How to Measure Rough Openings for Steel Casement Windows How to Measure Rough Openings for Steel Casement Windows

What You'll Need
Tape measure or ruler
Ladder or step stool
Paper and pencil

Steel casement windows are found often in mobile homes and recreational vehicles. These windows are designed as a single window and screen unit that has a crank attached to open the window out at an angle. As with any window installation, making sure that the opening is measured properly to pick the proper size of casement window.

Step 1: Enclosure for Casement Window

When measuring the hole for a casement window, it is necessary to accommodate the lip that the window is going to be attached to in the wall. If you do not have the lip already installed then it should be put in place before measuring for the window. In the event that you do not have the mounting assembly in hand then measure considering the lip is in place, and subtract 1/4 inch both across and from top to bottom. This will give you the proper measurement for the window insert. On the tape measure, begin your measures with the 1 inch mark instead of the edge of the tape to get accurate sizes. 

Step 2: If Using a Ruler or Yard Stick

When using a ruler or a yard stick the best method to measure the opening would be to begin with inch 1 instead of the edge of the measuring device. In this way you will get a more accurate measurement because many times the edge of the ruler has around 1/64 less to 1/8 inch more than the actual inch measure, which will affect the measurements of your space. If it is possible, get 2 different people to measure the opening to get a consensus.  Measure twice, and cut once will give you more accurate measurements and give you less grief.

Step 3: Accommodations

When you are measuring for a steel casement window you need to ensure that your measurements include the installation of the crank for the window. Many window assemblies are complete with a small window sill. If you are going to install a new casement window where one did not exist then the window sill should be removed before the measurements are done. The window sill will take up space that needs to be considered. Also any frames that are installed may need to also be considered in the measurements to make sure that they do not interfere with the operation of the window opening. Because of the logistics of the window opening outward instead of sliding up or across the additional space taken by an open casement window needs to be thought about before the measurements begin.

Step 4: Insurance

As mentioned before it is always a good idea to measure 2 times, and if you have a friend or family member available then you should measure once and they should measure once, then compare the measurements. In this way you will ensure that your sizes are more accurate giving you less trouble when you've ordered and are ready to install your casement windows.

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