Thank you to all of the sewers who have written asking about the sizing on my Raincoat and Jacket. I designed the raincoat as a very fitted jacket to be worn with lightweight clothing underneath.
I have gone back and reexamined our sizing and fit. What I have found is that your body measurements, including your bicep, cannot be any larger than the measurements listed in the Body Measurement Chart for that size.
One way to allow more room in the fit, especially when using the laminates, is to cut for a size larger than what is listed for your body measurements. This will increase the overall size for all areas of the jacket. NOTE: The laminated fabric does not "give" so it's extra important you figure out the appropriate size you need for adjustments.
To only make adjustments in the back and biceps area, I have written up some simple instructions to show you how to rework these areas. Please print this update and keep it with your original pattern.
Materials Needed if making pattern adjustments
 Rainy Days Raincoat Pattern Piece B Back Panel
 Rainy Days Raincoat Pattern Piece C Upper Sleeve
 2 large sheets of paper, a few inches larger than Pattern Piece C on all sides
Tools Needed
 Transparent tape
 Tape measure
 Quilting ruler (approx. 6" x 24")
 Pencil
 Paper scissors
NOTE: The Bicep area and Back area can be corrected separately. If you only need to correct the Bicep, you can start with Step 1. If you only need to correct the fit across the back, you can skip ahead to Step 4.
Step 1
ADJUSTING THE BICEP SIZE
A. First determine the difference between your bicep measurement and the one stated for your size on the Body Measurement Chart. With your arm in a bent position, use your tape measure to measure the widest part of your upper arm and then subtract the Chart measurement from this measurement. Write down this measurement as your Bicep Difference.
B. Next measure from your shoulder point down to the point where you measured your bicep. Record this measurement as your Bicep Length.
Step 2
DRAW YOUR GUIDELINES
A. Before you adjust for the bicep width, make sure to first make any overall length adjustments to both the Upper and Lower Sleeves.
B. On Piece C Upper Sleeve, find the existing mark at the top of the armhole curve. Using your ruler, draw a line from this mark down the entire length of the Sleeve to the bottom, keeping the ruler parallel to the lengthwise grain line. Label this line "A".
C. Start at the top of line A and measure down 1/2" plus your Bicep Length and make a mark.
D. Use your ruler and draw a new line at this mark, perpendicular to Line A extending across the sleeve width. Label this line "B".
Step 3
CONSTRUCT YOUR NEW PATTERN PIECE
A. Using your paper scissors, start at the bottom of Line A and cut all the way up until you are 1/8" from the very top of the Sleeve. Then cut along the separated Line B on both sides of line A until you are 1/8" from both sides of the Sleeve. You won't be cutting all the way through the edges, just enough to keep them still attached as one piece.
B. Gently slide a piece of paper under your cut Sleeve pattern. Tape the very top of Line A to the paper to hold it in place.
C. Keeping the hemlines at the bottom together, spread the pattern piece along Line A until the resulting gap at line B is equal to measurement you calculated in Step 1A.
D. The edges of line B on both sides will overlap each other and the hemline and top of the armhole lines will curve in slightly.
E. Now, measure the pattern overlap at line B on one side. This is the amount that needs to be added back to the length of the pattern both at the top of the sleeve and at the bottom of the hemline.
F. To do this use your ruler and pencil and first draw a straight line connecting the two sleeve seams at the hemline. This will straighten out your hemline.
G. Then, measure the distance between the new drawn hemline and the bottom of line A. Subtract this amount from the overlap at line B.
H. Take the difference between the Line B overlap and the measurement at the hemline and add it to the top of Line A at the sleeve cap.
I. Then blend the pattern edges back to meet the original curve.
Your bicep adjustments are now complete. Follow the original pattern instructions to complete your sleeve construction.
Step 4
DETERMINE YOUR NEEDED ADJUSTMENT FOR ACROSS THE BACK
A. First have a helper measure you across the fullest part of your back. This is from armpit crease to armpit crease. Then compare your measurement to the measurement for your size on the chart below. Subtract the pattern measurement from your measurement to find the Across Back difference.
B. Next divide this number by 2. The resulting number will be the amount you will need to add to the Back Panel in the following steps.
Step 5
DRAW YOUR GUIDELINES
A. On Pattern Piece B Back Panel, use your ruler and pencil to find and mark the center point of the shoulder edge. Draw a line straight down from this point, parallel to the lengthwise grain line, stopping about 1" below the armhole. Label this Line A.
B. Then measure and mark 1" down along the side seam edge. Draw a straight line horizontally out from this mark, perpendicular to the vertical line you drew from the shoulder, until it meets the vertical line. Label this Line B.
C. Measure and mark 3" down from the center of the shoulder along Line A. Draw a line from this mark to the armhole parallel to Line B. Label this line C.
Step 6
CONSTRUCT YOUR NEW PATTERN PIECE
A. Use your paper scissors and cut your pattern piece along Lines B and C. Then cut along line A between lines B and C and set this small section aside for the moment. Now, slide a piece of paper under this area and tape it in place.
B. With your ruler measure the amount you need to add to the Back from Line A along Lines B and C and make a mark on each line.
C. Now, place the small section of the Back Panel into its original place by sliding the piece along lines B and C until you reach the marks. Tape this piece in place.
D. Use your ruler and pencil and draw a line from the top of the side seam into the rest of the side seam below the separation point at Line B.
E. Then redraw the top of the armhole curve, blending a new line to the separation point at Line C.
Your adjustments are complete. You may now and follow the original pattern instructions to construct your Raincoat!
