Install Pre-hung Interior Door, Start to Finish

Installing a pre-hung interior door on a frame is something that scares a lot of people, but it doesn't need to. I'm going to show you how to do it and how to finish it as well. It's actually easier than you think and doesn't require special tools, you obviously still need some tools, but they are basic tools. Let's do it!

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• Pre-hung door
• Shims
• 4' level
• Brad nailer
• 2" and 1" brad nails
• Drill and/or impact (optional)
• Countersink drill bit (optional)
• 2.5" deck screws (optional)
• Drywall spackle
• Sanding sponge
• Trim caulk
• Trim paint
• Utility knife
• Paint brush (small)
• Paint roller (small)
• Square
• Circular saw (optional)
• Pencil

First things first, double check your flooring to make sure it's level, or at least pretty dang close. If your floor is way out of whack, you'll need to repair that first. If it is super close, but not quite perfect, maybe 1/8" out, take the side that is high and on the door frame side that will sit there, you can take a circular saw and cut that off the bottom of the door frame by standing it on it's side and use a square to make a straight cut (I have another video about how to make a straight cut on my YouTube). This will lower the high side of the door frame down to match the other side. If it is out less than that, we will just shim it ever so slightly because less than 1/8" will not be noticeable. I also like to check the sides of the rough opening the door will be going into, just so I know how far it's out, this just gives me a quick heads up for later so I know where the biggest gaps will be for shims.

Now we can pick up the whole assembly and slide it in the opening. If it is a hollow core door it should be fairly easy to pick up, just awkward (hollow doors are most common). Solid core doors as very heavy and will need a couple people (Solid doors are fire and sound rated). Make sure it is sitting pretty flush and close in the hole and then open the door 90 degrees from the frame and shim under it so that it doesn't fall. You want enough shims under it so that the top of the frame is sitting flush with the drywall.

I'm sure most people have seen shims, but for those that haven't they are tapered. We want to install the shims so that they are opposite of each other so it creates a even thickness. If you install them so the big ends are on the same sides they will twist the door frame in the hole and that is bad. Now with 2 shims held correctly, install them above the top hinge between the frame and stud. Now, don't apply pressure to the frame, just take up any slack thats there and they hold themselves in place. Also, adjust them to each other and the frame by sliding one or the other in or out to take any gap up. You don't want one side of the shims to be tight, but the other side has a bunch of back and forth play. If that happens slide that big side in further to remove the gap, and the other out enough so that it is perfect on the from and backside. If the door frame is moving a little bit on the other side you can shim it into place quickly for now just to hold it.

Once that is done we can fix it to the stud. Using a small straight edge (I used a shim) to make sure the frame is flush with the drywall, I used a 18 gauge brad nailer with 2" nails, and fire 2-3 nails on each side of the door stop, going through the shims as that will keep them in place and stop the frame from bowing. If you do not have a brad nailer (or you are installing a heavy door) you can use a drill, countersink bit and screws. Again, make sure it is flush with a straight edge and go through the door stop (the part that the door closes against) with your countersink drill bit just deep enough to sink the head of the screw. Again, go through the shims with this, you may want to hold them in place so they don't spin in place from the drill. Then add your deck screw. Take care to only tighten this just enough so that it's held in place and snug, we don't want to over tighten it and contort the frame.

From there go down the door and install the center and bottom shims the same way. Just above the hinges and just snug without pressure, and no slop if you shake the hinges side to side (make sure the depth is correct from and back). From there grab your level and check the door frame and make and adjustments in or out as necessary. Then also check it the other way to make sure it is plumb, and kick the bottom in or out as needed but it shouldn't take much. Once everything looks golden, attach it to the stud behind it the same way as the top. Nail or screw through the shims working from the middle to the bottom.

Now that the hinge side is installed, go ahead and remove the shims from below the door and close it slowly. Keep and eye on your gaps and listen to it. Make sure it doesn't bind or anything, but if done correctly it should close nicely. Then if you look at the top and striker side it should have a nice even reveal gap. The lower parts may still rub on each other as the frame may be twisted yet, that ok we will fix that next.

Now about the same height as the other side, slide some shims into place on the top striker side. Now instead of using the level to check the frame, we will be setting everything referencing the door itself. Close the door and check your reveal (the gap between the frame and door) and make sure it's even, if it isn't just slide the shims in or out as needed till it's good. Keep referencing the door. Also if you need to lift it up just barely, barely, do that too. You won't see a 1/16" gap at the bottom, but a calibrated eyeball may see it on the top reveal if staring right at it. Once it looks good attach it to the stud.

