How to Install a Prehung Interior Door

How to Install a Prehung Interior Door

Installing an interior prehung door is an easy upgrade that can dramatically improve the appearance of your home. this process comes after the framing work is complete and the drywall has been installed.

If the rough opening for the door has been framed accurately, installing the door takes about an hour. so, what size prehung door do I need? and how to install it?

I can say that Standard prehung doors have 4½-inch-wide jambs and are sized to fit walls with 2 × 4 construction and ½-inch wallboard. If you have 2 × 6 construction or thicker wall surface material, you can special order a door to match, or you can add jamb extensions to a standard-sized door.

To Install the door, first, I will Determine if a prehung door is right for my situation. Familiarize me with the necessary parts. I have to Determine if the floor is level where the door will be hung. and Make sure the rough opening is plumb. and I need to Shim the trimmers and Fit the door into the opening. Now I will mount the hardware, Adjust the reveal. Anchor the jamb. Replace the hinge screw. Attach the split jamb. Mount the latch hardware.

About Doors


Exterior doors function in numerous ways:

  1. They let people in and out. This is not as trivial as it may seem but relates to the design of a welcoming entryway—an architectural subject by itself.
  2. They let large objects in and out. The minimum width for an entry door (and some interior doors as well) should be 3 feet to facilitate moving furniture and appliances.
  3. They keep intruders out. All entrance doors should have quality dead-bolt locks as well as the common latch set. In urban areas, an additional lock, operated only from the inside, would be worthwhile.
  4. They keep out winter wind and cold. Except for custom doors intended for historic preservation, the great majority of exterior doors sold today are steel with foam-insulated cores. These represent a giant advance over the classic wood door, in thermal performance if not appearance.
  5. Compared with an R-value of 1.5 for the classic wood-paneled door, the foam core door has an R-value of 6 to 12, reducing conductive heat loss by 75 to 85 percent. The best metal doors also incorporate magnetic weatherstrips, virtually eliminating infiltration.
  6. They let in summer breezes, winter solar gain, and natural daylight. The original function of the storm door was the same as the storm window: to reduce winter heat loss by conduction and infiltration. These losses have largely been eliminated by the steel door. However, a combination “storm” door may still be desirable for summer ventilation.


When ordering a prehung door, you must specify its “handedness.” The illustration below shows how handedness is defined. If a door opens toward you and the doorknob is on your left, the door is left-handed. If a door opens toward you and the doorknob is on your right, the door is right-handed.


The illustration of the images shows how the five most common types of doors are constructed. Fiberglass and steel doors are commonly used as entrance doors because of high R-value and dimensional stability. Wood panel doors are used primarily on the interior of classic-styled homes. The hollow-core door is used exclusively on the interior of low-end homes, whereas the more substantial solid-core door is common in modern, high-end homes.

How Doors Are Constructed

Framing The Openings of The Doors

Creating an opening for a door in a wall involves building a framework about 1 inch wider and ½ inch taller than the door’s jamb frame. This oversized opening called a rough opening, will enable you to position the door easily and shim it plumb and level.

Before framing a door, it’s always a good idea to buy the door and refer to the manufacturer’s recommendations for rough opening size.

Doorframes consist of a pair of full-length king studs and two shorter jack studs that support the header above the door. A header provides an attachment point for wallboard and door casings.

On load-bearing walls, it also helps to transfer the building’s structural loads from above down into the wall framework and eventually the foundation.

Door framing requires flat, straight, and dry framing lumber, so choose your king, jack, and header pieces carefully. Sight down the edges and ends to look for warpage, and cut off the ends of pieces with splits.

Tools & Materials

  • Tape measure
  • Framing square
  • Hammer or nail gun
  • Handsaw or reciprocating saw
  • Framing lumber
  • 10d or pneumatic framing nails
  • 3⁄8″ plywood (for structural headers)
  • Construction adhesive
  • Eye and ear protection

How to Frame a Rough Opening For an Interior Prehung Door

Doorframes for prehung doors (left) start with king studs that attach to the top and bottom plates. Inside the king studs, jack studs support the header at the top of the opening. Cripple studs continue the wall-stud layout above the opening. In non-load-bearing walls, the header may be a 2 × 4 laid flat or a built-up header (below). The dimensions of the framed opening are referred to as the rough opening.


To mark the layout for the doorframe, measure the width of the door unit along the bottom. Add 1″ to this dimension to determine the width of the rough opening (the distance between the jack studs). This gives you a ½” gap on each side for adjusting the doorframe during installation. Mark the top and bottom plates for the jack and king studs.

