OutdoorStructures.pdf

Before building any outdoor structure

near a neighbor's land, be sure you know

exactly where your property lines lie.

Start by studying the lot plat, or map, that

was furnished with the title to the land.

When mapping the land, the surveyors

drove metal stakes into the ground at the

corners of the plot to serve as property

markers. If you can locate one of them,

your property map and a little basic

geometry will enable you to find the

others. You can determine the boundaries

by driving stakes next to the markers,

then stretching string between the stakes.

Once the boundaries are established,

a few simple surveying techniques and

tools will enable you to map the location

and size of the structure you want to

build. Distances can be measured fairly

accurately with a mason's line, wooden

stakes, and a carpenter's tape measure,

but keep at least 12 inches from a proper-

ty line when siting a structure to avoid ac-

cidentally straying onto a neighbor's land.

To sight lines for pouring foundations, or

to establish perfect parallels or right an-

gles to property lines, use a transit level.

Tape measure

Maul

Shovel

Magnetic stud finder

Transit level

Before positioning or excavating

trenches, find the locations of

underground obstacles such

as dry wells, septic tanks, and cesspools,

and electric, water, and sewer lines.

Wooden stakes

Tall poles

Powdered chalk

Mason's line

Clear plastic hose

Working from two known markers.

• With a maul, drive a wooden stake next to a known

marker. (Property markers may be lost in undergrowth or a

few inches underground.)

• Attach a length of mason's line equal to the distance be-

tween the known marker and the lost marker, as indicated

on your property map.

• Mark an arc on the ground near the lost marker with

powdered chalk (right).

• Repeat the procedure at another known marker.

• Dig for the lost marker at the intersection of the arcs (inset).

Working from a single marker.

• Mark an arc on the ground with chalk over the approximate

location of the hidden marker (above).

• Brush a magnetic stud finder along the arc (left). When the

stud finder's needle deflects, dig for the marker. If the stud finder

does not work, try using a metal detector. The final recourse is

to call in a professional surveyor to reestablish the property lines.

Sighting a straight

line over a hill.

• Drive a stake at both the

starting and unseen points.

• Stand at one stake, station

a helper at the other, and

have two more helpers hold

tall poles in between at

points where the tops of

the poles can be seen from

both stake positions (right

and inset).

• Sighting from your stake,

signal the pole holder near-

est you to move until the

two poles are in a straight

line from your view.

• Have the helper at the

unseen point repeat the

procedure with the second

pole person.

• Alternate sightings until

the poles appear in line from both positions.

• Connect the four points with mason's line.

Finding level points on a slope.

You can find a point on a stake or post

that is level with a mark on another by

using a water level or a clear plastic

hose partly filled with water.

• Make a mark at the desired or

known height on the first post.

• Position the hose between the posts

as shown. Hold one end a few inches

above the mark you have made and

have a helper hold the other end at

about the same height.

• Fill the hose with water until the

level reaches the mark.

• Make sure there are no air bubbles—

if there are, block and lower one

end to allow the bubble to rise to

the surface.

• Finally, mark the second post at the

water level in the hose (left).

Anatomy of a transit level.

This professional surveying tool is

essentially a tripod-mounted movable

telescope with precise scales for read-

ing vertical and horizontal angles. The

20-power telescope pivots at its center

for vertical measurements and the entire

mounting carriage rotates on the under-

carriage for horizontal ones. A small

spirit level mounted under the telescope

assists in leveling and plumbing the

instrument. A hook for a plumb bob

hangs from the base plate; the under-

carriage slides over the base plate to

position the bob over a stake or marker,

and four leveling screws are used to set

the level. Angles are measured on ver-

tical and horizontal scales; when only

horizontal measurements are needed,

as on the following pages, a pair of

levers locks the telescope in the level

position. Slow-motion screws allow

you to zero in on the sighting stake

by turning the telescope; clamp screws

then lock the transit in position.

In addition to setting straight lines or

right angles (pages 12-13), a transit

level can be used to measure a

range of horizontal and vertical an-

gles. Horizontal angles are read on

a 360-degree circular scale divided

into four 90-degree arcs (top left),

vertical angles on a 90-degree arc

(bottom, left). Small auxiliary scales

called verniers serve as pointers for

the main scales and give readings in

sixtieths of a degree, or minutes.

If the zero mark on

the vernier falls between

two degree marks on the

main scale, read the lower mark

and use the vernier to calculate

the fraction in minutes. Reading

upward from the degree mark, find

the mark on the vernier that lines up

perfectly with a mark on the main

scale. Count the vernier spaces

between the two main-scale marks.

Each space stands for 5 minutes;

multiply the number of spaces

by five to get a

reading in minutes.

The sighting at right

reads 17 degrees

15 minutes.

1. Positioning the tripod.

• Spread the tripod legs over a marker to be used as a starting

point. Move the legs one at a time until the plumb bob hangs

no more than 1/4 inch from the center of the marker.

• Loosen the screw under the base plate and shift the transit

level so the plumb bob is directly over the center of the stake.

• Tighten the base-plate screw.

2. Leveling the transit.

• Set the vertical scale to zero.

• Loosen the horizontal clamp screws and turn the

telescope until it aligns with one pair of leveling screws.

• Turn these screws until the bubble in the level is

centered (left).

• Rotate the telescope 90 degrees to align it with the

other pair of screws; adjust these screws the same way.

• Repeat as needed, making minor adjustments so the

bubble in the level remains centered as the telescope

swings full circle.

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