1. Measure Your Space
Record the length, width,and height of the room where the sectional sofa will sit. If you're considering placing the sofa in front of windows, make sure to measure the height of the window sill. The sofa back typically should not extend higher than the sill.
2. Tape The Area
Mark off the area on the floor with masking or painter's tape. Taping off the space will allow you to visualize how much space the sofa will occupy in the room. Pay attention to placement and scale. Sectional sofas are large so spend time assessing how the décor in the rest of the room will fit. You may need to remove something or rearrange furniture to get to a design that works. Remember to allow walking space for around the sofa and coffee table.
3. Measure For Delivery
Measure the hallways and all other areas through which the sofa will be carried when it is delivered. Note the narrowest areas you'll need to pass and keep those measurements on hand when shopping. In tight areas sometimes the sofa legs can be removed to fit through.
You may want to move your sofa at some point. So before you buy, measure for multiple furniture arrangements to ensure the L-shape of the sectional will fit.