How to Frame a Prehung Interior Door Opening (Load-Bearing)

  • Door framing on load-bearing walls will require a structural header that transfers loads above the wall into the jack studs, sole plate, and down into the house foundation. Build it by sandwiching a piece of ½” plywood between two 2 × 4s. Use construction adhesive and nails to fasten the header together.
  • Mark layout lines for the king and jack studs on the wall’s top and sole plates. Cut the king studs slightly longer than the distance between the wall plates, and toenail them in place with 10d nails or 3″ pneumatic nails.
  • Cut the jack studs to length (they should rest on the soleplate). The height of a jack stud for a standard interior door is 83½”, or ½” taller than the door. Nail the jack studs to the king studs.

  • Install the built-up header by resting it on the jack studs and end nailing through the king studs. Use 10d nails or 3″ pneumatic nails.
  • Fasten a cripple stud above the header halfway between the king studs for use as a nailing surface.
  • Cut a sole plate opening for the door with a reciprocating saw or handsaw. Trim the soleplate flush with the jack studs. Install the saw blade teeth-up for better access.


Variation: In a non-load-bearing wall, the header can be a piece of 2× framing lumber that lays flat on top of the jack studs. Cut it to length, and install by end nailing through the king studs or down into the jack studs. Toenail a cripple stud between the top plate and header, halfway between the king studs. It transfers structural loads into the header.

Tools & Materials for the Installation

  • Level
  • Hammer
  • Handsaw
  • Prehung interior door
  • Wood shims
  • 8d casing nails
  • Eye and ear protection

Tip: Jamb Extensions

If your walls are built with 2 × 6 studs, you’ll need to extend the jambs by attaching wood strips to the edges of the jamb after the door is installed. Use glue and 4d casing nails when attaching jamb extensions.

Steps to Install a Prehung Interior Door

To start, don’t remove shipping braces from the door, they keep the frame square. If the floor is not level, cut one leg of the frame. Prehung doors are built to allow for thick carpeting, so you may need to cut both legs if the bottom of the door is too high of an uncarpeted floor.

  • Center the unit in the opening, and check that the top is level.

  • Slide the door unit into the framed opening so the edges of the jambs are flush with the wall surface and the hinge-side jamb is plumb.
  • Insert pairs of wood shims driven from opposite directions into the gap between the framing members and the hinge-side jamb, spaced every 12″. Check the hinge-side jamb to make sure it is still plumb and does not bow.
  • Anchor the hinge-side jamb with 8d casing nails driven through the jamb and shims and into the jack stud.

  • Insert pairs of shims in the gap between the framing members and the latch-side jamb and top jamb, spaced every 12″. With the door closed, adjust the shims so the gap between the door edge and jamb is 1⁄8″ wide. Drive 8d casing nails through the jambs and shims, into the framing members.
  • Cut the shims flush with the wall surface, using a handsaw. Hold the saw vertically to prevent damage to the door jamb or wall. Finish the door and install the lockset as directed by the manufacturer.

  • When the door is correctly positioned, predrill and nail through the frame (and hidden shims) into the wall framing.
  • Also, drive finishing nails through the face of exterior molding into the wall framing. Set the heads, and fill with putty.
  • You can order most prehung doors with locks already installed or with the holes predrilled so you can install your own.
  • A lockset plus deadbolt provides extra security. Use long screws in the keepers that reach through to the house framing.
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How to Trim a Door

How to Trim a Door

Every work you have done or anyone did need to be finished. and Wood trimming, either painted or stained, is the finishing touch for your walls, windows, and doors.

In the next lines, I will show and teach you as much as I know, according to my experience and my researches about this title to add more value to this post, so, focus and keep reading until you get it.

Choosing Trim Materials


You can cut with a hand miter saw, but a power miter saw (a.k.a. chop saw) makes accurate, clean cuts with ease. Make some test cuts, and adjust the saw if it doesn’t make perfect 90° and 45° cuts. If cuts show some splintering, change the blade. Set the saw on a table, and set things up so you can easily rest trim boards flat on the saw’s base.

Things to consider when choosing trim materials:

  • If you will paint your trim, be aware that priming and painting can take longer than installation. Consider buying primed trim, which needs only a quick coat of finish paint.
  • Medium-density fiberboard (MDF) trim is an inexpensive option that resists denting. However, it will swell up if it gets even a little wet, so use it only where you expect things to stay dry.
  • You may be tempted to buy faux-finished trim boards that are very lightweight; they are made of polystyrene. I do not recommend this product, because it is easily dented, and even minor imperfections cannot be filled in attractively.
  • Unfinished softwood (usually pine) is a very common choice. It’s easy to work with and can be either primed and painted or stained. However, it is somewhat susceptible to denting, and if stained will not have the rich look of hardwood.
  • Oak or other hardwood will set you back in the bucks department. With a power miter saw and a power nailer, it is no more difficult to cut and install than the other types. It resists dents and is easily stained for a very handsome look.

