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We purchased a house in 2011. When we moved in, the front door wouldn't open all the way; it drug the floor at about 70 degrees from full open. Enough to squeeze by it, and you could force it all the way open, but it was rubbing the floor pretty good. I figured this was an easy fix and didn't pay too much attention to it. A few weeks after living there, I realized that the reason the door was dragging was because the door was not plumb. The top of the jamb was leaning into the house, so as you opened the door, the knob side of the door swung downward as well. I devoted some time to remedy that situation and quickly realized my next hurdle.

Now that the door was plumb and would swing all the way open, I also realized that the bottom seal/weatherstripping was missing from the door. The "new" hardwood floors (installed prior to purchase) were great, but the person that installed them failed to realize that the thickness of the flooring would impede the ability of the entry door to seal properly. Low and behold, the reason is because the threshold is lower than the floor height. So for two very cold winters we have had a large gap under our front door. We plug it with draft stoppers, towels, etc., but it still lets in a ton of cold air. I decided that this winter would be different so I started researching my options.

In most cases, it's easier to raise the header and keep a standard door size, but the soffits on the front of my house are directly above the door frame, so I have ZERO room to go upward. I need a door that is approx. 1 1/2" shorter than the standard height and I can build up my rough opening from the bottom. I priced doors from everywhere in town, and they are all special order ranging from $450-$700 for a basic, 6 panel, steel clad door. Keep in mind that a basic, 6 panel, steel clad door can be purchased at any home improvement store for just over $100. So, we're looking at $300+ to cut 1 1/2" inches off??? No thanks. After researching off and on for a while, I decided to tackle the project. Follow along if you're still interested.

Step 1: Gather Tools and Supplies

You'll need a variety of tools to complete this task exactly as I did it. Some tools may be substituted for others, this is just what I used. Note: you will NOT need a torch to complete this task. :)

Tools:

  • normal hand tools - screwdrivers, pliers, hammer, etc
  • drill
  • router with straight bit
  • circular saw
  • reciprocating saw
  • utility knife
  • air compressor
  • air stapler
  • straightedge (at least as long as the door is wide)
  • square
  • pencil
  • caulk gun
  • sawhorses
  • clamps

Supplies:

  • replacement steel entry door
  • Liquid nails
  • 1 1/2"-2" staples
  • scrap wood

After some research, I purchased my door from Menards for two reasons. The first is because they regularly go on sale for $119. Second because I think it is a better built door. The doors are made by Midwest Manufacturing, who has a door comparison here. I assume competitor H and competitor L refer to Home Depot and Lowes, but that's only an assumption. I do have experience with the Reliabilt brand door from Lowes, and my opinion is that this Menards/Midwest MFG door feels like a better built, heavier duty door.

Step 2: Prep the Door

This process will be done in two parts - cutting the door and then cutting the frame to match the cut door. Before you begin, remove any fasteners that hold the door into the frame during shipping. This door was held in by two small nails through the lock side frame into the side of the door. Remove the hinge pins and remove the door from the frame.

Lay the door on the saw horses. You may want to use towels or pipe insulation or carpet scraps, etc over the sawhorses to prevent scratches. This door came primed, but need to be painted anyway, so I just used some cardboard over the sawhorses. If your door is pre-finished take extra care to prevent scratches.

Next, determine exactly how much you need to remove from the door. I measured down from the top of my existing door and determined that the bottom of the door needed to be 1-3/8" shorter to allow room for the door to swing open and clear a doormat on the floor.

Back to the new door, remove the bottom weatherstrip. It's just press-fit into the bottom of the door. It should pull right out, but if it's really tight, gently pry it off with a screwdriver or narrow putty knife. With the bottom seal removed, you can see how this door is constructed. The sides of the door are wood, while the top and bottom rails are composite (i.e. plastic). The steel "skin" of the door is folded/crimped under the door and around the side rails. This is what is referred to as a "thermal break". The steel skin exposed to the outside temps would transmit some of that cold/hot temp to the inside if the inside steel skin was touching/connected to the outside skin. To prevent this, the manufacturers separate ("break") this thermal conductivity by means of dissimilar materials (i.e. wood/plastic/foam). Not all doors are manufactured this way, so it's something to keep in mind when purchasing a door (see comparison chart link in step 1).

Now to mark where to cut. You'll make two marks on each side. Measuring from the top, mark how long you want the final length to be. Mined needed to be 77-5/8" so I marked this as my "FOLD" line. I then measured another 1/4"- 3/8" past the fold line for my "CUT" line to leave some material that can be folded under later on. This extra length may vary from one door brand to the next.

Flip the door over and mark the other side using the same method and measurements.

Step 3: Cutting, Gutting, and Plugging...

