as a masonry contractor have all the elevations specified. The elevations are based on a known elevation, called a benchmark. Usually one benchmark is enough, but on large jobs it's helpful to have several. The best benchmark is one that's easy to spot and difficult to move, like a bolt on a fire hydrant, the corner of a stone monument or a metal spike driven into a tree root. There's one final feature that's important in choosing a benchmark. Be certain it's located a good distance away from any of the construction action.

Keep accurate and up-to-date records of your survey work for each job. Good record keeping is a hallmark of a good businessman. It's also the best form of insurance you could possibly have. Finding the data later will be easier and you'll know it's current.

Finding Elevation Differences

You'll often have to find the difference in the elevations of two points. Let's work our way through a few examples to see how to do it.  

Figure 1-11
Finding the difference in elevation of two points

Example 1

For this first example let's assume you can see both points from one location. Set up, center and level your transit there. Then take readings of both points. The difference between the two readings is the difference in their elevations. We'll use Figure 1-11 to demonstrate this basic technique. Remember there are two questions here. First, which is higher, point A or point B? Second, how much higher is the higher point? It's obvious, from looking at Figure 1-11, that B is higher than A. But it often won't be so obvious on a job site. Here's how it works:

1. The reading for point A is 69"

2. Expressed in feet only, that's 5.75'

3. The reading for point B is 40" or 3.33'

4. To find the difference between these elevations, subtract 3.33 from 5.75 to get 2.42

So point B is higher than point A by 2.42 feet, or 29 inches.

Example 2

Let's look at Figure 1-12 for a problem that's a little more complicated. Taking a reading on point C is no problem. Point D, however, is located on the underside of the floor joist, above your line of sight. Let's see how you find its elevation, and then find the difference between the two elevations.

1. The reading for point C is 4' 6-1/2"

2. Expressed in feet only, that's 4.54'

3. To take an elevation reading for point D, place the foot of the rod against point D on the bottom side of the floor joist. That's right, hold the rod upside down, and then take your reading.

4. The reading for point D is 7' 9-3/8" (above line of sight)

5. Expressed in feet only, that's 7.78'

6. To get the difference in elevation, add the two elevations (4.54' and 7.78') to get 12.32'

So point D is higher than point C by 12.32 feet.  

Figure 1-12                                   Figure 1-13
Finding the difference                  Finding the difference
when one point                          when two points
is above the line of site              can't be observed from
                                                    one step

Example 3

Let's look at one more example. This time we'll assume that the points are so different in elevation that it's impossible to make sightings on both from one transit setup. We'll use Figure 1-13 for this example, and we'll find the elevation difference between point E and point H. This example also uses two new terms: plus sight and minus sight. Plus sights are readings taken from a point to the line of sight. Minus sights are readings taken from the line of sight to a point.

In this example, you'll use three transit setup locations to find the difference in elevation. At each of these locations, take two readings - one plus sight and one minus sight. Then add the plus sights from the three locations together. Then add the minus sights together. If the sum of the plus sights is larger, point H is higher than point E. If the sum of the minus sights is larger, point E is higher. To find the elevation difference, follow these easy steps:

1. Convert all measurements to feet only
   

2. Add all the plus sights together :
   2.59'+ 1.81'+ 7.85' = 12.25'
   

3. Add all the minus sights together:
   8.38' + 9.97' + 1.2I' = 19.56'
   

4. Subtract the total minus sights from the total plus sights to find the difference in elevation point E to point H:
   12.25' - 19.56' = -7.3I'

The minus sign tells you point H is 7.31 feet lower than point E.

Note: When you convert feet and inches to feet only, the resulting value is an approximation. If you work out this problem using feet and inches, there's a 1/4" difference. The precise answer would be -7' 3-1/2".  

Figure 1-15
Building layout and batterboard setup

Staking Out a Building

This process is a good deal more than just pounding four stakes into the ground. It's also an important part of your early on-site survey work. We'll go through the process in stages, and take the procedure step by step. We'll refer to Figure 1-14 often, so let's begin by identifying its main features.

• Points A, B, C and D mark the corners where you place the stakes.
  

• The shaded area shows the future location of the foundation.
  

• Lines AB, BD, DC and CA are the building lines.
  

• The diagonal dashed lines, AD and BC, mark measurements you use to check for squareness.
  

• The right-angle shapes, shown outside the building lines at the corners, are the batterboards. Each N marks the location of a nail driven into the top of the batterboard.
  

• The lines that extend the building lines out to each nail location show part of the path followed by the string lines. The rest of a string line path matches that of the building line.

