Structural Systems

Wood Platform Dustin Winter & Eric Okerstrom Balloon Framing ¤ Balloon framing was invented in the U.S. in the mid-nineteenth century and consisted of elements with small cross-sections (what we now call "dimension ") configured in the wall as plates (horizontal) and studs (vertical); and in the floors and roofs and and respectively. This method starts with studs running from bottom to top and then the floors are added at desired height. There are a few advantages and disadvantages to Balloon Framing. Platform Framing

¤ Platform framing: A subsequent modification of balloon framing was so-called "platform framing," which is the prevalent mode of light wood framing today. The main difference between the two systems is that in balloon framing, the vertical studs are continuous from foundation to roof, whereas in platform framing, the studs are interrupted at each floor level by the floor construction. Types of Framing

Balloon Platform

Advantages of Platform framing

¤ Studs are only one story high, so long pieces of lumber are not required;

¤ Wall sections can be fabricated on the floor platforms in a horizontal position, and then lifted in place (see top photo)

¤ It is a much simpler process of construction compared to balloon construction. It first starts with the foundation with those walls constructed while the first level is placed in as a platform and then the walls are places for that level and so on from there. This method used less wood, smaller piece, creates a natural fire barrier, requires less labor to build. (see bottom photo) Disadvantages of Platform framing ¤ Because the vertical studs are interrupted by headers and joists whose orientation places them perpendicular to the direction of load at the lines of vertical structure, there may be more shrinkage at those sections, potentially causing problems with rigid siding materials such as brick veneer.

¤ Structural problems may occur after building is completed. This can happen from the joists and headers vertically shrinking when the wood dries. Also cause siding materials will need more up keep. Platform Framing Platform Framing Advantages of Balloon Framing

¤ Once completed few problems will come up, adds durability to the building, having a super flexibility window design, and is stronger in highs winds.

¤ Greater strength to resist high wind loads.

Common Uses 1. In a great room or two story foyer.

2. To build a tall chimney.

3. In a room where a cathedral or vaulted ceiling is located. Disadvantages of Balloon Framing

¤ A fire can spread from floor to floor quickly, with walls the length of the building they can become very heavy and hard to put in place.

¤ Longer framing member's are required and the cost per lineal foot is more than standard pre cut framing stud's.

¤ The top plates of balloon framed walls are often 17 feet or more above the working platform. This height requires scaffolding for tradesmen. Not only in the framing phase, but in all phases to follow. & Post/Beam Construction

¤ Timber Framing and “post-and-beam” ¤ Advantages: fast building time, minimal labor, construction – this method of using recyclable, low volume of waste on site, 60+ heavy timbers besides typical life span. dimensional lumber. These timbers are large squared-off that are held together by oversized wooden pegs. The ¤ Disadvantages: lack of skill among builders, majority of buildings in the 19th century more design and engineering time before where built this way and many of them hand, inside exposure to weather before are stay standing today. enclosed.

References

¤ http://www.carpentry-pro-framer.com/balloon-framing.html

¤ http://www.doityourself.com/stry/platform-framing-vs- balloon-framing#b

¤ http://www.environ.ie/en/Publications/ DevelopmentandHousing/BuildingStandards/FileDownLoad, 1677,en.pdf

¤ https://courses.cit.cornell.edu/arch264/notes/wood- systems.html