Framing exterior walls of a home happens immediately after the floor is framed. Building codes require that exterior walls be sheated with plywood or oriented strand board, OSB. Walls in cooler climates are built with 2x6 framing and in warmer climates they are built with 2x4 framing. The most common layout for wall studs is 16 inches on center.
Framing exterior walls is different from interior walls. Exterior walls provide strength and rigidness to a home so they need to be anchored down with anchor bolts and sheeted with plywood or O.S.B. (Oriented Strand Board).brief how to
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The first step in building exterior walls is to mark the wall location on the floor with a chalk line. Make sure the plate will be at the edge of the concrete or framed floor so the sheeting on the wall will go over the edge. Measure back from the edge 3 1/2 inches for 2x4 walls and 5 1/2 inches for 2x6 walls. Put a mark at each end of the wall. Snap a chalk line between the two marks.
After the wall is located then the top and bottom plate are cut to length and put on the wall line mark. The plates are then laid out and marked with all the walls, doors, windows and other items in the wall. Try to cut top and bottom plate from single pieces of lumber but if the wall is longer than your top and bottom plates then place the joint on the center of a stud.
Crowning: The plates are now seperated and the wall studs are put between them. Make sure that the bow in all of the studs is curving up, this is called "crowning the studs".
Nailing: After all the framing members are installed and nailed off, 3 nails in each end of each stud for 2x6 walls and 2 nails in each end of each stud for 2x4 walls. Line the stud up with the mark on the plate, making sure it is on the correct side of the mark and nail the plate to the stud.
Nailing Order: Nail on the windows or doors headers first if there are any. It is easier to nail on trimmers and headers before the adjacent studs are installed because you need to nail on the side of the king stud into the header and trimmer and it is easier to do that if there is not a stud in the way.
Square The Wall: After the wall is nailed together it needs to be made square. Put the bottom plate of the wall on the exterior wall chalk line and toe nail the bottom plate to the floor, this keeps it straight while the wall is squared. With only the bottom plate nailed to the floor use your tape measure to measure diagonally from top corner to bottom corners across the wall. Move the top plate of the wall back and forth until the dimension is exactly the same going both ways, this tells you the wall is square.
Put a nail thru the top plate into the floor to hold it. Double check that the wall is square because once the sheeting is put on it will be impossible to change its squareness. Read the article How To Square A Wall for detailed information
Layout: Exterior walls are covered or "sheeted" with Oriented Strand Board, OSB, or Plywood to give them strength. Start by lay a piece of sheeting on the wall at the end you laid out the wall studs from. The edge of the sheeting should break exactly on the center of a wall stud. If you are framing on a wood floor with joists you will need to extend the sheeting so that it extends down to the sill plate on top of the foundation. If you are framing on a concrete slab make sure the sheeting does not extend past the sole plate because that would lift the wall off the floor when it is stood up. On wood framed walls built over floor joists this means that the OSB panel will not extend up the wall to the top plate. A block of wood will need to be installed at the joint between the upper and lower sheeting panel after the wall is stood up.
Nailing: Nailing of exterior wall sheeting is very important. It needs to be done according to building code standards or a structural engineers calculations. The requirements will tell you how many nails need to be put in. Make sure that the nail heads are flush with the surface and do not break the face of the osb. Check with your local building department to see what is required for your project.
Cutting the window or door openings is easiest to do as you go along and sheet so that you can see a part of the window or door opening and measure and mark it before it is totally covered up.
Once the OSB is nailed on the wall panel becomes very rigid and is ready to be stood up. The wall is stood up and nailed onto the floor in line with the chalk line. It must also be braced with long 2x4 members
Install the blocking board behind the joint on the wall where the upper and lower sheeting panels meet.
To straighten a wall you will use a string line tied between two nails, one on each end of the wall at the tops of the wall. Put the nails in and leave the heads off the face of the wall about 1 inch. Tie the string line at 1/2" off the face of the sheeting and pull it tight enough so that it does not sag. Straighten the top of the wall so that it is 1/2" off the string line all the way along it. Use a 16' 2x4 nailed to the top of the wall and the floor to hold the wall in place once it is straight. These braces must be left in place until after the roof trusses are installed so the walls stay straight.
The double top plate strenthens the exterior walls to help them hold the load of the roof trusses and keep them straight. Joints in double top plates must overlap by 24 inches or more if you are using the IRC and overlap by 48" or more if you are using the IBC. There are two ways to install the double top plate, before or after the wall is raised.
Plating Before Raising: Some framers install the double top plate when the exterior wall is on the ground and then use a circular saw to cut out the plate after the interior walls are built. This makes the wall stronger when lifting it.
Plating After Raising: The walls can also be top plated after they are stood and the interior walls are built.
After the walls are straightened and braced and the top plates are nailed off you are ready to build the interior walls. Read the article How To Frame Interior Walls to learn about framing interior walls.