These doors cut very easily. While you may think that you need special equipment to cut steel, you don't...at least in this case. The steel skin on these doors is fairly thin. This door uses 0.022" steel, which is less than half the thickness of a U.S. dime.

I used a battery powered 5-1/2" circular saw (trim saw) with a standard blade. I set the blade depth just below the thickness of the steel. I was unsure how tall the bottom rail was and didn't want to risk cutting through it too. If you're cutting off more than 1-1/2", you could set your blade depth deeper than I did.

To gave my saw a guide to run against and keep the cut perfectly straight, I measured from the edge of the blade to the edge of my saw's base and clamped a straightedge to the door (see pic 1). Cut through the first side of the door, then flip and repeat.

NOTE: this method produces small steel shavings which fly everywhere. Use proper safety equipment - goggles, gloves, etc. I actually wrapped a bandanna around my face too.

Something to consider, especially if your door is prefinished, is a way to protect the door from scratches when pushing the saw across the door. Use masking tape or have a helper vacuum the shavings as you cut to prevent shavings from getting trapped between the saw base and the door. I ended up with a pretty long scratch on both sides of the door, but this door needs to be painted anyway.

With both sides of the door cut, you need to clean up the bottom rail to reuse. I found that a 1" chisel fit perfectly to scrape out the foam from the bottom rail. This door is injected with a polyurethane foam after assembly via a hole in the bottom rail. There is is thin plastic strip that acts as a one-way valve to keep the foam from coming back out.

Next is to remove some of the foam to make room for the bottom rail. You only want to remove foam to the proper depth so the bottom rail will be at the fold line. The easiest way to accomplish this is with a handheld router so you can set the depth and it be the same all the way across. I chose to use a straight router bit in a drill and do it by hand, constantly checking the depth of my cut (pic 6). If I do another door in the future, I'll use a router.

Test fit your bottom rail (pic 8) and mark where the wood side rails need to be cut down (pic 9). You'll also need to cut a little tab of steel off of each corner so the steel can be folded under the bottom rail. I used a recip saw to make these cuts (pic 10 & 11).

To trim the wooden side rails, I used a router, but because the surface that would support the router at this point is just two edges of steel, I needed to give a better support surface. I clamped some scrap wood to each side of the door to give the router a larger surface to ride on (pic 12). I set the depth of the router to cut so the wooden side rails would be flush with the bottom edge of the bottom rail once installed. In my case this was 3/8". Cut the wood rails and seal them off with some paint (pic 14 & 15).

To re-install the bottom rail, you need to use a solvent free adhesive to prevent it from eating away the foam inside the door. Just look at the label and see if it's safe for foam. Apply the adhesive liberally on all four sides of the door cavity (pic 17). Insert the bottom rail until it's fully seated against the foam. Use a rubber mallet (or hammer wrapped in a rag) to slowly bend the steel under the door (pic 18). Once the steel is bent under the bottom rail, flip the door over and repeat.

Finally, reinstall the bottom weatherstrip seal. You should have a near factory finish.

Step 4: Modify the Frame

Now it's time to modify the frame to match the new door. It is better to do this AFTER the door has been cut down, because you can adjust your cuts in case the door turned out a bit larger or smaller than you originally planned. Take the total amount you removed from the door and measure that distance up from the bottom of the frame. Remove any corner seals that may be along this cut line.

You'll need to remove the bottom threshold by gently prying and pulling the staples that hold the threshold to the frame. Mine used 2" long staples (pic 3). You can see the adjustable sill in this threshold. Not all doors have this, so keep this in mind when purchasing a door to cut down. An adjustable sill gives you a little error room if you don't get things cut perfectly.

Pull back the weatherstripping (pic 6). It's just a friction fit into a kerf (saw cut) in the frame. Use a square to mark the cut line on both sides of the board. Cut the bottom of the frame (pic 7). I used a recip saw, but any saw could be used. Be sure to save the scraps that you cut off. You'll need them.

Now that the bottoms have been cut, you'll notice that the door stop goes the entire length of the frame (pic 8). The stop needs to be cut away to allow the threshold to fit back in place. The easiest way to transfer the cut marks is to use the piece you just cut off as a template. They say a picture is worth a thousand words so see the animation (pic 9) for this process. With the angles marked, use a circular saw with the blade depth set to the thickness of the door stop, make a single cut through your marks (pic 10). Once the mark has been cut, make successive cuts BELOW the first cut. You can then break off the tabs with a gentle tap with a hammer (pic 11). Clean up the surface with a sharp chisel (pic 12). Put the weatherstrip back into place and trim to length (pic 13). Repeat on the other side of the frame.

