Methods of Framing Houses
There are many methods of constructing a wood frame home. Many of these variations depend on economic conditions, availability of material, or the region's climate.
Structures (above the foundation) that are framed and constructed entirely of wood fall into several classifications:
1. Platform frame
2. Braced frame
3. Balloon frame
4. Post-and-beam frame
A) Platform Frame
In platform framing a floor box and joists making up the platform is built and placed on a supporting understructure (sill plates, headers, or beams) where it sits flat and gets fastened down against wind lifting, with galvanized metal tie straps.
Once the boxed floor platform is squared, leveled and fastened then the subfloor, walls, ceilings, and roof are built onto and above that initial platform. This can be repeated floor by floor, without the slowdowns and dangers of fastening and leveling rough-sawn joists of a new floor together to the walls from ladders extending one or even two stories up.
Generally, the flooring ('platform') is constructed, then the walls built on top of that layer, then another atop that, and so forth, making for quick efficient labor-saving construction methodologies.
Technological advancements like the development of joist hangers have further sped up and enhanced the process of building platform frames.
Even skyscrapers use a modified form of platform framing technique (and the same tools and technologies) once construction builds the initial structural skeleton. Once the platform floor is laid down, the builder's crew can with chalk line, rule and pencil directly transfer an outline of the exterior and interior walls, their openings and relative locations with ease and precision from the plans or builder's blueprints.
A) Braced Frame
A braced frame is a structural system which is designed primarily to resist wind and earthquake forces.
Members in a braced frame are designed to work in tension and compression, similar to a truss.
Features of Braced Frames:
• Braced frames are almost always composed of steel members.
• Most braced frames are concentric. (This means that, where the members intersect at a node, the centroid of each member passes through the same point.)
• Some braces are intentionally designed to accommodate eccentricity in the connections. These frames are called Eccentrically Braced Frames. Because EBFs are highly ductile, they are permitted in areas of high seismic hazard.
C) Balloon Frame
Balloon framing—also known as "Chicago construction" in the 19th century— is a method of wood construction used primarily in Scandinavia, Canada and the United States (up until the mid-1950s).
Once popular when long lumber was plentiful, balloon framing has been largely replaced by platform framing.
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It utilizes long continuous framing members (studs) that run from the sill plate to the top plate, with intermediate floor structures let into and nailed to them.
The heights of window sills, headers and next floor height would be marked out on the studs with a story pole.
D) Post and Beam Framing
It is the method of creating structures using heavy squared off and carefully fitted and joined timbers with joints secured by large wooden pegs (larger versions of the mortise and tenon joints in furniture).
Post and beam framing is commonplace in large barns.
The methodology comes from making things out of logs and tree trunks without modern high-tech saws to cut lumber from the starting material stock.
Using axes, adzes and draw knives, hand powered auger drill bits (bit and brace), and laborious woodworking, artisans or farmers could gradually assemble a building capable of bearing heavy weight without excessive use of interior space given over to vertical support posts.