The house Site

This slide shows preparation for the basement. New sand was added to aid in water drainage.

Concrete Forms

All the forms are in place. The concrete truck will come and fill the gap in forms with concrete. A compactor tool is used to remove air gaps in the concrete. The forms will stay in place for 24 to 48 hrs, depending on humidity, sunlight and temperature.

Footings and Wall

This slide shows concrete forms on top of a poured concrete footing. A 2x4 support holds the wall from falling. Crushed stone has been dumped on top of a perimeter drain and around the footing to permit water drainage from around the foundation. Water will drain through the rocks and into the pipe, then out the opening away from the building.

Footings

Inside of what will become the basement are more forms. These forms are set and will be underneath steel lolly-colums which support the girder. On top of the post is where the girders (beams) sit. These footings measure 24”x 24” x 12”. Each cement form is 24” wide.

Looking into the Form

Here is a view from the top of a form filled with cement. The bolts sticking out of the cement are “J” bolts. These bolts will be used to attach the sill plate to the top of the cement wall.

Preparation of the Floor

Notice the red machine, this is a sand compactor. Before the basement floor is poured, air bubbles and moisture is forced out of the soft sand. If air and moisture is left in the sand, the basement floor could look like your favorite frost heave road.

The Garage

This may look odd to you. But this dirt mound inside the walls will support the garage floor. Your car or truck is a lot heavier than anything you may put in your living room. Your truck is a good example of dead load. To support all this load sand is under the garage floor.

Perimeter Drain

In an earlier slide perimeter drain was mentioned. Here is a picture of the end of the drain. Water will come out of this and lead away from the structure.

Water Drainage

An earlier picture showed crushed stone over a perimeter drain. This photo shows where the perimeter drain ends. Notice that the drain pipe is rigid (does not bend) this allows the pipe to maintain its shape while soil and stone have been dumped on it. The pipe is perforated or has holes in it. The holes face up so excess water can fall into it and drain away.

The Forms Come Off

The forms come off the cement.The exterior concrete wall has been painted with a water barrier. Sand has been pushed against the concrete wall in preparation for the 1st floor deck.

Beam Pocket and Rebar

There is two 10” x 12” pockets left in the concrete wall. These pockets will support the ends of the girder. You may also notice a grid of dots, this where the ½” steel rebar has been placed in the soft concrete. Rebar serves two purposes, to hold the forms in place and to give concrete more support during the drying process. When the forms are pulled off, the ends of the rebar are removed leaving a “flat” surface.

Bulk Head

Notice a jog in the concrete wall and the height difference. This is for an exterior exit from the basement. This is called a bulk head. BOCCA code for our area requires an exterior exit from a basement, there is also a code for the amount of ventilation (exterior windows) required in a basement.

Here is a great view of basement windows and the water barrier. Notice the windows begin at the top of the concrete wall and hang down. The windows must be put in place when the forms go up. The black paint on the outside of the wall is a water barrier, not a vapor barrier. Concrete needs to breath. Think of this as a ski jacket and your skin. Your body needs to exhaust extra humidity, but does not need water from the outside.

Bulk Head Doors

Another great shot of the bulk head. A set of steel doors will sit a top of the short wall and angle up to the top of the basement wall. Notice the groove on top of the cement, this will hold the steel unit in place and provide a surface for a rubberized seal.

Garage Prep

Here is a shot of the concrete work for the garage. Notice the black plastic laying inside the walls, this is placed on the earth to insulate the ground from impending frost. If the ground freezes before a concrete slab can be poured it will crack and lift like a frost heave. The concrete protrudes from the ground a couple of feet. This keeps the wooden material away from moisture, rodents and insects.

Pressure Treated Sill Plate

My lovely assistant is pointing to a greenish colored board. This is a sill plate the first piece of wood. Since this wood touches a surface that could potentially be moist a chemically treated board is used. This board is pressure treated with a rot resistant chemical. It doesn’t taste very good either.

Vapor Barrier

I have mentioned water barrier now vapor barrier. Vapor is moisture, tiny droplets of water in a condensed location. Since concrete is a breathing substance it contains moisture. Wood does not last long in a moist environment, so a thin piece of foam is spread along top of the concrete wall. When all water is drawn from concrete it will dry and crumble, kind a like our skin.

Rim Joist

Here again is my lovely assistant squishy pointing to part of the floor system called the rim joist. These joist run parallel to the girder and cover the ends of the floor joists.

Sub-Floor

Squishy is now pointing (he’s hands on) to a thin layer between the rim joist and the shoe plate. This is the sub floor. Usually this material is tongue an groove, 5/8” thick and made of chip board. Structurally this layer gives the house lateral support. When each floor joist is bound by the sub-floor, side to side motion and flex is reduced.

Shoe Plate and Base Plate

Squishy is pointing to two members, the bottom one is the shoe plate and the upper is the base plate. These members are sometimes called double-base plate. These members are the beginning of the wall. Why two, well the bottom member is attached to the sub-floor and the rim joist with a 31/2” nail then the second is attached to that. This method insures that side force and movement of the structure does not cause a sheering or a vertical separation of the wall from the floor. “Physics and Math ”

Interior/exterior Walls

On the right a double shoe plate, all inside walls begin with 2 shoes (2x4 inside wall). The left is an exterior wall, notice here there is a single shoe. Outside walls require a single shoe plate and a double top plate.

Stairs

Here is a rough stairway. A stair system generally made up of 3 stringers, numerous treads and risers. Stairs begin at the rough floor and go through to the next floor. This means 8’ floor to ceiling plus 12” of floor system. Therefore stairs must travel up (y) 9’ and the tread depth is 9-11” (x). Using the formula y=mx+b (slope of a line) you can determine the angle of the stair system.

Header

Above all openings sits a header. Headers are structural elements which divert a load across a distance with the use of a larger element. The headers shown here are (2) 2” x12”.

Floor System

This floor system uses a steel I beam to carry the load across a distance. Steel will allow a greater span between walls. Joist hangers hold the floor system to the center beam. Joist run every 16” O.C. This system allows for a smooth ceiling without beams protruding below the 8’ ceiling height. The smaller wood strips running across the ceiling are nailers for drywall.

Elevations

This is a front elevation here you can see where the windows and doors will be placed, these are called a rough openings. There are also rakes on the gable ends of the roof where the overhang is supported.

Roof Rafters

These will be the members which will support the roof. The cut out will sit on top of the wall, which is often referred to as the birds mouth.

The Structure of a House

Stay tuned for the completion.