Let's also assume we know:

• line AB is the building's frontage

• the location of point A

• point Bs direction, relative to point A

• all angles are 90 degrees

• the length of all four building lines

To stake out the building:

1. Level and center your transit on point A
   

2. From A, sight on point B. Do that by turning the transit 90 degrees to the left.
   

3. Set point B at the known distance from A. Mark point B with a corner stake.
   

4. Leaving the transit at point A, sight on point C, That means you turn the transit 90 degrees to the right.
   

5. Set point C at the known distance from A. Mark point C with a corner stake.
   

6. Move the transit to point B. Center and level the transit on point B.
   

7. From B, sight on point D by turning the transit 90 degrees to the left.
   

8. Set point D at the known distance from B. Mark point D with a corner stake.

Before you move on to setting up the batterboards, stop and check the work you've done so far. There are two ways to double-check this part of your work. The first way is to compare the lengths of a set of parallel sides. Measure the lengths, for example, of line CD and line AB. If they're equal, then your work's accurate.

The second way to double-check the layout is to compare the lengths of the diagonals. In Figure 1-14, these are the dashed lines AD and BC. I recommend using the diagonals method because it also checks the layout for squareness. Equal diagonals mean you've set the corners accurately and square. If any of the four angles isn't 90 degrees, the diagonals won't be equal. If your diagonals aren't equal, go back and check the angles with your transit. What does it mean if all four still read exactly 90 degrees? The problem is probably an out-of-level transit setup. Start over with step 1 and this time be more careful!

Placing Batterboards

Now that you've set and stacked your four corners, let's move on to setting up new batterboards. Masons use batterboards to define building lines. Your carefully marked corner points A, B, C and D all disappear when the foundation is excavated. But the string lines that you run from the batterboards extend the building lines and cross each other exactly over the corner points. They make the job of re-establishing the corner points a piece of cake. The whole reason batterboards and string lines work is that they're set up outside the building lines. Excavation or other site work won't happen near them, so their positions aren't disturbed. A comfortable separation, the distance between the batterboards and the building lines, runs about 4 feet.

Set up the batterboards shown in Figure lows:

1. Level and center the transit in a convenient spot near the building's center.
   

2. Set three posts, the batterboard uprights, about 4 feet out from the building lines at each corner.
   

3. Take sightings at each corner on the foundation's top.
   

4. From this reading subtract the clearance - the distance between the foundation top and string lines.
   

5. If the result isn't a whole number of feet, add as needed to make a whole-foot number and set the rod target for this elevation. Adjusting this elevation to read as a whole number of feet makes it much easier to sight with the transit in the following steps.
   

6. Holding the preset rod at each of the batterboard uprights (posts), raise or lower the rod and center the target reading in the transit's cross hairs.
   

7. Mark each post with the location of the rod's foot. This marks the correct position for the top edges of the batterboard crosspieces.
   

8. Attach the crosspieces to the uprights following the markings.

The next step is setting the nails in the batterboard to attach the string lines:

1. Level and center the transit over each corner position.

2. Take sightings in turn on the two adjacent corner points.

3. Mark the points on the top edge of the batterboard.

4. Drive a nail into the batterboard at each mark.

Now, for the final step, simply run the string for the string lines from nail to nail. The string lines extend the building lines out to the batterboards and crisscross exactly above the corner points. It's easy to check the positions of the string lines. Take a look at Figure 1-15, then just follow these steps:

• Tie a plumb bob to a short length of line.

• Attach the line to one of the string line crossing points.

• Lower the plumb bob until its tip touches the top of the corner stake.

Figure 1-15
Checking batterboard and
string line placement

Your string line and batterboard setup is correct if the plumb bob tip touches the corner stake at its center.

Measuring and Laying Out Horizontal Angles

All of the surveying measurements we've discussed so far have been for vertical angles. The steps for measuring a horizontal angle are somewhat different. As an example we'll use the angle shown in Figure 1-16. This is angle EFG and point F is the pivot point. Here goes:  

Figure 1-16 Horizontal angle of 62 degrees

1. Level and center the transit over point E
   

2. Attached to the transit's circle you'll find the horizontal clamp screw. Loosen this screw.
   

3. Turn the scope and sight on point E.
   

4. Align point E with the scope's horizontal cross hair.
   

5. Tighten the horizontal clamp screw.
   

6. Turn the tangent screw to align point E with the scope's vertical cross hair.
   

7. Reset the circle's scale, by hand, to zero. Either the circle's scale or the index (pointer) moves. This varies from transit to transit.
   

