Residential Construction Unit 2- Site Work and Concrete Mr. Todzia

 Land must first must be surveyed so exact boundaries are know.  Surveys are done by licensed professionals called Surveyors.  Historically their work was done with instruments called Transits.  These used complex geometry, trigonometry and triangulation to determine bearings and distances. Surveys were calculated and drawn by hand.

 Modern day Surveyors use high tech. instruments called Total Stations.  A total station is an electronic/optical instrument used in modern surveying. It is an electronic transit integrated with an electronic distance meter to read slope distances from the instrument to a particular point.  Total Stations also use GPS to locate the instrument and to establish a point of beginning.

 Property lines are usually shown in Bearings.  A bearing is a direction and a distance. It would specify which direction a line would go and how far in that distance.  For example a property line might say:

 Surveyors use the Bearings and distances to label and describe the entire outer perimeter of the piece of land.  When the boundaries are officially determined, we then choose an appropriate house site.  Road access and topography are the next things to consider.

 Topography is the surface shapes and features of the earths surface.  Another name for a topographical map is a contour map  See contour map handout.

 What is represented by lines very close together?  What is represented by lines very far apart?  What is represented by looping lines?  What geographical feature is represented by lines forming a “V” that point down hill?

Construction requires preparation of the site Top soil removed and stored for later final grading Cut and fill may be required  Cut – The removal of natural soil or rock  Fill – The addition of soil or rock Final grading involves adjusting the slope of the site to provide adequate drainage photo courtesy of constructionphotographs.com

 Cut and fill should be balanced  May require several iterations photo courtesy of constructionphotographs.com

Calculations are performed to estimate the volume of soil to be added and the volume of soil to be removed Profile views document the difference between the existing grade and the final grade photo courtesy of constructionphotographs.com

 Why is land clearing and excavation so expensive?  Machines are expensive to operate or hire out  Materials are expensive to purchase and to truck in or out.

What machines are used?

What is this machine called?

 Foundation holes are usually dug with an excavator.  They are dug to a depth to accommodate the planned basement.  Common depths are 8 or 9 feet deep.

 After the holes are dug the soil is compacted using a compactor.

Usually 4 to 6 inches of crushed stone is laid at the bottom of the foundation and is also compacted. More or less stone is used depending on the water table

Footings are formed using conventional lumber and are typically 2 feet wide. They form a solid base to increase the surface area and bearing capacity under the foundation wall.

 Drainage is an important aspect of site preparations.  Footing drains, Basement floor drains and rainwater drains all need to be considered before concrete can be poured and backfilling is done.

 Drains are to gravity feed water to a location down hill that can sufficiently take away the run off.  Gutter drains are to be made out of solid PVC pipe primed and glued together.  Footing, floor, curtain, and French drains are all made of perforated PVC pipe  The above listed drain types collect surface and ground water through the perforations in the PVC pipe and take the water away from that location.

 All inspections must take place before concrete is poured and backfilling is done.  Why?  What is the inspector looking for?