C-101, Site Plan

How to read this sheet

C-101 is the only sheet in this set drawn at an engineer's scale. It reads 1" = 20', which means one inch of paper is twenty feet of ground, and it is a decimal scale rather than a fraction of an inch to the foot. Everything on a civil sheet follows from that: distances come in feet and hundredths of a foot, not feet and inches, and elevations are decimals too.

Find the property line first. It is the long dash and short dash line that closes around the lot, and each of its four courses is labelled with a bearing and a distance. A bearing is read as a quadrant: the meridian letter, then degrees, minutes and seconds, then the quadrant letter. "S 04-45-49 E" means start facing south, swing four degrees, forty five minutes and forty nine seconds toward the east. The distance after it is the horizontal length of that course. Walk the four courses in order and you come back to where you started, which is what a surveyor means by a closed figure, and it is the first thing to check on any boundary drawing.

Next find the building. The footprint is the same 80'-0" by 40'-0" rectangle drawn on A-101, placed on the lot and dimensioned to the property lines. Those four dimensions are the setbacks: 40'-0" from the front line on Kestrel Avenue, 40'-0" from the side street line on Millbrook Road, 85'-0" to the east line, and 100'-0" to the rear line. A setback is a required minimum, and the dimension you see is what is actually being held.

Now read the ground. Contours are lines of equal elevation, drawn here at a one foot interval. Existing contours are dashed and proposed contours are solid, and where the two lie on top of each other nothing is being regraded. The numbers on the contours count up toward the south, so the site falls toward Kestrel Avenue, which is where the storm main runs. The benchmark near the north west corner is the fixed point every one of those elevations is measured from, and its elevation is stated on the sheet.

Watch the datums. A site elevation and a building elevation are two different measuring systems. Level 1 finish floor is 0'-0" on the architectural sheets and 100.50 here. Subtract to move between them, and never assume a number on a civil sheet and a number on an architectural sheet share a zero.

Finally read the utilities. Each run is drawn as a hidden line with its size and service written along it: 8 in W for the water main, 8 in SAN for the sanitary sewer, 15 in ST for the storm drain, gas and primary electric in Millbrook Road. Inverts are called out in text at the ends of a run, and an invert is the inside bottom of the pipe, not the top and not the centre. Gravity runs downhill from the higher invert to the lower one, and the slope note tells you how fast.