8. Loosen the horizontal clamp screw again. (Be careful not to move the circle in the process.)
   

9. Turn the scope and sight on point G.
   

10. Align point G with the horizontal cross hair.
    

11. Tighten the horizontal clamp screw. (Remember not to disturb the circle.)

12. Turn the tangent screw to align point G with the scope's vertical cross hair.
    

13. Read the value of the horizontal angle turned on the circle's scale. See Figure 1-17.

Out on job sites, you'll find most angles are 90 degrees. With that in mind, here's a quick run-through to show you how to set this angle. We'll use angle HIJ in Figure 1-18. Let's also take a shortcut by assuming that the locations and elevations of points H and I are known. Point I is the pivot point. We need to find point J. Here's how to set this point:

1. Center and level the transit over the pivot point 1. Turn the scope and sight on point H.

2. Align point H with the scope's horizontal and then the vertical cross hairs.

3. Reset the circle's scale, by hand, to zero.

4. Turn the scope and sight on point J.

5. Align point j with the scope's horizontal and then the vertical cross hairs.

6. Read the horizontal angle that was turned from the circle's scale.

Sometimes you'll want more accurate readings than these. Why? An angular error equaling I degree over a distance of 100 feet causes a 1-3/4 foot error. But a transit with a vernier divided into minutes gives much more accurate readings. How much more accurate? Sixty times as accurate, since I degree is made up of 60 minutes. An angular error of 1 minute over 100 feet causes an error of only 3/8 inch. It's unlikely that you'll ever need the level of accuracy that's possible using a vernier divided into seconds. An angular error of 1 second over 100 feet results in a total error of only 1/200 inch.  

Figure 1-18 Horizontal angle set for 92 degrees

Reading a Vernier

Reading a vernier takes some practice. Start by looking at Figure 1-19. The vernier (minutes) and the circle (degrees) scales have been set to zero by aligning their indexes. The index is the zero on each scale.

On the vernier there's an R to the left of the 60-minute mark and an L to the right of a second 60-minute mark. What's going on? The index at the zero point divides the vernier in half and makes two scales. Read from the R side of the scale for angles turned to the right or clockwise. Read from the L side of the scale for angles turned to the left or counterclockwise. Don't worry if it seems backward at first to have the L side of the scale on your right and the R side to your left. This is correct. Your vernier isn't on backwards. The strange- ness wears off with practice.

Now that you know the parts of a vernier, let's talk about how to read one. The vernier's index is also a pointer, or the marker you use to read degrees from the circle scale. The next question is: What marker do I use to read minutes from the vernier scale? The answer brings us, at long last, to the secret of the vernier!

The division marks on these scales (vernier and circle) are very finely calibrated so that no matter what angle you turn with the transit, there will always be one, and only one, pair of division marks in precise alignment. The first step in reading minutes for an angle is to find this unique point. Then you simply read the minutes value that's marked on the vernier's scale. Sounds pretty easy, doesn't it? All you need now is a bit of practice at reading the fine divisions on the scale.

That brings us to the second point. A vernier scale with a separate mark for every minute would be quite difficult to read. For that reason, in the following examples, we'll use two different vernier scales. The first is a 5-minute vernier, shown in Figure 1-20. This means that each division represents 5 minutes of a degree. The second example uses a 15-minute vernier, shown in Figure 1-21. Each mark on its scale represents 15 minutes of a degree.

Example 1

For this example we'll use the 5-minute vernier in Figure 1-20. The transit is turned for an angle to the left. Here are the steps:

1. Read degrees from the circle's scale as marked by the vernier's index V The answer is 44 degrees.
   

2. The angle was turned to the left. So, on the L side of the vernier scale find the pair of exactly aligned division marks, and read the minutes.
   

3. The alignment is at the vernier's fourth mark to the left from 0 (the index).
   

4. Since this is a 5-minute vernier, the fourth division from 0 equals 4 x 5. That's 20 minutes.
   

5. Combine the degree reading with the minutes reading. The answer is an angle of 44 degrees 20 minutes turned to the left.

Example 2

For our second example, the angle is also turned to the left, but this time we'll use the vernier in Figure 1-21, with a 15-minute scale. What's the angle in degrees and minutes?

1. Read degrees from the circle's scale as marked by the vernier's index V The answer is 44 degrees.
   

2. On the L side of the vernier scale, find the pair of exactly aligned division marks and read the minutes.
   

3. The alignment is at the vernier's third mark to the left from 0 (the index). The answer is 45 minutes.
   

4. Combine the degree reading with the minutes reading. The answer is an angle of 44 degrees 45 minutes turned to the left.

The Vertical Vernier

You use a vertical vernier to read the minutes (and seconds if the transit has two vertical verniers) of an angle that's turned up or down from the zero point. They're read in the same way as horizontal verniers. The vertical circle (and the vertical vernier) are usually located off to the side of the scope. On a vertical vernier, the scale to the right of the index is marked up and the scale to the left of the index is marked down. You read minutes for angles of elevation on the up side of the scale. You use the down side of the scale to read minutes for angles of declination.

All this information on surveying may seem a bit complicated and not particularly important to your work. But checking out these details could keep you out of trouble with the building inspectors.

Now that you've gotten your feet thoroughly wet, let's dive into the real substance of this book - concrete and other kinds of masonry work.