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Installing a Pre-Hung Door

Tools that you’ll need

o 6 Ft Level, or 4 Ft one will work

o Framing Square

o Wood Shims

o Caulk (Latex works the best)

o Drill with Phillips bit

o Hammer

o 2.5 inch finish nails, or pneumatic finish nailer

o Tape Measure

o 3 inch screws x3

o Nail set

o Utility Knife

Preparing the Rough Opening

Measure the width and height of the door opening. Be sure to check that the rough opening is the correct size for the door. The rough opening should be slightly larger than the door by ½ to 1 inch both in the width and height.

With your level check that the rough opening is plumb, that walls are in plane with each other. If you notice any irregularities fix them now. Check the door frame for square by pulling a tape diagonally from upper left to lower right, both measurements should be the same. Use a framing square on the inside corners both top and bottom are at 90 degree angles. Fix any concerns now.

Preparing the Sub-Floor

The subfloor is the foundation of a door and where the threshold sits should be solid and level. If floor is not level side to side you can add shims and glue down or use a concrete leveler. If door height is a concern shims can be used or even a wood sheeting. Using the proper products is critical, especially if water is a concern. Such as ice/water membranes or metal flashing. Start with a level sill.

Caulk the Subfloor & Underneath of Threshold

Place the door on sawhorses or on its side remove the section of wood from bottom of threshold (this is only for shipping purposes). Apply a large bead of caulk across the width of the threshold and along the front edge. Apply a few large beads of caulk parallel along the bottom of threshold, which will rest on the sub-floor.

Apply large beads of caulk just as above this time on the subfloor use a generous amount of caulk to ensure wind and water do not become present. Always install doors before the adhesive sets. If installing a patio slider or French doors apply construction adhesive under the mullion where the door meets the center.

Placing the Door

Tilt door back towards you so front edge of threshold is resting on the surface and caulking is partially on the sub-floor area making sure that when in the upright position both caulked surfaces will meet. If installing an exterior door, some doors will already have trim installed on jamb this will help to set the door. Doors typically come with a plastic threaded screw and nut to keep door and jamb together remove only the nut and slide screw in just enough to install door this helps keep door and jamb together but not tight. It’s a good idea to use some scrap material such as 2×4 a few inches long or some shims to put under the door at the furthest point when you open it, as the jamb is not affixed to framing the door will just tip to where all the weight is making it difficult to plumb and level the jamb.

Secure Hinge side of Jamb

If the door is standing on its own remove one screw from the top hinge if the rough opening is plumb and nice the push the hinge side so it hits the 2×4 then using a 3 inch screw start screw making sure you like where the door planes nice with sheetrock drive 3 inch screw all the way in this should suck the door up tight then check for plumb. A tip is to pull the weather stripping out of its track on sides and top this is where you will secure the jamb to 2×4 with 2.5 inch finish nails so you don’t see them when the weather stripping is re-installed after securing with finish nails then you can take one more short screw from each hinge and replace with a 3 inch screw. Remember to only secure if plumb and jamb planes nice with the sheetrock. On the side bored for a lockset and or deadbolt use four sets of shims some at top, some in middle at each lock strike and a set at the bottom. Set the reveal from the jamb to the door this should match from top to bottom and be even, it should be 1/8 inch gap. You will have to close and open door a few times to get it perfect check for plumb and make adjustments try to keep the reveal the same all the way down, the top should be close or the same as the lockset side. If you like the results the hammer in 2.5 inch finish nails to secure jamb just like the hinge side you will need to hammer in some 2.5 inch finish nails in the field of the jamb where shims are just one or two nails in weather stripping area will not hold the shims when cutting with a utility knife, use a nail set to countersink. Same goes for the top shim, hammer 2.5 inch finish nails be sure to check for proper reveal. Re-install weather stripping and check for proper closing door should be flush and plane nicely with jamb face. Score shims with utility knife and break off some shims will need to be scored a few times as they are thicker, break in the opposite direction of the score.

Installing the Hardware

With the door open place strike plate on jamb side mark and pre-drill with 1/8 inch to ensure that the screws are centered correctly, do the same on deadbolt strike plate. You can use the 2 inch screws that come with the lockset you can also use 3 inch screws on both strike plates this way is more secure over tighten screws it could split jamb. If your door did not come bored on the door side to accept the tang and plate you will need to cut this area out using a ¾ inch or ½ inch chisel. First place tang assembly in the hole and mark the outline using a pencil, place chisel with the bevel part facing inward tap all the way around marked section going 1/8 inch deep from here use chisel bevel side down and go slow and smooth careful not to remove any part except for the marked area. Be careful on the sides as they will become thin and easy to knock out. Assemble all parts and check for proper alignment. Fill nail holes and paint.

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