Now we will move to the bottom. Because my frame is real wood and not MDF, it had a slight twist you can see. I had a huge gap where the shims needed to go so I had to put pressure on the frame there to close the gap. When I did that, the twist in at the bottom was touching and neede to be pulled back. With the main shims in place and my gap closed, I nailed the frame to the stud. Then to correct the bottom corner I did the same thing as the middle of the frame by the striker. I had the same problem here, the door and frame were touching. I held some shims in place and left some play, closed the door and pulled the frame back so it was touching the shims till the gap looked perfect. Open the door and fire a nail through the frame and shims, close the door and check the reveal. If it looks good, finish attaching it.

Now it is mounted and standing in place. You can open and close it and it should work like a door now. Just a few more things to do. Take a sharp utility knife and make a deep score along the shims on the left and right side flush with the drywall, you may want to make a couple passes, and then snap them off with your hand. You can use a hammer to snap them off if you want, and if you have a oscillating saw you can use that to cut the shims as well. Then take some drywall spackle and fill in the nail or screw holes, I use my finger but you can use a putty knife if you want. Press it in deep to fill the hole, then add a little more on top so the hole is overfilled and let it dry.

Add your pre-painted trim to the door as you see fit. I am using flat stock trim you can buy in bundles from most big box stores. I am leaving a 1/4" reveal from the door frame to the trim, I marked it out with a adjustable slide square set to that and marked my corners, then the bottoms and middles. Line your trim up with those marks and get your measurement for length. You can picture frame the corners if you want, but with this flat stock trim you can also flat mount them on top of each other. To nail the trim to the frame I used 1" nails, then in the center of the trim I nailed it to the stud using 2" nails. Fill the nail holes in the trim the same way we did on the frame.

Now to make it look pretty, we need to cover some sins. There is an old saying, do your best and caulk the rest. Well, there are always seams between frame and trim that need to be caulked, but if you have gaps anywhere, this is where you hide them.

Remove the door and set it aside to be painted with whatever trim paint you are using. Remove the hinges from the frame and set aside with the screws. Do not leave these in place people, it takes 30 seconds to remove them and will not look like a hack job with paint on them this way. Not much looks worse or dates something than hinges and hardware with paint on them.

Now to start caulking, you want to use a trim specific caulk because they have more stretch and resist cracking. As you can see I have a gap in the top corners of the door frame, this is typical (though not usually this large) and need to be filled with caulk. Then apply a thin bead to the whole door where the trim meets it, top to bottom, left and right, and don't forget the inside of the closet in my case, that trim too. Then wipe it off with your index finger, dry or wet doesn't matter, I prefer dry in the name of speed and that's the way I was taught. Wiping excess caulk off on a shop rag as needed. Then as a final pass I like to go back with my pinky finger, giving it a good press in to the corner to give myself that nice crisp edge back and not a rounded corner.

With the caulking done and drying, we can sand the nail heads flat. Take a sanding sponge and sand down all the spackle on the nails till it is flush with the frame and trim. Sand till it is flat, should take much, we don't want to sand through paint and primer.

With the caulking dry, nail heads sanded flush and everything looking to your satisfaction we can paint. If you need to make any final touches do it now. Take your same trim paint and a small brush and paint all the caulking seams between the frame and trim with 1 medium coat of paint. Not heavy enough to run, but not so thin it doesn't cover, doing this method you only need to add 1 coat. Using the same small brush paint the top corners back into the frame on the top and sides about 2", then using a small 2" or 3" roller apply a thinner coat than before, but thick enough for full coverage, go up and down on each side of the door stop on the frame, then do the door stop as well. if you have a run anywhere just touch it with the roller and keep smoothing it out till it looks good. We don't want any brush strokes so we roll the frame, but we also don't want it globby and running either, just touch it lightly with the roller so it is smooth with light texture. When you get to the bottom slide a piece of paper underneath so you can paint right to the floor.

Once it is all dry and cured for a day or so, add the door back on. I prefer to install the hinges to the frame first. If you are using a drill, take care to not overtighten any of the screws in the door or frame as they are small and it is soft wood, they strip easy. Basically just tighten till they bottom out and stop, you may want to check it with a screwdriver by hand if you are uncertain. Then with somebody helping hold the door, guide it into place and attach the door to the hinges. If a hinge doesn't line up perfectly, loosen the frame side screws a little, screw it to the door, then tighten the frame side again. Attach your preferred door handle and striker. Close the door and see what you did.

I hope your project turned out awesome!

Let me know what you think, or if you have any questions and I'll get back to ya! You can tag me or email me directly!

Thanks for stopping by and have fun!

CanaDIYan

canadiyanjesse@gmail.com