The rest of the process is pretty straight forward, but unfortunately I didn't get any pictures. The threshold should now fit nicely under the trimmed door stop and the bottom of the threshold should be flush with the bottom of the frame. Before attaching the threshold, use some 100% silicone caulk on the edges of the threshold where it meets the frame and the door stop. **Be sure that you don't get caulk in the channel for the adjustable sill as this could cause the sill to become permanently fixed.

To attach the threshold back to the frame, it is recommended that long staples be used. Fortunately, I have a friend in the construction business who let me borrow his air stapler. If you don't have access to a stapler, I would recommend using a decking screw (something weather resistant) at least 2" long. You also want to pre-drill your screw holes to keep the bottom of the frame from splitting.

Once the frame is finished, reinstall the door into the frame, refit the hinge pins, and refit the shipping fasteners to keep the door from moving.

Step 5: Final Thoughts

The thought of cutting a brand new door was daunting at first. This process took me a couple evenings to complete. Each step took me a while as I contemplated the exact process that I wanted to do to avoid mistakes. Now that I've done one door, I'm confident I could do another within a few hours.

It's recommended to wait until after the door is completely installed before applying any finish to prevent marring, scratching or chipping the finish during installation. Since I'll need to modify my rough opening where this door is going, I haven't installed it yet. We've had 90+ degree days lately, so I'll wait until closer to fall for milder temps.

Thanks for reading. If I left anything out or if you have any questions, feel free to ask.

