BCTT 60B
Week 1
Lecture
This week’s lesson will cover:
In the past there have been many different methods for framing houses. While some of them are rarely used in today’s construction industry, it is beneficial to have a general understanding of them. There are many factors that determine which framing style should be used, including:
The following are the different classifications of framing methods:
The framing method most widely used in residential construction is the platform frame. This is also known as the western frame. An example of platform framing can be seen on page 5.3 of the textbook. One advantage to this method is that the walls are constructed while lying on the subfloor. Once a wall is completed it is tilted up and secured in place. This allows workers to safely work on the floor. A disadvantage to this style is that it is prone to settling. Settling is caused by the shrinking of load-bearing members within the frame.
Results of settling include:
- Cracked plaster
- Uneven ceilings and floors
- Poorly fitted windows and doors
While settling is inevitable, it can be minimized if well-dried lumber is used, the foundation soil is compacted, and the frame is properly braced.
The balloon frame method is not commonly used anymore, but it may be required by local codes for areas with frequent hurricanes. There are also a number of buildings still in use that have a balloon frame. With this style the studs run from the sill all the way to the rafter plate. An example of balloon framing can be seen on page 5.5. Notice how the studs and first floor joists rest on the sill. Also there are ledgers notched into the studs for the second floor joists to rest on. Braces are also notched into the outside of the studs to provide rigidity. Firestops must also be installed. Disadvantages to this style include high lumber and labor costs.
Post-and-beam framing is used in heavy timber buildings. This method uses fewer framing members spaced farther apart. This requires large timbers for joists, posts, and rafters. Post-and-beam framing provides the ability to place large glass areas in a structure. An acceptable amount of bracing must be provided for rigidity.
All the information needed to successfully build a structure is found within the blueprints. One section of blueprints is the architectural drawings, which include:
The foundation plan is a drawing that shows the location and dimensions of footings, grade beams, foundation walls, and piers.
The floor plan is an aerial view of the building, which shows the layout of the rooms on that floor. It shows:
Section drawings are used to clear up something that might not have been shown clearly on the plan.
Detail drawings are used when an aspect of a drawing is too small to be sufficient. They are drawn to a larger scale.
Structural drawings are included to provide the requirements for the structural elements, such as:
Plumbing, mechanical, and electrical plans are also included. It is important to be familiar with each section of the blueprints so you can successfully coordinate with those who are also working on the structure.
Pages 5.11 and 5.12 of the textbook show 14 steps to reading blueprints successfully. They are:
Don't forget to do the discussion group question!
 |
 |
 |
 |