
Sashing yardage
I need help figuring out the yardage that I will need for my sashing for my lap quilt. I am going to use a sage green sash and yellow cornerstones. My blocks are 12". I am guess I will use a 2" sash. It measures 44" wide X 58". Any suggestions that you can give me will be greatly appreciated.
http://i1056.photobucket.com/albums/...952c65a688.jpg

As it is shown in the photo with 4 stars across and 3 down ... I'll explain with those dimensions.
Note: This is just for sashing INSIDE the blocks ... does not include a border.
Also note: This is assuming that block size of 12" you gave is the FINISHED size, not the size the blocks are currently (before sashing).
Your going to need 6 2.5" X 2.5" blocks of yellow  a fat quarter is more than enough
You will need 17 2.5" X 12.5" strips of sage green for the sashing. 17 X 2.5 = 42.5 which is good because you can cut 2.5" strips across the WOF (so every strip will be with the length of the fabric). If your store only sells in 1/4 yard increments you will need 1/2 yard. If your store sells in 1/8 yard increments you can save some $$ and only buy 3/8 yard (13.5").
Now, math is not my best subject so you might want to wait until someone else chimes in and hopefully we have the same answer :)

2" sashing (finished?) so you plan to cut your strips 2 1/2" wide?
if so
you can cut 14 (2 1/2") strips from 1 yard of fabric if your fabric is 40" wide that gives you 560" of sashing strips
are you planning to put a 12" strip on each side of each block then a long strip across the bottom of the row? or 12" strips all the way around with corner stones? are your blocks 12" or 12 1/2"?
if putting a strip on all 4 sides of each block (12") you can surround 11 blocks with some left over
to figure out what you need decide on the cut width of your strips, divide that number into 36" (a yard of fabric) that lets you know how many strips you will get out of a yard
then you need to figure out how many sashing strips you need & how long they need to be divide the 40" width of fabric by the length of sashings you need to see how many you can cut out of the width
( you can cut 3  12 1/2" sashings out of 40" of fabric {37.5"}...

It also makes a difference if you want to cut your strips on the length of grain (parallel to the selvage) or cross grain (across the width of fabric)

Thank you so much for all the help. I'm amazed on the answers I get on this board.

I either follow a pattern or just guess and cut what I need. I have lots of fabrics to choose from. If I were buying fabric I would over buy just to make sure I have enough. That may be why I have ended up with so much fabric and so many scraps. There are lots of smart people on this board.