Square-in-Square Block Tutorial
For PERFECT Square-in-Square Blocks every time!!
The Square-in-Square Block is a quick and easy traditional quilt block. It is commonly used as a transition block, whether between two blocks in a quilt, or as a way to create some negative space in a repetitive block pattern. It is also a block that can create a bonus HST block if planned correctly!
The Square-in-Square Block is very straight forward, but even so, there are a few different methods out there for this block. I think that I have tried every single method, and the Type A quilter that I am, I wasn’t happy with the amount of fabric distortion that happens in many of the methods. There are a few places where the block can go wrong because working with fabric on the bias always runs the risk of your square getting out of shape. Also, sewing from corner to corner can sometimes leave your finished intersection with an undesirable edge.
Read on for step-by-step instructions and tips to get a perfect Square-in-Square every time!
Gather your tools ahead of time so that when you begin working, you can dive right in!
To make the Square-in-Square Block, you will need the following tools:
- Rotary Cutter, Acrylic Ruler, and Self-Healing Mat
- Fabric Pencil
- Ironing Board and Iron
- Spray Starch (optional)
- Marking Ruler (optional)
You will also need the following fabric:
- Background Square
- Corner Squares
In order to calculate the size of your squares, begin with the size of your finished block. In this tutorial, my finished block is 8″. From there, you can find the:
- Background square by adding 1/2″ for seam allowances. My background square is cut at 8.5″.
- Corner squares (4) by diving the finished block size in half. My finished block size in this tutorial is 8″, so I get 4″ when I divide that in half.
- Take the number you just calculated in Step 2, and add 1/2″ for seam allowance. My number was 4″, so my corner squares are cut at 4.5″.
Prepare your Squares
Before you begin sewing, you need to prepare your corner squares. In order to do this, take you marking ruler and lay it on the wrong side (WS) of (1) of your corner squares. Use your fabric pencil to make a line from corner to corner.
Repeat on your remaining (3) corner squares.
This step is repetitive, and time consuming, but it is your first step to success. Every step after this one counts on an accurate line drawn here. Take your time to make sure that your pencil mark starts right at one corner and goes directly to the opposite corner. You will be using this line to sew an accurate seam, so put in the time.
I find that using a nice sharp pencil helps me get an accurate, thin line.
Once your corner squares are prepared, you are ready to sew.
Place two corner squares cady-corner to one another on your background square. The lines that you drew when you were preparing your corner squares should be touching the edges of your background square.
You should have the right-sides of the fabric facing each other with the corner squares on top of the background square, making sure the wrong side of the corner squares are facing up.
Pin in place to help keep your fabric from shifting, if needed.
In the above picture, you can see that I have drawn my lines corner to corner. With this particular method, we are going to be pressing our fabric to the side, and this creates a little bit of a ledge. This ledge is called “loft.”
In order to offset the loft, we are going to sew our seam just a threads width to the outside of the line we drew when we prepared our corner squares. I know what you are thinking. A threads width? Are you kidding me? I promise you, this is going to be the difference between, “uuuugh, why can’t I get a crisp, clean edge?!” and “Oh my gosh. I nailed it AGAIN!”
So, to clarify, our line is supposed to be going from exactly one corner to the other corner. If we have properly bisected those two corners, than we can go ahead and sew our first seam just to the outside of this line. The outside being the side of the line that is closest to the outside corner of the squares, not the side of the line that is closer to the middle of the squares.
Press your Corner Squares
Typically this is the time that we get ready to trim our squares, but we’re going to be little rebels and press first. Pressing first has two major advantages:
- It gives your corner square a little more structure, allowing you the ability to find and press the seam into a nice crisp line.
- It supports your corner square so that when you press the square in place, there is lower chance of it getting ironed out of shape.
If you have starch on hand, I would recommend lightly starching your squares first.
Once you have lightly misted with starch, give your seam a press straight down to set the seam. Setting the seam will push the thread into the fabric and will reduce the amount of loft created when we press to the side in the next step. In the next photo, I have already set my seam and I am finding my seam line.
Use the nose of your iron to gently push your fabric all the way to the seam as seen in the photo above. It is important to make sure that when we press, we are pressing a true seam, and not creating a false fold. Once our hot hot iron has nudged and set the true seam, we can then press the rest of the corner square.
It is really important to note that I am not going to push my iron from the seam out to the corner because this will distort my fabric due to the bias of the fabric weave. Instead, nudge your iron along the seam line, lift your iron to reposition it, and then press down on the corner to get that corner set!
Now that your first corner is all set, repeat for the other corner square, nudging the fabric to the seam (seen above) and then pressing to set.