<p>Wow, your guide was incredibly useful and closed the deal on even attempting this task. I had the help of my cabinet-maker son-in-law, which helped a great deal. We finished this in a little over two hours following your instructions. I'm convinced we would have taken an additional 4 hours, minimum, without your instructions. We also, more than likely, would have butchered a perfectly good door. ;) The only significant deviation we made was that we cut the bottom off of the frame and then removed the staples holding the wood from the threshold. Great job, thanks!</p>
Great. I was in the same boat as you and did a bunch of research before deciding to tackle the project and finally decided to bite the bullet. There's not much information about out there about this task that I could find. I'm glad that I was able to help.
<p>Great guide!</p><p>Did you think about building up the bottom jamb instead of removing the whole frame and cutting it then? What made you remove it instead?</p>
<p>Thanks for the excellent guide.</p><p>I saw one other questions similar to mine but I want to make sure before doing more than is needed. I need to remove 1/8&quot; or possibly 1/4&quot; off the bottom as we installed hardwood and the bottom weatherstrip is rubbing on the wood - where the carpet it would just glide over.</p><p>I'm not sure how to go about removing just 1/8 or 3/16&quot;. Could I just unfold the bottom metal that is crimped over, remove some internal foam, remove just a tiny bit of the wood on each side and then fold that same metal back underneath? <br></p>
<p>I'm assuming the threshold is still above the new wood floor? If so, then you can get by just cutting the door to be shorter, either from the top or the bottom. I'd pull the hinge pins and lay the door on some saw horses and pull the weatherstrip off the bottom and assess if it would be easier to modify the top or bottom of the door. Modifying the top will require relocating the hinges as mentioned earlier, but you could likely just router the desired length from the wood/plastic piece on the top and not have to worry about removing any foam. I'm not sure if any of this was helpful, but good luck with whatever you decide. </p>
<p>For that small amount, I'd be tempted to cut 1/8&quot;-1/4&quot; off the top of the door and cut new hinge mortises in the door frame to move the door and hinges up that amount. You'd have to patch in a little where your hinges used to sit, which would be easy to hide if the door frame is painted. A stained door frame would be hard to match colors. </p><p>The top of the door is assembled basically the same as the bottom, except that there isn't a weatherstrip to cover the folds. </p>
<p>I noticed you cut back quite a bit off your door, revealing that bottom insert piece. If I only want to take off let's say 1/4&quot;-1/2&quot; will I be able to just pry/pull out that piece if I bend back the metal lip? How would you suggest I go about it?</p>
Well, the bottom seal fits into the grooves in the bottom piece, so if you cut those off, there will be nothing to hold the bottom seal. You'd need to move the bottom piece inward by 1/4-1/2&quot;, which would require all the same steps that I did, just different lengths removed.
I'm wondering if I can cut down a swinging glass door that was installed at my house at the bathroom entrance but it ended up being a few millimeters too wide at the top. Any ideas on how I could possibly shave it down to fit through the marble frame? Perhaps a carborundum stone, or will I need professional help? Who could I go to for help?
<p>thanks man. you're steps were very helpful and gave me the confidence. it was a hot and dirty all day project, but it was worth it. absolutely had to have the respirator and goggles. my body was totally covered in metal, foam, and wood shavings. i ended up having to reroute because i didn't go deep enough the first time. crouching to route with precision wasn't easy. no dust collection of course. great pics, comments, and the gif was great. I can see how someone would want to charge $200 for this service, which is probably worth the cost.</p>
<p>Thanks for this! I have to cut 3&quot; off a garage entry door.. these instructions will hopefully save me a few hundred bucks. </p>
It's not too bad of a process if you don't rush through it. Let me know if you have any questions. I'll try to answer them quickly. Good luck.
<p>How come you didn't trim the top of the door?</p>
<p>The top could be cut using the same method, but there were two reasons why I didn't. The top of the door frame is rabbeted (image from google) and is harder to duplicate than the straight cut needed for the bottom. It's also closer to eye level, so if you don't have a tight joint it will be more noticeable. When it comes to the door itself, the weather seal on the bottom covers any potential uneven cuts to the steel skin. A bad cut to the top of the door, while above most people's eye level would be in plain sight.</p>
<p>Has anyone tried cutting a strip off the side of a steel door to make it narrower? Would this be possible? Thanks</p>
I would think it would be possible, but it would be a bit more difficult, and the process may vary depending on how the door is constructed. If you look at the photos in step 2, you can see the profile of the side frame of the door I used. The steel skin is just folded over and into the wood. The wood acts as a thermal break (to keep cold and hot from transferring from the outside skin to the inside skin of the door. The only unknown is whether there is internal bracing near the knob or hinges. I'd probably try to find an old steel door from a resell or surplus shop and practice on it first.
<p>I just used this process yesterday to make a 32x80 door into a 32x78 entry door. I used a Makita 18V circular saw with the factory blade to do the main cutting. Then I had a Dremel with a cutoff wheel to do the fine tuning and edge trimming where the metal doesn't get bent over again. Just make sure to measure all of the overhangs and setbacks on the frame so your threshold goes back in the same way after. The picture with the tape measure are before the door was cut, but after the factory door sweep was removed to get accurate measurements.</p><p>Once the door was cut and the factory sweep was reinstalled, I put the threshold back on to double check all my measurements before cutting the frame.</p>
<p>Also, this method saved over $200 as compared to ordering a 78&quot; tall door.</p>
<p>thank you that what I'm have to do with my door Do you think if i use grinder to cut metal door would it works what kind of saw you use for cutting </p>
<p>I want to put a new door on my basement door - which opens into a stairwell/breezeway, as my daughter is now living in the basement, I'd like a better, stronger, more solid, less noisy (lol) door so these instructions are so clear and helpful, I'm feeling confident we'll be able to figure something better out. Thank you! </p>
<p>Very good pictures and a great explanation, you gave plenty of details in your writing and the GIF was a great way to demonstrate how to mirror the approx. 6 degree sill angle requirement. This is a job rarely done by a homeowner but you have shown that the difference between me (contractor) and a homeowner is that I do it often, so I get to learn all along the way. </p><p>Suggestions: </p><p>Use a panel blade installed backwards in your circular saw for a cleaner cut with smaller metal shavings. Also use a hand held router and straight bit to mill out the foam and wood before reinstalling the bottom rail. The bottom rail should be set in a non solvent-based adhesive to set the bottom rail (solvents will melt the foam insulation). And an angle grinder works great to trim the small pieces (on the side edges) of metal back to allow the fold to take place.</p><p>A professional would make the door cut approximately 1/4&quot; longer than needed and then fold that 1/4&quot; tab under the bottom rail after reinstallation. You can do that fold with a hammer, just keep tapping along the metal (it's thinner than a dime). This prevents rust and holds the bottom rail securely while providing a thermal break.</p>
<p>JohnS45, thanks for reading through my instructable. It's nice getting feedback from a professional, but other than using a backwards panel blade in my circular saw and using an angle grinder to trim the side tabs, I had already covered the rest of the suggestions in the instructable. If read through step 3, you'll see that I used a router bit to mill the foam, a router to mill the wood side rails, a foam safe adhesive to reinstall the bottom rail, and folded the remaining tab under the bottom rail. I even mentioned that the steel skin of the door is thinner than a dime. :) Again, thanks for taking the time to read through it. If I DID forget something, let me know I'd be happy to make an edit to correct things. </p>
<p>Change your main image to show the prep or the process, please. Otherwise, this is a wonderful project with excellent writing and photos. Thanks for lighting the path forward for the brave and intrepid and curious who happen to also have overlarge steel doors. </p>
<p>Thank you. I couldn't find a &quot;catch all&quot; photo, but I changed the main image. </p>
<p>Well done! Your careful forethought and observation of the door's construction (and excellent documentation) have likely saved many future mistakes for those of us who might think about cutting down a door. Thanks for this very useful Instructable! </p>
<p>Thank you. I hope it is useful for others.</p>

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Bio: I'm a husband and father that loves working in the garage. From sewing to welding to wrenching on engines and everything in between.
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