House Construction (Foundation Plans)

Objectives:►Compare various construction techniques/

materials►Design a foundation plan based on a 2-story

home floor plan design►Analyze how the weight of a house affects

the foundation

Video: House Construction Animation of Home Construction (3:47)https://www.youtube.com/watch?v=FQvFzdFIp08

Preparing a Lot for Construction► First, the lot is excavated (a

hole is dug) with machinery

► Reinforcement may be necessary. depending upon the size and load of the building as well as the ground soil conditions -- for example, if the ground is wet and is therefore prone to swelling. Reinforcement comes in the form of a mesh constructed from reinforced steel bars. These are laid at the bottom of the trench, slightly elevated by spacers to allow the concrete to flow beneath.

► Plot plans provide necessary dimensions required for staking out a house location on an empty lot

► The corners of the house are located and stakes are put into the ground

Preparing a Lot for Construction

► Stake out the house: Put a stake in the ground for each corner of the house

► “Staking” requires a measuring tape and contractor’s level

Preparing a Lot for Construction

► Batter boards are marks placed for use as references or guides during the initial excavation and rough grading of a building construction

► They consist  of  2 x 4 inch  wood stakes with a crosspiece of 1 x 6 inch lumber nailed to it

Preparing a Lot for Construction

Building a House on the Lot► The structure of a house carries the weight to its

supporting element - the ground. The structure is what makes the house stand up. A house is constructed from the bottom up.

► These are often called load-bearing elements or systems. (Here is the construction sequence): Footings Foundation Flooring Walls Ceiling Roof

Footings► This is where the house meets the ground. It’s the

first member of the load-bearing structural systems. Also called the “footer.”

► The footings are placed under all load-bearing parts of the foundation, i.e. piers, columns, foundation walls, etc.

Pouring Concrete Footinghttp://www.youtube.com/watch?v=Mq4kE9BbKvc

Footings► Footings are almost always

concrete poured into a trench and constrained by some kind of forms (often wood planks)

► Typical footing dimensions are: 8" deep and 16" wide. If the dimensions aren’t just right.

► Reinforcing the footing with steel rebars is helpful in strengthening the footing before the concrete is poured

Foundation► Consists of walls and other vertical elements

needed to support the floor (piers and steel columns)

► The foundation needs to bear a considerable amount of weight and provide a flat and level base for construction.

Foundation► To reinforce the foundation,

concrete is poured into the trench over a mesh layer.

► The strength of the concrete is determined by the calculations made during the design stage.

► Once the concrete is poured, it will need to be "tamped", which is the process of hitting the surface of the foundation with a plank of wood to remove trapped air that could compromise the strength of the concrete once dry.

Types of Foundations

T-Shaped

• A traditional foundation method to support a structure in an area where the ground freezes (Northern US). This method has stood the test of time.

• A concrete slab poured on the ground down at the bottom of the hole (also called “stem wall” foundations)

Types of Foundations

T-Shaped or Basement Construction

• A footing is placed below the frost line and then the walls are added on top. The footing is wider than the wall to providing extra support at the base of the foundation.

• We will be using this method for our foundation plans

Types of Foundations

T-Shaped or Basement Construction

• The foundation walls may be formed concrete, treated wood, or masonry (brick or concrete block)

• Concrete block foundation walls are typically 8 inches thick

• Video- How to build the walls (2:20)

https://www.youtube.com/watch?v=UbB5Cre3-ng

Types of Foundations

T-Shaped or Basement Construction

• Section Drawing through the center of a house showing basement foundation with footers and concrete block walls

• The only difference is the garage (will have a slab poured, b/c cars are too heavy for a basement!

Types of Foundations

Slab on Grade Construction

• No below-ground basement. Most popular in southern states, where ground doesn’t freeze. (Can be used in the north if it’s properly insulated.)

• Slab floor is poured as one single layer several inches thick. The slab normally rests on a bed of crushed gravel to improve drainage.

Types of Foundations

Slab on Grade Construction

• It is waffle-shaped steel that is reinforced with a concrete sheet. A single layer of concrete is poured several inches thick.

• The slab is poured on crushed gravel to improve drainage.

Types of Foundations

Pier and Beam Construction

• Used in areas with heavy clay content in the soil, such as Texas & the Southwest

• Also called a “Crawlspace” foundation because underneath is an accessible space with limited headroom, between the soil and the bottom of the first floor.

• They typically have a concrete wall that goes around the outside with a wood floor that spans from one side of the wall to the other

Types of Foundations

Pier and Beam Construction

• Spaces are usually only 16 - 18 in. between the bottom of the floor joists and the soil

• Considered the most economical. The space underneath allows easy installation of plumbing and heating utilities for accessibility

• However, if the space isn’t insulated properly, water vapor can cause severe mold problems.

Types of Foundations House Construction Documentary (23:11 – stop after 5:00)https://www.youtube.com/watch?v=OTiWdnoAir4

Fast-Motion: Building the Foundation (Stop at 1:15)https://www.youtube.com/watch?v=C3iI6S7TuCA

Flooring

► Floor systems are either wood or concrete.

► The wood floor consists of the supporting members - beams and joists - and the flooring material, usually a plywood product.

Flooring

► Typically, there is a beam supporting the floor joists. The beam is supported by the foundation walls and intermittent piers or posts in the foundation (the latter must have their own footing).

► Beams are made of a variety of materials including wood and steel.

Walls

► Typically he walls are framed (assembled) on the ground, and then raised into place.

► The 2x4s (pieces of lumber) are placed 16-inches on-center, meaning that the center of one 2x4 is 16 inches away from the center of the next.

► Add plywood sheething layer for rigidity (bottom image)

Ceiling and Roof

► We will talk about those structural elements when we do our roof plans!

Foundation Plan (with dimensions)