Trimming a Door

Once a door is installed, the gap between jamb and wall needs to be covered with casing. Installing casing is pretty much the same for doors as for windows. Here, I show installing plain casing with backband, for mitered casing and casing with plinth blocks, see the post on trimming a window.

  1. The molding here is simple primed 1x4, rip-cut to a width of 27⁄8 in. so it will look less massive.
  2. You can also purchase “plain” casing. If you add backband as I do (steps 8 and 9), be sure it will match up with the casing’s thickness. Check the area around the door opening and scrape away any protrusions, so the casing can lie flat against the wall and jamb edge.
  3. If the jamb edge protrudes a bit past the wall surface, plane or sand it flush. Use a sliding square and pencil to draw a line all around the jamb edge showing the “reveal”-he portion of the jamb edge that will be exposed after the casing is installed.
  4. Measure the height of the side casing pieces-from the floor to the reveal line on the head jamb. Cut the side pieces and install them along the reveal lines-or so they just barely cover the lines. Start at the bottom and drive pairs of nails every 16 in. or so as you go up.
  5. You’ll probably need to bend the casing slightly to keep it aligned with the line. If you are driving hand nails, use small brad nails to drive into the jamb and 6d nails for attaching to the wall framing. If you have a power nailer, 2-in. finish nails work fine for both, but angle the nails slightly back when driving into the jamb, so the nails don’t poke through the face of the jamb. Measure across the side casing pieces for the size of the head casing.
  6. Hold the top casing in place; if it angles outward, you may need to slice the drywall paper around the outline and tap the wall in with a hammer and flat tool.
  7. Install the head casing with nails driven into the casing and the framing, and at an angle through the side casing.
  8. Measure for cutting the backband, mark the inside where it will meet the corners of the plain casing, and cut at a 45° bevel.
  9. Hold the backband pieces so they form tight miter joints and drive small finish nails to attach to the plain casing.


1-Rip-cut 1-by lumber or purchase plain casing.


2-Scrape away any protrusions on the wall or jamb.
3-Mark the reveal on the jamb edges.
4-Cut side casing to height and install with pairs of nails along the reveal line


5-5Measure and cut the head casing.


6a-If the wall is angled, cut through the paper around where the casing will go . . .
6b-…. then tap the wall in.


7a-Attach the head casing with nails driven into the jamb and framing . . .
7b-…. and through the side casing.


8-Mark the backband with the cutline where it will meet the corner and cut at a 45° bevel.
9-Attach the backband with small nails.

Answering Related Questions

How do you sand the bottom of a door?

  1. To sand the bottom of a door without removing it put the sandpaper on the floor, grit side up, and pull the door back and forth across it. Planing is usually the last resort since it will mean touching up the planed area with a sealer or finish to match the door. A rasp-type plane will often do the best job.
  2. If the condition has developed over time, you’ll be able to attempt alteration all of the screws on the hinges. If any of the screws turn within the wood without alteration up, then you’ll replace them with longer screws that grip the stud behind the frame and pull the door above your floor.
  3. move the door and hinges upon the frame, or leave the hinges within the frame and move the door up. Since most interior doors are hollow, readjusting the door within the frame should not be too tough.

Can I use a jigsaw to trim a door?

I Use a jigsaw and/or a circular saw to trim the new door to size.and will probably find that the bottom of the door needs to be trimmed to the correct height and you can use a jigsaw or circular saw to do this too.

Use a circular saw or a hand saw, a jigsaw is far from ideal for long straight cuts.
The first door you cut will indicate if you have enough timber in the base. If you cut out the timber with the cut then you will need to reinstate that timber to the base of the door.
Safer to take a few mm off top and bottom and rehang the door, but will require a plane.

Should baseboards match door trim?

The classic method is to use white for ceiling and trim (baseboards and window and door casings), and then paint the wall color or hang wallpaper. or, especially for hardwood baseboards that match the floor: staining or finishing them in the same color as the floor. always it’s your choice.

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Trimming Basement Windows

Trimming Basement Windows

Basement windows bring much-needed sunlight into dark areas, but even in finished basements they often get ignored on the trim front. This is partly because most basement foundation walls are at least 8″ thick, and often a lot thicker.

