How to Measure for a New Exterior Door

There are a few concepts that will naturally be vital when installing any kind of new exterior door on your property, and proper measurement of the door and door space will definitely be on any such list. How should exterior door measurements be taken, and why is this an important area for any kind of door replacement or installation?

At Rocky Mountain Windows & Doors, we’re here to help clients around Utah with a huge range of exterior doors and door services, including front doors, entry doors, and various other custom doors for you to choose from. Here are some basics on why the proper measurements for any door installation are vital, the risks present if improper measurements are taken, and the basic process for measuring a door – whether on your own or with help from our professionals wherever necessary.

Measure for a New Exterior Door

Why Proper Measurements Are Key

Firstly, let’s start with the simple fact that every home is unique. Even if your home may look similar to others on the street, houses are built with slight differences in shape, size and even terrain.

This is why proper measurements are crucial for any new exterior door installation. You cannot simply grab a standard-sized door from the store and expect it to fit perfectly – you need to take precise measurements in order to get an accurate fit.

Risks of Improper Measurements

If improper measurements are taken, this can lead to various issues with your exterior door. These include:

  • Oversized door: Doors that are too big for the space will not open or close properly, and may even get stuck. This can also cause damage to other parts of your home, such as walls or flooring.
  • Undersized door: On the other hand, a door that is too small for the space will leave gaps around the edges and compromise insulation. It may also be easier for intruders to break in through these gaps.
  • Uneven door: If measurements are not taken evenly, this can result in a crooked door that does not sit properly within the frame and is difficult to open or close.
  • Possible cost and liability issues: Improperly sized doors may need to be replaced, which can result in added costs and wasted time. It could also lead to potential legal issues if the improper door is a safety hazard.

Our next several sections will go over the basic process for measuring for a new exterior door – and our team is happy to help with any of these areas if needed.

Old Door Measurements

In cases where you’ll be replacing an existing door, start by measuring the old door itself. If the original door was properly installed and fits well, it can be a helpful guide for finding the right size for your new one.

Measure across the top of your old door from one end to the other, then measure down one side from top to bottom. Generally speaking, you can feel comfortable rounding up to full inches for these measurements – if a measurement is 35.75 inches, for instance, round up to 36.

Rough Opening Measurements

In cases where you do not have an existing door or are replacing the entire frame, you’ll need to measure the rough opening (RO). This means measuring from stud to stud as well as from top to bottom of the intended doorway.

Start by measuring horizontally across the top of the RO from one stud to another, then vertically from the bottom of this measurement up to the bottom side of the header. Again, you can round up if necessary.

Jamb Width

When we talk about jamb width, we’re referring to the width of the door frame. This is one area where we recommend consulting with our professionals, as there are several factors that can go into the jamb width determination.

Generally, however, these measurements will be taken from the backside of the interior trim to the backside of the exterior trim. This will allow you to specify a door with the proper jamb width for your space.

Threshold Measurements

Threshold measurements will refer to the bottom section of the exterior door frame. This should be measured from one side to another, just like when measuring the top or sides of the door itself.

Like with other door measurements, it’s generally best to round up if needed.

Exterior Opening

Finally, you’ll need to measure to the outsides of the exterior casing, then from the bottom of the sill to the top of the trim. From here, these numbers can be compared to the door you’re interested in to determine if it will be a good fit.

If the door is too small for your opening, you have some options. You could add a piece of decorative molding that’s roughly the size of the gap, allowing you to fit a smaller door in the space. In other cases, you could fill gaps with additional strips of wood (with professional help if needed). However, in many cases it’s simpler to just find a new door – which will also always be the proper approach if it turns out that your door is too large for the opening.

Utilize Professionals if You’re Uncertain

We recognize that certain elements of the process we’ve gone over here might be intimidating for some homeowners. It’s vital not to let your pride or ego get in the way of a proper exterior door installation, however – and our team is here to help.

We’re happy to offer full assistance with any or all of these measurements, plus any other areas you might be uncertain about during the process. Call today to learn more about our services or schedule an appointment for your project!

Proper measurement is key for any exterior door installation. It ensures that the door fits properly and functions effectively. As discussed, there are several risks associated with improper measurements, such as damage to your home or potential legal issues. That’s why it’s important to follow the proper process for measuring a door – whether on your own or with help from professionals.

And at Rocky Mountain Windows & Doors, our team is always happy to assist with any step of the door installation process, including taking accurate measurements. Contact us today for all your exterior door, interior door and window needs around Utah!