How to Measure a Storm Door

Posted by John Whalen on

How to measure a storm door

OK, this is a pretty broad area.  Lets start with measuring a storm door, being as this is the main product on this site. 

First thing you have to do when measuring a storm door is to determine how the door will be mounted.  There are many of types of installs that I’ve run across in the last 39 years and the biggest factor is…the age of the home.

Most homes built in the mid-fourties to date will probably be somewhat standard in the way they’re mounted.  Probably two different types in this date range:

  1. Will be on brick molding (as it’s called)
  2. Will be on some form of “1 x” material – and I’m talking about the framing on the outside of the door.

OK…so you want to mount a storm door on these frames.  A brick-molding fit is the easiest of the two.  Why?…well that’s simple…most storm doors have what they call Z-bar frames that require a 1″ deep frame to mount without any form of build-out.

Consider that brick-molding is usually (1″to 1-1/8″ deep x 2″ to 2-1/4″wide) in size.  Perfect for most frames that come with your storm door.  Measure width first: 30, 32, 36 (standard – another advantage of newer homes) x 80 (more than likely).  If you take the tape measure and measure from inside the brick-mold on the right of the door to inside the brick-mold on the left, then from the inside top down to the threshold (stone, aluminum, or wood) of the door, it should be in the range of the size I noted earlier.  If its 1/8 to 1/4 smaller it will still work well or up-to 1″ bigger (say 33 x 81-1/2) you’re still OK, but the bigger size may have to be built-in to the 32″ x 80″ range (in this example). 

So what about on a 1″ x 4, 5 or 6″ framing???  As far as measuring goes, it’s the same as stated above.  You may know this type of frame isn’t a true 1″ deep, its 3/4″ deep.  Remember that the storm door frame requires 1″.   Conclusion: its going to need to be built-up 1/4″ all around the perimeter of the opening.

Back in the seventies we used a product called vinyl build out…if you asked for that now, people would give you a weird look like…what are you talking about?  Now-a-days 1/4″ x 1″ lattice will work well.  Don’t nail it on…use the screws supplied with the frame (Z-bar) to secure after the level location of the door is established.  This way the wood sits neatly under the Z-bar as opposed to sticking out unevenly in plain sight. We will go over this technique when we talk about installing a storm door.

For the most part all doors will be measured similar to the brick-mold measurements described above.  What your trying to figure when measuring is the opening size that will house the slab and the Z-bar frame of the storm door. The difference comes in the way a door is mounted.  A- Z-Bar frame, a cut-down Z-Bar frame, a expander hinge install, undersized wood frame install, or other method of mounting.   There are times when rather then ordering a custom sized door you have to alter the frame to fit the stock size storm door.  There are techniques that range from controlled chiseling to complete re-frame.  We’ll discuss those later in our storm door install instructions. 

Some storm-doors require that you state what side of the door the hinge will be on.  This is determined on storm-doors by standing on the outside of the door looking in.  Which side will the hinge be on…right or left.  Be sure to write width first always then height size.  The finished size would be something like “32 x 80 HL” or Hinge Left.  I’ll get more into sizing specifics when we discuss installing a storm door. 

One last note, the actual storm door will be about 1/2″ to 3/4″ smaller then the size you measured.  This is normal and done so that the Z-bars will have clearance to fit and be adjusted.  Then to finish the install, the lower expander rail with the rubber of brush weather-stripping is lowered and secured.

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