Method 1: Measuring the Sofa & Making a Cutting Layout.

Pros, Benefits of Making a Cutting Layout:

Since you make a layout in advance:

• You know how much fabric you will be using. You will also know much quicker if you need to get more fabric.
• Cutting the fabric is much less stressful. You know where to cut each piece. Your cutting layout is actually a cutting plan, and you just mark and cut the fabric following the plan.
• You can leave the old cover in place as you cut and sew the new cover. You can refer to the old cover at any time because it is still in place.
• If you want to, when you are ready to put the new cover on the sofa, you can just remove one piece at a time and put the new cover back on that same piece. The amount of time between when you take the old piece off and when you put the new cover on that piece isn't very long. So you should be better able to remember how it came off.
• Since you normally don't take apart the seams of the old cover, you have it to refer to if needed.

Cons, Disadvantages of Making a Cutting Layout:

On some pieces that need to be fitted, you cut the fabric twice, once from the layout rectangle size, and then cut it to shape.
It can be much more stressful to try to measure the sofa and to create a layout the first time.
Making a layout can be very tedious and take a lot of time, especially on your first time.

Measuring the Sofa

In order to make a cutting layout we need to measure every piece of fabric on every part of the sofa. (The actual pieces you measure will vary depending upon the style of your sofa.) Write down the widest point and the tallest point of every piece. Then add several inches to each measurement to allow for seam allowance and extra fabric to grab hold of to pull it. Measure all the welting. For a standard sofa, here is an example of what to measure (will vary with each sofa):

On the sofa deck (under the cushions) the fabric pieces that you need to measure are:
the Front Deck
Front Band
Front Band welting
On the arms measure
the Inside Arms*
Outside Arms
Arm Facing
Arm Facing Welting
On the backrest, measure
the Inside Back*
the Banding
the Banding Welting (add about 20 inches to what shows. This welting needs to be long enough to stick through the frame slots and put through to the outside. More about this later.)
the Outside Back
The Outside Back Welting
On the Cushions measure
the Cushion Faces (top & bottom),
Boxing
Welting
Zipper pieces
There may also be other pieces to measure that are not listed here.

*The inside arms and the inside back need special consideration. First you need to determine whether or not you will be using a stretcher cloth at the bottom of these. If so, then you will add about 3 or 4 inches at the bottom of each of these

Planning Your Cuts

Making a Cutting Layout

Here are three different ways to do a planned layout. For each of the pattern pieces just make a rectangle. Don't worry about shapes or darts at this point.

Pencil and paper:

Use a large piece of paper (butcher paper, etc.) and draw out a large rectangle, to scale, to represent the fabric size. Then lightly pencil in the various pattern sizes, with ID marks and measurements, in the middle of the large rectangle. Erase and rearrange as necessary to get the best use of the fabric.

Graph paper:

Scale down your measurements so that one inch equals one square (or something similar). Tape together enough sheets of graph paper to the size of your fabric. Lay the graph paper on a large flat piece of cardboard or a corkboard and use thumbtacks to attach the graph paper. You can lay board flat or put it up on the wall.  Then, for each fabric piece, Draw a dark line around the edges of each pattern piece, following the lines of the graph paper. to mark each piece to scale. As you cut each piece, mark it (i.e. IB for inside back, IA for Inside arm, OA for outside arm, etc.). Also mark the L  X  W size on each piece. When you have all the patterns cut. rearrange then on the fabric graph paper base to get the best fit. As put everything in place, use thumbtacks to hold the small rectangles of graph paper onto the large piece of graph paper. Rearrange the cut pieces to get the best use of fabric.

Drawing or CAD software:

This is the method that I use. It is the hardest to learn, but is the easiest and most efficient to do once you have master it. It works similar to the graph paper, except on the computer. You draw one large rectangle to represent the roll of fabric. Then, using the measures from your sofa, you make rectangles to represent the cut sizes of the different parts of the sofa. Attach dimension lines to each rectangle, and label the rectangle for each sofa part (i.e. IA = Inside Arm, IB = Inside Back, etc.) Arrange the labled rectangles on top of the large rectangle to get the best use of the fabric. Then print out the finished drawing and use as a guide to mark and cut the fabric. As you cut each piece, transfer the identification marks from the drawing to the back of the fabric.

Cutting The Fabric

Assuming that you are using a plain fabric, you can railroad the fabric (cut from the side). Since you (presumably) have already did a fabric layout, just mark and cut the fabric following the your plan. You can use a carpenter's framing square to square up the fabric.

As you cut out each piece of fabric, draw a line along the top edge to identify which is the top of the fabric.Also mark an id mark on the back side of each piece. When marking the back, careful to use a marker that won't bleed through the fabric.

Fitting The Cover

You can either fit each piece of the new cover while the old cover is still attached to the frame (which is easier) OR you can fit each piece (after the cover has been removed  and the frame has been prepared for covering) as you are ready to attach it to the frame. For this tutorial, we will assume that you will use the first method.a ...

For any pieces that need to cut to shape, lay the precut pieces upside down on the corresponding pieces on the old cover (which is still on the sofa), check all around the edges that everything has enough for at least a 1/2" seam allowance. and pin it in place. Once the new fabric is anchored in place with the pins, use a marker to draw on the back side of the new fabric along the seams of the old fabric. Wherever there aren't any seams, push the fabric into the crevaces so the fold makes a right angle. Wherever appropriate, draw a line around those fold lines. Then, before cutting it, add a 1/2" seam allowances to all seam areas

a If you will be doing any rebuilding or repadding of the frame, then we'd recommend you use the second method.

Sewing The Cover

If the inside back has a cording around the front, then when you sew the cording onto the IB piece, center the cording so that the cording will protrude about 5-10 inches past the bottom edge of the IB. You will need this extra cording sticking out when you attach the IB to the frame.

Removing the Old Cover

When you have all the new cover sewn, take off the old cover. For instructions, see Method 2, Removing The Old Cover.

You have a choice. You can either take off the entire old cover at one time, or you can take only as much apart as needed at one time.