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| A Beautiful Pair of Custom Made Draperies |
I have been reading a lot of posts lately about just how this is supposed to be done and since I am finding a lot of inaccurate information out there, the thinking with this post is to make it easy to correct.
The formula below is for calculating yardage for custom quality draperies in 5 easy steps. In this post, the assumption is being made that the fabric does NOT have a pattern repeat. (I will explain how to adjust for repeating patterns in a future post) Because quality custom drapes will always be pattern matched if the fabric chosen will allow it.
STEP 1: MEASURE- Take measurements and determine the width and length of your completed drapery .(How to properly measure for draperies has been very well covered on web sites throughout the internet, but if I get any requests to cover the subject in greater detail, I will be happy to add a blog on that subject later as well.) For the purpose of this example, I am going to pretend that the finished drapery will cover 72" of the rod width, or it will be 72" wide, and the length will be 100". Your measures may be different, but they can be substituted for my 72 and 100 in the example. Once the measurements for your completed drapery have been determined, proceed on to the next step.
STEP 2: ADD TO LENGTH- Now, for the custom quality effects, we need to add to the length of our measurements. To the length, add 18". This allowance is for a 4" double hem at the bottom, and a double 4" turn around the buckram stiffener at the top, the other 2 inches are a working allowance for straightening the fabric as the drapes are made and/or for any material which may unravel while working on the drapes. This allowance is what is known in the profession as the "working allowance". Any custom treatment will have some sort of "add to length" working allowance which is required to properly construct the product and retain quality. Sometimes a drapery can be made with less than an 18" working allowance, but somewhere in the process, the quality will suffer, it might be done in such a way that it is not very noticeable, but common custom drapery making practice dictates the addition of 18". So now for our example, we will need 118" long cuts, pieces, or lengths of fabric to make our drapery. 100+18=118.
STEP 3: ADD TO WIDTH- To the width of the finished drapery we need to add for three things, the first is the "returns" of the drapery panels. The return is the part of the panel that covers the projection of the rod between the front of the drape and the wall. Drapery returns give the drapes a third dimension and without them there can be a bad looking gap that allows light to leak past the drape between the wall and the finished panel. If a return is not added it can also allow the lining material to show when viewed from the side, as seen in the example below. To alleviate these problems, custom draperies have a "return" which is
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| Draperies Without a Return |
typically 3-1/2 to 4 inches.
The other add to width consideration is the overlap addition. If the drapes will be a PAIR, they will typically overlap in the center where the two halves of the pair meet. This can be very little, 1-1/2 to 2 inches on a hand drawn drapery to about 4" on a typical utility type traverse rod. If the drapery you are making is a panel, (1 single drape drawing in 1 direction only) you do not need to concern yourself with the overlap. This addition applies to PAIRS only. So, if you are making a PANEL add 1 return dimension to the width, if it is a PAIR add two returns (1 for each panel of the pair), and add 1 overlap. So for the example which I am making a PAIR, the add to width looks like this: 72 + 4" overlap + 8" (2 returns)= 84"
The 3rd add to width consideration is a thing we call "ease" or "relax". This would be added to drapes which may spring back when drawn closed. This is of particular concern for drapes that will be hanging
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| Overlap Master on a Utility Type Traverse Rod |
on hand drawn rods with rings or on utility traverse rods where the fabric is particularly bulky or stiff. The amount of "ease" needed is not an exact science and an educated guess regarding your type of rod, type of pleat, and type of fabric will determine the amount of "ease" that should be added. If not enough is added, the drape may not overlap as it should and the fabric may gap open in the center, If too much is added, the drapery will have extra fabric between the pleats
when fully closed. It is best to remember that a little too much ease is better than not enough as the gap is much more noticeable than a little too much fabric between the pleats. In my example, I am assuming that a nice medium weight fabric is being use on a utility type traverse rod, so I am only adding 2" (about the minimum) of ease to my width. So now the FINISHED drapery WIDTH will be 72+4+8+2=86.
STEP 4: CALCULATE NUMBER OF WIDTHS NEEDED- Now we know we will want our drape pair to finish at 86". To calculate the number of widths,cuts, or fabric lengths we need to make our drapery, we must first add "fullness" to the finished width. Fullness is the extra fabric that will be taken up in the pleats when the drape is made. The more "fullness" a drapery has in it, the more luxuriously it will hang. This is critical to the custom appearance of the drapery. Not enough fullness will result in a drape that flattens out at the bottom and flares. Typical French pleated draperies require at least 250% fullness. Other pleat styles may require more or less fullness, but keep in mind, that less than 250% is often problematic if a full and luxurious drape of the fabric is desired. In my example, I am calculating the typical 250% addition for "fullness", so now the calculation looks like this 86 X 2.5=215" or 86 X 250%=215".To determine the number of fabric cuts you will need for this drapery, divide 215 by the width of the fabric being used (in my case 54") 215 divided by 54=3.98 widths (always round UP to the next full width). So I need 4 widths, or cuts of fabric for my drapery.
STEP 5: CALCULATE YARDAGE NEEDED- Going back to step 2, we know we need 118" long cuts, and from step 4 we know we need 4 of them. To calculate the yardage required we multiply 118 X 4 = 472" of fabric needed. Divide this by 36 (number of inches in a yard) so for this drapery pair 472 divided by 36 = 13.11 yards needed (round up to the nearest 1/4 yard just in case you need to work around a flaw), so 13.25 yards are needed to make a drape for this example window.
CONCLUSION: This really is a lot easier than it might sound. Practice these steps on your own windows and come back later if you choose to use a fabric with a pattern in it. I will talk more about calculating yardage for those and also maybe the mechanics of cutting and sewing the cuts together. Hope you will return for a future lesson.