There are two basic ways to frame a wall, on the ground and stand it up or build it in place. This article teaches you how to build a wall on the ground and then stand it up. If you are building a wall in place, like for a basement wall, see the article called basement framing.
Measure the length of the new wall and cut two 2x4's for interior walls and/or 2x6's for exterior walls or interior plumbing walls to the length of the new wall. If you are building the wall on concrete you will need to use one treated board and one regular board. If the wall is on a wood floor you can use two regular boards of douglas fir.
Crown the boards: Now stand the two plates on their edge and look down them, most boards have a "crown" or bow in them, place this bow upward on both boards. Put the boards next to each other and make sure the ends are flush with each other.
Layout stud locations by hooking the tape measure on the end of the plates and marking every 16 or 24 inches depending on your preference. To make sure the studs are 16 or 24 inches "on center" you will need to hold back the mark half of the width of a 2x4 which is 1 1/2" wide so you will hold back 3/4" on each mark, ie. mark at 15 1/4", 31 1/4"....etc.
If this is confusing you can mark the first stud location on the plates at 1 1/2" in from the end and then put a nail on that line, hook your tape measure on that nail head and pull layout down the plates. Now when you measure 16" or 24" o.c. you will mark it directly on the 16" or 24" mark. Make sure to mark an X on the correct side of the inch mark so the stud gets nailed in the proper location.
Lay the studs next to the marks on the plates and crown them. If the studs have been crowned the finished wall will have an imperceptable curve instead of an in and out wave.
Hold the stud up against the plate so that the edges that are closest to you are flush with each other. Nail the studs to the plates on their marks. Use _______ nails. Use two nails for a 2x4 wall and three nails for a 2x6 wall. Make sure that the studs are naile on the proper side of the marks you made earlier.
safety tip: The main safety concern here is making sure that the hand that is not holding the nail gun is far enough away from the gun that a nail cannot go thru a board and hurt the hand that is holding the board. Also, you will want to wear safety glasses whether you are using a nail gun or hammering.
Stand the wall up and put it on the proper side of the line on the floor. Put one nail between each stud thru the plate into the floor. If you are installing the wall on concrete you will need to use powder actuated shots to nail the bottom plate to the concrete.
Each of the parts of a framed wall are shown in the above graphic. Keep reading to learn more about each part of a framed wall.
Description Of The Parts Of A Wood Framed Wall Bottom Plate or Sole Plate
The bottom plate of the wall sits on the floor. It can sit on wood sub flooring or on concrete. The methods of attachment to the floor are determined by the flooring type and the location of the wall
Wall studs are typically 2x4 or 2x6 boards that are set at 16 inches on center. 24 inches on center is often used to frame basement walls that are non bearing. The size of the wall stud being used is determined by:
2x4 Wall Studs
- Interior walls in most parts of a home or structure
- Exterior walls when allowed by local codes and structural engineering calculations.
2x6 Wall Studs
- Exterior walls are often used to frame the exterior walls to increase the R-value of the walls. This increases the ability of the the structure to comply with the MEC, model energy code. It also allows the occupants of the structure to better control heating and cooling costs.
- Interior Bearing walls at load bearing locations. This is usually specified by a structural engineer if it is required.
- Plumbing Drain walls that require a larger cavity to run pipes through.
Headers are used to increase the size of an opening in wall framing. The size of the header depends on the span of the opening and the loads that bear on the wall above the header. The material used to build headers depends on the load capacity needed. Headers are supported on each end by a Trimmer.
Three types of headers are typically used in wood frame construction:
LVL Beams are Laminated Veneer Lumber. The benefits of using lvl headers are:
2x Boards Turned On Edge are used for light load bearing walls. A header is typically made by sandwiching a piece of O.S.B. between two 2x boards.
Glu Lam beams are similar to LVL beams and have similar characteristics. Check with your lumber supplier or structural engineer to see which one will work best for your application.
The trimmer is the board that holds up a header or beam. The trimmer is nailed to the king stud on each side of the beam ends. It is most common to have one trimmer on each end of a header but larger openings like garage doors require 2 or 3 trimmers on each end of the beam. The number of trimmers on each end of the beam is determined by the engineering that describes the load bearing capacity of the trimmer.
A cripple is the term used to describe a shorter board that fills in the wall framing above or below an opening in a framed wall such as a door or window. They use the same size lumber as the wall is framed with. They are installed using the same layout spacing that is used for the full sized studs in the wall.
The king stud goes from the bottom plate to the top plate. One king stud is installed on each end of the header and is nailed directly to the ends of the header. The tops and bottoms of the king stud are nailed to the wall top and bottom plates. Use the same wall studs that are used to frame the rest of the wall for king studs.Sill
The sill is installed when framing a window opening. The sill is typically installed after the trimmers are installed so they do not interfere with the load path of the trimmers holding up the header. The sill is held up by the cripples below it. Use the same lumber used to frame the wall.related articles
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