Add a furred-out wall and the window starts to look more like a tunnel with a pane of glass at the end. But with some well designed and well-executed trim carpentry, you can turn the depth disadvantage into a positive.

today I will explain and simplify the way to trim your basement windows, so, keep reading and focus.

A basement window opening may be finished with wallboard, but the easiest way to trim one is by making extra-wide custom jambs that extend from the inside face of the window frame to the interior wall surface.

Because of the extra width, plywood stock is a good choice for the custom jambs. The project shown here is created with veneer-core plywood with an oak veneer surface. The jamb members are fastened together into a nice square frame using rabbet joints at the corner.

The frame is scribed and installed as a single unit and then trimmed out with oak casing. The casing is applied flush with the inside edges of the frame opening. If you prefer to have a reveal edge around the interior edge of the casing, you will need to add a solid hardwood strip to the edge of the frame so the plies of the plywood are not visible.

Tools&Materials pencil ■ tape measure, table saw ■ drill with bits ■ 2-ft level ■ framing square ■ utility knife ■ straightedge ■ finish-grade 3⁄4″ oak plywood ■ spray-foam insulation ■ composite or cedarwood shims ■ 11⁄4,2″ finish nails ■ 15⁄8″ drywall screws ■ carpenter’s glue

How to Trim a Basement Window (standard)

  • Check to make sure the window frame and surrounding area are dry and free of rot, mold or damage. At all four corners of the basement window, measure from the inside edges of the window frame to the wall surface. Add 1″ to the longest of these measurements.
  • Set your table saw to make a rip cut to the width arrived at in step 1. If you don’t have a table saw, set up a circular saw and straightedge cutting guide to cut strips to this length. With a fine-tooth panel-cutting blade, rip enough plywood strips to make the four jamb frame components.

  • Crosscut the plywood strips to correct lengths. In our case, we designed the jamb frame to be the exact same outside dimensions as the window frame, since there was some space between the jamb frame and the rough opening.
  • Cut 3⁄8″-deep × × 3⁄4″-wide rabbets at each end of the head jamb and the sill jamb. A router table is the best tool for this job, but you may use a table saw or hand saws and chisels. Inspect the jambs first and cut the rabbets in whichever face is in better condition. To ensure uniformity, we ganged the two jambs together (they’re the same length). It’s also a good idea to include backer boards to prevent tear-out.

  • Glue and clamp the frame parts together, making sure to clamp near each end from both directions. Set a carpenter’s square inside the frame and check it to make sure it’s square.
  • Before the glue sets, carefully drill three perpendicular pilot holes, countersunk, through the rabbeted workpieces and into the side jambs at each corner. Space the pilot holes evenly, keeping the end ones at least 3⁄4″ in from the end. Drive a 15⁄8″ drywall screw into each pilot hole, taking care, not to overdrive. Double-check each corner for square as you work, adjusting the clamps if needed.

  • Let the glue dry for at least one hour (overnight is better), then remove the clamps and set the frame in the window opening. Adjust the frame so it is centered and level in the opening and the exterior-side edges fit flush against the window frame.
  • Taking care not to disturb the frame’s position (rest a heavy tool on the sill to hold it in place if you wish), press a steel rule against the wall surface and mark trimming points at the point where the rule meets the jambs at each side of all four frame corners, using a sharp pencil.

  • Remove the frame and clamp it on a flat work surface. Use a straightedge to connect the scribe marks at the ends of each jamb frame side. Set the cutting depth of your circular saw to just a small fraction over 3⁄4”.Clamp a straightedge guide to the frame so the saw blade will follow the cutting line and trim each frame side in succession. (The advantage to using a circular saw here is that any tear-out from the blade will be on the nonvisible faces of the frame).

  • Replace the frame in the window opening in the same orientation as when you scribed it and install shims until it is level and centered in the opening. Drive a few finish nails (hand or pneumatic) through the side jambs into the rough frame. Also, drive a few nails through the sill jamb. Most trim carpenters do not drive nails into the head jamb.

  • Insulate between the jamb frame and the rough frame with spray-in polyurethane foam. Look for minimal-expanding foam labeled “window and door” and don’t spray in too much. Let the foam dry for a half hour or so and then trim off the excess with a utility knife. Tip: Protect the wood surfaces near the edges with wide strips of masking tape.
  • Remove the masking tape and clean up the mess from the foam (there is always some). Install case molding. We used picture-frame techniques to install a fairly simple oak casing.


While casing for a window is much the same as for a door, the horizontal elements below the window are different. In most cases, you need to install a stool (often called a sill), jambs, and an apron as well. If the window is set deep in the wall, you will end up with a stool that is also a deep shelf, which may be made of hardwood plywood, solid-surface countertop, or another material.