Now we are ready to move to the cutting mat. Go ahead and lift one of the corners that you’ve pressed back towards the center, revealing the two layers of fabric underneath.
Lay your acrylic ruler on your corner square, lining up the 1/4″ mark of the ruler with the seam. This will allow you to cut a 1/4″ seam for the corner of the block!
Cut along your ruler with your rotary cutter and
remove the two layers of fabric.
Check out the waste that is created from trimming the block. Do you see what I see? YES! Half-square triangle potential! From every Square-in-Square block you make, you will be able to create (4) HSTs. All you need to do before you cut is:
- Draw a line 1/2″ away from the seam that you sewed in the previous sewing step.
- Sew a seam along the line you just drew.
Once your second seam is sewn, you can trim the corner square as described above, lining up the 1/4″ mark on your ruler with the first seam. When measuring 1/4″ away from the first seam you sewed, you will also be 1/4″ away from the second seam you sewed! YES! Bonus HST in the bank!
Continue with the next corner square…
Repeat for the other corner, laying the top layer back down towards the center of your block,
align the 1/4″ mark of your ruler with the seam you sewed previously,
and trim! You should also probably practice better trimming habits than me. In an effort to get the above picture, I had to turn into a pretzel. HA!
At this point, you are able to repeat the steps that you took for the first two corner blocks with the remaining two corner blocks.
Begin by opening up the two corner units that you have already sewn and pressed. They really should lay nice and flat again since you already went in with a hot iron before you trimmed, but if you need to, give another press.
Lay your remaining (2) corner squares down on your background square right sides together. You will notice that the lines you drew earlier will once again be touching the sides of the background square, they will not be passing through the center of the background square. You will also notice that the corners of the corner squares with the pencil marks will overlap the corner squares that you have already sewn. This is a good thing! We want the remaining (2) corner squares to be laying over the corner squares that are already sewn.
Once again, make sure that you are sewing your seam just outside the pencil mark, towards the outside corner of the square. Once again, this is going to compensate for the ridge/loft that is created by pressing the fabric to the side.
Once your seams are sewn (you can see in the picture above how my bottom seam is on the outside of the pencil line), starch again if desired.
Again, set your seam by pressing your iron straight down on the seam you sewed before you move your fabric. This will push the thread into the fabric and help reduce loft.
Nudge the fabric to the seam line with the nose of your iron, and once you have pressed it over the true seam line, lift your iron and press straight down on the corner square. You’ve made it this far, don’t push that fabric out of shape by “ironing” instead of “pressing” now!
Repeat on your last corner square, nudging the fabric along the seam line once again, and then pressing the corner square down to set it in place.
Lay the squares that you just ironed back flat again, and trim. Line up the 1/4″ mark on your ruler with the seam that is running corner to corner on the corner square and trim!
Remove the scrap (also known as BONUS HST if you took the proper steps as outlined earlier. I did not. Now I have extra work. BOO.)…
and move your fabric back out.
You know just have your final corner to cut. Lay the corner square flat, line up the 1/4″ mark of the ruler with the seam, trim, and remove excess fabric.
Admire your work
To recap, there are a few things that you can do to make sure that you get really gorgeous intersections on your Square-in-Square blocks while still maintaining the shape of the block:
- Pay close attention to how you are drawing your lines on your corner squares. Make sure you are using a sharpened thin fabric pencil, and mark it right on the corner.
- When using this pencil marking as a guide, sew your seam just to the outside of it to compensate for loft.
- Press first, trim second. This will allow you to be nice and firm with nudging the fabric over the seam.
- Starch. This will lock the weave together to help keep your fabric keep its shape.
- PRESS, DON’T IRON
- Make sure that you are using pressure when you are nudging the fabric over the seam.
- Once you find the seam, STOP NUDGING. Pick up your iron and set that corner square in place by pushing straight down.
- Trim after pressing to remove bulk.
Oh you guys. CHECK OUT THAT INTERSECTION. You know what that will become? Yes. A lovely, beautiful point when I join my blocks.
I will be posting a video tutorial on my YouTube channel soon, and in that video I hold up a ruler to show the distance from that point to the edge of the block. It is slightly MORE than 1/4″ which is what I want. This will help compensate for the bulk in the seam and any pressing when I start to assemble this block in future steps.
Give yourself two thumbs up and a pat on the back! Your Square-in-Square looks beautiful, and you are one step closer to successfully sewing up patterns that call for the Square-in-Square! As always, feel free to post any questions in the comments, or hunt me down on IG, Facebook, and on the Tea & Brie Community Page!