Basement Framing

How To Frame A Basement

framing basement walls

Finishing your unfinished basement is by far the least expensive way to add liveable square footage to your home. Framing the walls, ceilings and the miscelaneous nooks is the first step in a basement finish project (Unless you need to add a plumbing drain or sump pump in the floor or are cutting the concrete walls to add windows or a doorway). Keep reading to learn how to frame all the areas of your basement. Finishing a basement is a big project but if it is tackled one part at a time it is very manageable.

 

brief how to

In this article, you will find information about:

  1. Design The Basement Floor Plan

  2. Do A Material Take Off

  3. Install Blocking In Joists

  4. Layout The Basement Wall Locations

  5. Layout Windows and Doors On The Exterior Walls

  6. Layout The Interior Walls

  7. Framing The Top And Bottom Plates

  8. Framing Around The Windows

  9. Install The Studs

  10. Framing Around Obstructions

  11. Install Miscelanous Blocking

tools and materials

  • Hammer
  • Nails
  • Framing square
  • 4 foot level
  • Chalk line
  • Construction Pencil
  • Circular Saw
  • Tape measure
  • Hammer drill and Tapcon screws or a powder actuated fastener (use the 2 1/2" drive pins with the yellow shots).
  • A straight 2x4 long enough to reach from the floor to just above the bottom of the floor joists, you can tape or hold the level on the edge of the 2x4 to transfer marks from the floor to the ceiling accurately. This article refers to this tool as the "2x4 and level"
  • Specialty tools that make the job much easier: Nail gun with 12d nails, screwgun and 3" grabbers.

step 1 Design The Basement Floor Plan

basement finish plans

Before framing the basement you will need to make sure your floor plan will work. It helps to draw up a floor plan to see how the floor plan will work before spending time and money building.

Permit: Designing the basement and creating a good to scale drawing of your design is essential to a good finished product. It is much easier to erase a mistake on paper than to build it twice in the basement. Applying for a building permit on basements is usually easy and inexpensive in most states and well worth the effort because the inspector will be able to answer many questions and help to point out mistakes before they are covered by sheetrock.

Plans: Most building departments will accept very rudamentary plans as long as they are to scale. They will often give you an example that you can take home and mimic. The plans will need to show the walls, doors, windows, plumbing fixtures, cabinets, lights and outlets and notes telling of the finishes like carpet, tile, paint etc. If it is too much of a project to draw the plan yourself then the next cost effective option is to hire a drafter and if you want more skill you may hire the services of an architect.

Engineering: If you plan to put an opening thru a existing basement wall that holds up the floor above you should have a structural engineer size a beam to hold it up. This is very common and usually not that expensive if you shop around. The engineer will probably come to your house and determine the loads on the wall. They will provide you with a few sheets of calculations for the building department and a sheet that describes the beam size and how the beam should be held up. This type of service often falls into the "minimum charge" catagory, around $100.

stud wall nomenclature

step 2 Do A Material Take Off

To get the best pricing it is best to buy your lumber in bulk. You don't need to be exact but it helps to have a count of the different types of lumber that is close, especially if you are paying for delivery.

Order wall studs: To count the studs you can add up the lineal feet of walls and order a stud for every foot of wall, The actual layout of studs for basement walls is usually 24" o.c. because they are not structural, but by the time you add corners and blocking and other items it will be fairly close to what you need.

Order Plate Material: To count the top and bottom plates for the walls, figure the total lineal feet of the walls, divide it by 16' and round up. Order this number in douglas fir for the top plate at the tops of the walls and then order the same amount of treated lumber for the wood touching the concrete because any wood touching the concrete will need to be treated.

  • Order two extra 2x4x16's doug fir for each window you are framing
  • Order a 2x4x16' for each doorway you are framing
  • Order any beams or 2x6's for headers if you are putting openings thru existing bearing walls.
  • 1/2" OSB sheeting for drops around ducting, window sills, fire blocking
  • Anchor bolts to anchor the bottom plate to the floor. Check with your local building dept for sizing.

step 3 Install Blocking In Joists

When a basement wall runs parallel to the floor joists above you will need to install blocking between the floor joists so the top plate can be attached. Having the blocking installed before the next step will help in laying out and framing the walls. (This image shows 5/8" O.S.B. on top of the top plate, it goes all the way to the concrete to act as a fireblock between the wall and the concrete.)

basement wall framing joist blocking

basement framing nomenclature

step 4 Layout The Basement Wall Locations

Layout the perimeter walls first and then do the interior walls.

Check The Concrete Walls For Plumb: Using the level walk around the perimeter walls and see how plumb, (straight up and down they are). If there are any that are out of plumb you may need to compensate for it in your layout of the perimeter walls by bringing the wall farther into the room so the framed wall is not crooked like the concrete wall.

