Understanding Framing Terminology:
Don’t Get Lost in Language
lmost every remodels and new construction is going to involve new framing. Larger repairs are going to involve framing as well when it comes to rot and decay. So in these circumstances, you’ll want to understand what the contractor is saying to you. Of course, the first step to communication is the understanding of language, hence, framing terminology.
In this article, we’ll equip you with what all those pieces are called and what their basic functions are.
We’ll begin at the home’s foundation and work our way up to the roof.
Foundation
Masons will either build brick and block walls or pour concrete for the foundations.
This gives us a flat-level base to build off of.
Mud Sill Or Sill
The first piece of framing installed is what’s known as the Mud Sill or just Sill. This piece provides a stable layer for all the framing above it. if untreated wood sits on masonry, it can rot because masonry always contains moisture. Mud Sill is made of treated lumber, so it doesn’t rot and acts as a barrier between the masonry and the wood framing above it. The Mud Sill runs the entire perimeter of the foundation and is generally always attached with anchor bolts. Anchor bolts prevent the house from shifting upwards in strong winds.
Joists
Joists are the floor structure of the house. They’re long pieces of lumber, typically in sizes of 2×8, 2×10, or 2×12. These are turned on their edges and supported at various points from beneath. Joists span over exceptionally large spaces. These joists give us something to walk across such as floors and hold the weight above us in ceilings. Joists at one time were just a typical dimensional type of lumber (2×8, 2×10, 2×12). More recently, engineered lumber has nearly taken place of these types of joists and replaced them with I Joists.
I Joists
I Joists are just like I Beams with the exception that I Joists are made from OSB lumber. OSB lumber is considered a much greener building because it’s made from smaller trees. I Joists can also have pre-cut knockouts that you can run various utilities through such as wiring, gas, and water. In essence, I Joists not only saves the planet but makes construction costs cheaper and simpler.
Rim Joist
The piece of framing that wraps around the floor joists is what’s called the rim joists. The rim joist wraps around the entire perimeter of the floor framing. The other joists run into it, butting up against it.
Girder
Beams or girders can support joists. Girders and beams are horizontal framing pieces that are generally stronger and larger pieces of flat lumber. In residential construction, these girders and beams often come standard 9”x12” diameters.
Beams
Beams are often larger and sturdier pieces of lumber acting as a backbone for the joists to rest on- a sort of super joist, for other framing components. Sometimes you’ll see where joists can run directly into the beam and are held together by hardware like gang plates.
Both girders and beams are other examples of where OSB is becoming more common. OSB-engineered lumber allows for longer and stronger spans. There are certain conditions where both girders and beams may be grouped together giving it an unsurpassed strength of the span.
Masonry Piers, Columns, And Posts
These are typically any vertical support that the beams, girders, and rim joists are set on. A good example of these is the columns you might see holding up a wrap-around porch. Although they look decorative, they’re an integrative part of the structure that transfers the weight to the home’s foundation.
Subfloor
Once the floor structure has been framed, the joists begin to get covered with sheets of plywood or OSB. These sheets of lumber come in 4’x8’ sheets and will cover the entire surface to all edges of the perimeter. Everything will begin to be built upon these subfloors which brings us to studs and wall framing.
Studs And Wall Framing
Studs are what’s used for framing walls throughout the house. The standard sizes of lumber for studs are 2”x4”, and 2”x6” standing vertically on end similar to columns within the home. These wall studs will be found 16” on center or sometimes 24” on center. Studs fastened together are stud packs and act as makeshift columns and posts within the wall that helps transfer the weight to safer points below.
Plate
Although wall studs stand vertically, they never really touch the floor. They sit upon another 2”x4” or 2”x6” that lays horizontally beneath, which is known as a plate. Similar to that of the mud sill that was discussed earlier. There’s no need for the plate to be treated, though, since moisture from the subfloor is nonexistent.
Framing the studs together like this makes it easier for walls to be raised once constructed. The tops of these wall frames will get “double plated” for strength and durability and are known simply as the “top plate”.
Headers
Studs and plates run continuously throughout the house’s walls uninterrupted until it reaches a door or window opening. Above doorways, entryways, windows, and garages you’ll see this type of framing. It’s an important part of the structure and key to transferring weight over the opening and down either side of the opening.
Jack Studs, Trimmer Studs, King Studs
The ends of the headers rest on what’s known as jack studs or trimmer studs. They’re then enclosed by taller vertical lumber called king studs that extend from plate to plate. The empty spaces over these headers are then filled with shorter studs to fill in the empty space. These smaller studs are primarily used to create a nailing surface for drywall.
Rough Opening Rough Sill
The entire framed opening of a window or door is known as a rough opening, and the bottom horizontal piece in the window opening is a rough sill. All of these openings are framed in a specific way to transfer the weight away from the openings of the windows and doors.
Noggin Blocking
Smaller horizontal pieces of 2”x4” or 2”x6” lumber within the wall frame are known as noggin blocks. These blocks serve the purpose of both fire prevention and walls from warping. Regarding fire prevention, the noggin blocks slow down the rate at which the fire can progress. Preventing the flames from jumping from floor to floor like a chimney flu. Temperature change often makes lumber twist and bow. Using noggin blocks ties the studs together to shorten the vertical span, making them less susceptible to warping.
Staircases And Stringers
Stringers are primarily what you would see outdoors. They’re notched from pieces of lumber that support the treads and risers and are exposed on either side. Interior stairways are generally manufactured as a single enclosed unit at the factory. They’re built according to specs from the contractor and ready for installation upon arrival.
Rafters
Rafters are similar to joists with the exception that they sit diagonally at a fixed pitch. Rafters can sometimes rest on the top plate of the wall below it. Other times they may rest on the floor structure of an attic. Rafters, as they continue their pitch upwards, meet in the center known as the ridge board.
Roof Trusses
Roof trusses are pre-assembled and create the structure and shape of the roof.
They are installed side by side, held together like rafters until the sheathing is attached.
They’re made of shorter and smaller pieces of lumber and held together with what’s known as a truss connector plate or gang plate. Once the trusses are covered with sheathing, they become similar to a girder as they span from wall to wall.
Sheathing
The sheathing is a layer of plywood that acts like a skin to the home. The home may have all of its bones, but what keeps everything in place from shifting and moving is the plywood sheathing. Exterior sheathing can come in lengths such as 8’, 10’, and even 12’ but most are always 4’ in width. Exterior sheathing, roof, and walls are commonly ½” thick and made of OSB.
From top to bottom, there are a lot of different components that make up framing. Understanding terminology within home building and remodeling is valuable and key to knowing what’s going on and ways to help you plan.