The sequence here shows a window set about 5 in. back from the drywall. Start with the stool. The board you use should be wide enough to extend in front of the drywall by at least 3⁄4 in., 1 in. or 11⁄2 in. is common.

First, figure the total length of the stool, this does not have to be precise, since it will run past the casing on each side by an inch or so. Position a scrap piece of the casing you will install where it will end up: Take into account the thickness of the jamb as well as the reveals on the window frame and the jamb.


  • Look at the steps ahead to help visualize this. Then make a mark about 11⁄2-in. past the casing. Do the same on the other side, and measure between the outside marks to find the stool’s total length.
  • Next, mark for cutting notches on each side of the stool. Use a square to mark for the width of the notch; allow yourself a gap of 1⁄4 in. or so, where it will be covered by the jamb later.

  • To determine the depth of the notch, use a compass, as shown. If the depth is too deep, measure and mark with a tape measure and square. Find the depth and transfer that measurement to the stool.

  • Do the same on the other side and cut with a miter saw and/or a jigsaw.

  • Place the stool in the opening, shim as needed to keep it level and even with the window frame, and drive finish nails.
  • Cut a length of casing or other trim material for the apron and install it against the wall under the stool, checking the stool for level.
  • Cut side jambs to run from the stool to the reveal mark on the window frame and install with shims to keep them square. Install the head jamb as well.

  • To install mitered casing, mark a reveal line on the jamb. Cut two scraps of the casing at 45° miters and hold them in position against the jamb to test for a tight miter fit.
  • If the joint is wider at one side, slightly adjust your saw and test again until you achieve a great-looking joint. Miter-cut the side casing pieces so the short side of the cut reaches the reveal line, and partially hand-drive a few nails to temporarily hold them in place.
  • Measure across the top and cut the head casing. Position it; you may need to remove the temporary nails in the side casing to adjust for tight miter fits.
  • Finish attaching the casing with 2-in. power-driven nails, or with wire brads driven into the door frame and 6d nails driven into the wall framing.

More Casing Possibilities

Here are some more possibilities for casing windows and doors. All use trim pieces commonly available at lumberyards and home centers, and none call for making miter cuts. And for all, you can choose stained wood or painted trim.

To install this “traditional” style of the casing, attach plain casing (also called sanitary casing) to the sides. Top them with a “fillet” of 11⁄8-in. casing stop or a similar small piece. Then add a head casing of 1x4, and top that with another fillet, this time one that is a bit thicker.

A distinctive “classical” look is achieved with fluted casing attached to the sides. A fillet of lattice is placed on top of that, and then a head casing that is about 5⁄8 in. thick and 31⁄2 in. wide. Place a wider and thicker fillet on top of the head casing, then attach bed molding below the top fillet.

This one is simplicity itself and can look either rustic or modern, depending on the materials you use. On the sides, install plain (“sanitary”) casing, then install a head casing of 1x4 (which is 3⁄4 in. thick). Install the head casing so it overhangs the side pieces by 3⁄4 in. on each side.


Brick molding, as shown here, is the most popular choice for outside window and door trim. Here, I use PVC vinyl brick molding, which will never need painting, lasts forever, and is easy to work with.

  • Measure the opening. If there are any masonry or old caulk protrusions, chip them away or plan for a trim size that takes them into account. (You can always install a thick bead of caulk around the molding, so there’s no need to try for a tight fit.) Measure the diagonals.
  • If they are equal, the window is square; if not, remove the fasteners and use shims to bring the window square. You can draw a reveal line, or just plan on making the inside of the trim 1⁄2 in. wider and taller than the inside of the window frame, for a 1⁄4-in. reveal all around. Also, a measure for the width of the molding all around. In this case, the bottom trim will need to be narrowed with a rip cut.
  • Miter-cut trims pieces, with the short side of the miters running from revealing to reveal. You can’t hook your tape measure to a miter-cut end, so “burn an inch”: Hold the tape at the 1-in. mark and make the cut mark at a point that shows 1 in. longer than the desired length.

  • The bottom piece rests on a sill that is sloped down away from the house. So the piece will follow that line, rip-cut with a table saw or a circular saw set to a slight angle.
  • Working on a flat surface, assemble all four pieces of trim with four finish nails driven into each corner.
  • Where the bottom piece was rip-cut, you will need to cut off a little nub.
  • Set the trim assembly in place and nail or screw in place, taking care not to drive fasteners where they will interfere with the operation of the window.
  • Paint the trim. Finish with a bead of high-quality caulk. If a gap is wider than 1⁄4 in., first push in some foam backer rod.