Mark The Perimeter Wall Locations: Using a tape measure and pencil, mark the floor at each end of each wall 4 to 4 1/2" from the wall, depending on the plumbness of the concrete wall. Use the chalk line to snap lines on the floor, this is the line you will build the walls to.

basement wall chalk line framing

Transfer The Lines On The Floor To The Ceiling: Using the 2x4 and level, transfer the wall line marks on the perimeter concrete floor to the bottom of the joists or blocks above. Mark a chalk line on the bottom side of the floor joists. This line, combined with the line on the floor represents the front of your new wall.

step 5 Layout Windows and Doors On The Exterior Walls

Use the level to draw a plumb line on the wall directly in line with the outside of the window frame, (not the concrete corner). This line represents the back side of the drywall and the front side of the stud holding it. Tip: you want the drywall to butt up to the window about 1/4" to 1/2" from the edge of the frame as shown in the picture. If the existing opening around the window is farther back than the 1/4" to 1/2" from the frame you will need to install framing behind it. The easiest way to do this against concrete window openings is to glue OSB to the concrete with construction adhesive. see the drawing.

step 6 Layout The Interior Walls

layout basment wall framing

Locate the interior walls by measuring in from your perimeter lines and existing bearing walls according to your plans. Use the chalk line to mark the wall lines. It is easiest to mark both sides of each wall to keep the locations of the walls straight in your mind..

Cut the top and bottom plates to length for the perimeter walls, remember the top plate is doug fir and the bottom plate is treated lumber. 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. Put the plates on the line where the wall will be and then layout any window, door and wall locations. Then layout the rest of the studs for the wall.

wall framing layout on plates

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.

step 7 Install The Top And Bottom Plates

Put the treated plate on the line on the floor, make sure that the stud locations are facing the room so you can see them to frame the wall. Using the hammer drill or a powder actuated nail gun, fasten the bottom plate to the concrete floor. Install an anchor 8" from the end and then at 32" o.c. along the plate. (Note: Check with your local building offical to verify if it is ok to use 5/8" or thicker O.S.B. as fireblocking at the top of the perimeter walls. If it is you can install a piece of 5/8" O.S.B. fireblocking along the top of wall line BEFORE installing the top plate of the wall. You can view an example of this in our fireblocking tutorial.)

To install the upper plate find the straightest 2x4x16 you can and cut it so it can touch the side of a floor joist while resting on the concrete floor. Put the cut 2x4 on the side of the bottom plate, hold the level on the edge of it and make it plumb. Mark the joist or blocks at each end of the top plate. Repeat this at both ends and then snap a chalk line between the marks. Raise the top plate up to the line with the marks facing the room, matching the bottom plate, make sure the marks are directly above the marks on the bottom plates then nail the top plate to the joist.

Top Plate

step 8 Frame Around The Windows

After the top and bottom plates are installed you will frame around the windows first. It is easiest to frame around the windows first before the wall studs are in the way. Using the marks that you transfered to the plates from the windows, install the framing in the following order:

  1. Install the king studs first.
  2. Then install the trimmers
  3. Then header
  4. Then the sill
  5. Lastly the cripples.

Tip: Make sure to nail the boards on the correct side of the marks on the plates.

frame basement window

Tip: Remember you want the drywall that is installed perpendicular to the window to butt up to the window frame about 1/4 to 1/2" in from the outside edge of the window frame, so you need to adjust the framing accordingly.

step 9 Install The Wall Studs

Frame the rest of the wall. Measure, cut and install the studs for the ends of the wall first then do the windows or doors, and finally, install the rest of the studs. You will measure each stud individually, cut each stud, and install it in its respective space. It is important to measure each stud individually because basement concrete floors are not perfectly flat which makes the length of the studs different from each other.

step 10 Framing Around Obstructions

This will describe ceiling duct furring out. The techniques can be used in many basement framing areas.

Ductwork: To hang drywall around duct work on the basement ceiling and other obstructions it is helpful to have framing to screw the drywall to. Start by using a 2x2 and nailing it perpendicular to the floor joists along the side of the duct. Every situation is different but most often it is desireable to be within 2 inches of the duct to minimize the impact of the framing on the room. Measure down from the bottom of the joist to the ducts lowest point. Cut strips of the OSB board to this dimension and the length to the length of the duct. Nail or staple this OSB board to the side of the 2x2 so it hangs from the ceiling. Nail another 2x2 to the bottom edge of the OSB on the same side as the upper 2x2. Ducts are often run parallel to a wall, (as shown below), when this happens you may install a 2x2 or 2x4 along the wall studs. Then install a piece of O.S.B. horizontally. Make sure the bottom is level with the bottom of the furring drop on the other side of the duct as shown in the drawing.

ductFurring

Fire Blocking: When framing against a basement wall as shown you will need to install fire blocking between the wall studs. The idea is to stop fire from coming up the wall and into the cavity that the duct is in. See the Fire Blocking article.

Plumbing on walls: Drains sometimes run down basement walls and need to be furred around. The two ways to deal with this are to either bring the whole wall out in front of the pipe or to frame a bump in the wall.

Plumbing on ceilings: The plumbing can be covered the same way you frame around duct work, shown above, often all the plumbing will be run adjacent to mechanical. If you have water lines running across the bottom of floor joists you can simply attach 2x4, or larger lumber to the bottom of the joist on each side of the pipe.

step 11 Framing Miscelanous Blocking

Blocking Tip: When installing blocking or sheetrock backing, make sure the blocking is on the same plane, or flush with, the wall, (you can use the 4' level to check this)

Corners: When two walls meet at the corner there is always an extra stud that needs to be put in to nail the sheetrock on one of the walls. Use a 2x4's or 2x6's as shown here.

framing corner basement

Framing Basement Wall Ends: There are several ways to frame the junction of two walls. You can use any of the framing methods shown here but it is recommended that you do not use number 4 because you cannot insulate behind it.

framing corner backing

Wall tops: The tops of walls often have areas where the ceiling sheetrock needs a backer to screw it to. This happens on inside and outside corners.

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