Door Repairs: Why You Need to PLUMB a Door

Do you have a hard time locking your front door? Or find yourself placing a door draft stopper under your door when it gets cold? Most of these problems are due to a bad door installation, something you're not likely to notice when you buy your house or have a new door installed. The installer needs to plumb a door so it opens and closes correctly, without leaving gaps.

That's why installing exterior doors is a job most homeowners should leave to the pros. Based on my handyman business experience, I'd guess 25 percent of exterior doors aren't plumb. Most homeowners don't realize they have a problem as they've learned to live with it. So if you still want to try installing your own door, please use a pre-hung door and verify it's plumb.

So what does it take to plumb a door? And why is this so challenging.

Learning How to Plumb a Door

Think about a letter you want to mail and finding the perfect envelope. Ideally there's extra space around the paper as you slide it into the envelope. If you're sloppy about folding and the paper doesn't quite fit, you can squish the paper. That works because the paper is less important than the message and neither the envelope or paper will get used more than once.

Doors get used a lot more than paper and envelopes. So it's critical that your door be installed properly inside it's envelope, which is known as a rough opening. Many door installation problems occur because the framing isn't right, e.g. the envelope isn't square. That's the first challenge for door and window installers. They need to make sure the rough opening is square before they can plumb a door.

So the first thing you want to understand are some of the potential challenges to fixing your existing door, or installing a new one.

• When bad framing leaves walls curved (see below), the door might be rotated (squished) to make it fit.
• When bad framing leaves walls tilted, so in order to plumb a door it will need to be on a different plane and therefore, can't be flush with the wall.
• When the floor underneath the door isn't level, the sill plate probably isn't level. The door installer has to make adjustments to plumb the door so it opens and closes properly.
• When the rough opening isn't square, the door installer may accidentally align the door with the rough opening so the door isn't plumb.

There are many other door problems too numerous to mention. Your hinge screws may be loose. The door might be warped. It happens quite often when doors aren't packaged and stored properly.

One of my handyman technicians installed a replacement door purchased by the homeowner. We didn't realize how warped it was until we laid it on top of a new door we bought. The center was bowed out more than an inch, which wasn't obvious until we laid it flat.

How to Plumb a Door

You know what it means to make a shelf on a wall level. It needs to be straight from side to side, and you use a level to make adjustments your eye can't see. To plumb a door, there are three dimensions to worry about. That's why installing doors and windows is so challenging.

1. Doors must be level from side to side. You use a level to verify (or adjust as needed) that a door is level.
2. Doors must also be plumb, meaning straight up and down like the walls of your home. You can use the same level, turned vertically, to make sure your door is plumb. You need to check the level on two sides of the door as it might be fine on one edge, and not the other
3. Doors must be flush with the wall with no rotation. This is critical for exterior doors because you don't want any gaps between the door and the door jamb, to allow conditioned (heated or cooled) air to escape from your house.

Resources If You Want to Install/Repair a Door

Most home professionals learn on the job. They learn the tricks of the trade by working alongside others who've done hundreds of door installations. As in any profession skills vary which is why we find so many door installation problems. If you want to try this yourself, here are the best resources I found while researching this article.

• The Family Handyman's Tips for Hanging Doors offers a comprehensive step-by-step overview, with lots of insider tips like using hidden screws and longer screws.
• EZ-Hang's article, Common Door Installation Problems and How to Fix Them covers lots of door problems from installation to things like squeaking or rattling doors.
• DIY Advice from Better Homes and Gardens, Troubleshooting Door Problems covers some problems that EZ-Hang didn't address.

Windows & Doors Start to FinishComplete Doors and WindowsComplete Guide to Doors & Windows

This article was meant to explain why installing or repairing an exterior door is so challenging. Hopefully you've learned enough to decide which way to proceed, doing it yourself or hiring a pro. Like many skills you have to decide if the time to learn to do it right makes sense. Would love to hear what you decided and why, to help me provide even better information in the future.

Wishing you luck with this and all your home projects.

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