How to Install Door Jump Extension

Door Jamb Extension Installation Guide

Sometimes framing studs don’t match the walls of doors, if it happens then installing a jamb extension in the door will be a reasonably perfect operation for your home renovation. Whenever anyone adds new siding in his older home or changes the walls in some other way by adding panelling to an inner wall to create an additional wall, can both cause this.

The space between the walls where the posts are placed alters as a result. In order to fix this, the jambs must be replaced. For doing this, you can either buy a door with wider jambs or you can make and install jamb extensions. When the wall has non-standard dimensions, the extension jamb installation is the perfect option for you.

  • What is a Jamb extension?

The word “jamb extensions” is used to describe the wood or other material that widens the jamb so that the window occupies the entire depth of the position from the outside to the inside. This interior material is frequently plywood or panelling.

What is a Jamb extension


  • Process of Installing a door jamb extension

With the help of jamb extenders and an inside window feature, your frame may accommodate windows with different depths. Your window can lay flush with your interior wall by extending door jambs to the perfect length needed.


  1.  Set the Jamb into the inside part of the frame

For an exterior door or the wall surface on the outside of a room, first, remove the door and then insert the new jamb into the door frame with its outside edge flush with the wall. Measure the distance with tape and measure between the wall and the stud’s edge. To accurately measure the distance to the ruler, lay a straight edge across the wall and past the doorway.

set the jamb properly into the door

      2. Take the proper measurement

According to Innovative Building Materials, as walls’ thickness might vary slightly, measure the difference several times, including at the top, on each side post, and make sure the post is firmly fixed to ensure accurate measurements. Get the right amount of wood pieces by measuring the post boards’ width, which is typically 3/4 inch; either buy new material at the hardware shop or determine whether the old posts can be reused.

      3. Set the table saw perfectly

Use the broad dimension which will fit your space and set the table saw to the width required for the extension. Rip three boards, one for the top and two long enough for the sides, to this width. Cut three pieces—one for the top and two for the sides—after measuring the post to establish the required length.

      4. Join all the pieces together

Test the extensions on a level surface before using wood glue to attach them to the interior surface of this frame. Using fine nails and adjustable clamps, fasten the parts together, according to hanging doors, roughly a foot apart. Use a set of nails to drive the nail heads beneath the surface of the board, and then use wood putty to fill the holes.

      5. Now set the jamb properly into the door

To check that it fits, take the clips off and lean the extended jamb up against the door frame. In any areas where the extension is a little too wide, clip it off with a brush. A wood spatula or filler should be used to join the two parts. finely and smoothly sanding with a hand sander. It was installed like a standard jamb and seamlessly stretched the jamb.

  • Kits you will need for installation 

  1. Jamb extender for header
  2. Lockside jamb with hinge extender
  3. One piece of sill extender
  • Other equipment
  1. Hammer, pillars, and caulking gun
  2. Galvanized thread screws (2 -1/2”)
  3. Proper galvanized finish nails ( 2-1/2”)
  4. One dimension Hacksaw
  • Step-by-step installation process

Remove any brick moulds from the door if there are any. When removing the brick moulds, be careful because they can end up being utilized again. Brick moulds should be free of all nails.

  1. The sill extension should be correctly snapped or placed onto the sill.
  2. Apply a continuous bead of caulk to the jambs’ three front sides.
  3. To use the galvanized end nails, attach the jamb extenders at a distance of about 1″ from the ends and with a spacing of 8–10″. Make sure the rounded jamb portion is inside and the extension aspect with grooved lines is at the front. The sill extender should mate with the dadoed side of the aspect jambs.
  4. The posts should be tapped to fit the sill extension screw boss after pre-drilling holes in the hinge’s underside. Using fine thread screws, fasten the upright extensions to the rocker extension.
  5. Use galvanized nails to repair the brick facings to the jamb if necessary; place them close to the original nail holes. To find and align brick trim to this line, use the slot lines marked 1/2 inch from the inside edge of the jamb.
  6. The jamb’s position Insert the clip such that the tab meets the accessory slot in the frame and the straight wall extends past the window frame. Tap the clip gently with a mallet until it is completely seated in the attachment slot.
  • Benefits of door jamb extension

  1. Aesthetic looks of your house

The primary consideration when selecting a jamb extension is aesthetic value. Jamb trims make it simple to improve the appearance of your door frames, which will increase the aesthetic of your entire home.

Benefits of door jamb extension

     2. A door opens and closes smoothly

Everyone wants their home’s windows and doors to operate without issue. Your windows and doors can operate without issue if you use a jamb extension. The paneling also makes it easier for the doors to open and close without making any noise.


Jamb extensions help homeowners save a lot of money by protecting and removing the need for upkeep or painting. reduces a variety of costs necessary for efficient door jamb maintenance. You may benefit from a protective jamb cover for your door and window jambs by learning what jamb covers are and how they work.

Now YellowCarpets brings some different kinds of home-related articles for you. In this article, we discovered some innovative problems which you face in your daily home maintenance. We also upload some best DIY life hacks on our Youtube channel which can also help in your home renovation.

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