Guide · For the trade
Where to put carpet seams: reading and approving the seam diagram
Where to put carpet seams is decided on paper before the roll is cut: seams run the length of the room and with the main traffic, parallel to the light from the biggest window, away from doorways and pivot points, under furniture where there is any, and never across the width of a hall or on a stair. The seam diagram is the drawing that shows every seam, the pile direction and the cut list for each roll, and the designer approves it before the carpet is ordered, because the diagram sets the yardage.
This guide is for the designer or the junior who has just been sent a seam diagram to sign. It covers the rules of placement in order, how roll width drives the diagram, the rooms that need a judgment call, what the drawing has to show, and the questions clients ask. Why a seam shows is in the carpet seams guide; the arithmetic is in the carpet yardage guide. This one is about the layout.
The placement rules, in order
When two conflict, the higher one wins.
- Pile runs one direction through every connected space, usually toward the main entry so the carpet reads darker and fuller from the door. Two pieces with the pile running opposite ways show as a color change no matter how well the seam is made.
- Seams run with the length of the room and with the traffic, not across it. A seam walked along is invisible; a seam walked across is crossed a hundred times a day and wears open.
- Seams run parallel to the dominant light source; light raking across a seam throws a shadow along it.
- No seam through a doorway in the direction of travel, and none within 6 inches of a pivot point such as a door swing or the foot of a stair. A seam between two rooms sits under the closed door, centered on the jamb.
- Seams go where furniture will stand: under the bed, under the sofa, along the dresser. The furniture plan is part of the diagram, which is why the designer, not the installer, places them.
- Cross seams are kept to the minimum and placed in closets, under beds or at the far end of a room, and fill pieces are at least 12 inches wide and never in traffic.
How roll width decides the diagram
Most broadloom is 12 feet wide; much woven wool and patterned goods comes at 13 feet 2 inches (4 meters), and a few tufted lines run 15 feet. Any room wider than the roll needs a seam, and the question is only where. A 14 by 18 foot living room in 12 foot goods takes a 2 foot fill along one long wall, placed on the sofa side with the pile direction carried through. The pattern repeat guide covers the extra allowance a pattern adds, since every seam on a pattern has to land on a repeat.
| Room | 12 ft roll | 13 ft 2 in roll | 15 ft roll |
|---|---|---|---|
| 12 by 14 bedroom | No seam, run the 14 ft way | No seam | No seam |
| 13 by 16 bedroom | One seam, 1 ft fill along the dresser wall | No seam, run the 16 ft way | No seam |
| 14 by 18 living room | One seam, 2 ft fill under the sofa | One seam, 10 in fill | No seam |
| 16 by 20 great room | One seam, 4 ft fill; pile toward the entry | One seam, 3 ft fill | One seam, 1 ft fill |
| 4 by 30 hall | No cross seam; cut lengthwise from a 30 ft drop, 8 ft wide offcut for closets and fills | Same | Same |
The hall is the room that tempts installers into cross seams to save yardage. Do not accept one; a hall is cut from one long drop.
The rooms that always need a decision
A hall that meets a stair carries the carpet onto the landing in one piece, with the seam at the first riser or at the landing nosing if it takes a runner; the stair runner installation guide has that detail. An L-shaped room takes its seam at the inside corner, running with the longer leg. A bay or a fireplace projection has the fill behind it, out of the sightline from the door. A long corridor takes its seams at the cross corridors, under the doors. Closets are the one place a cross seam and a change of pile direction are acceptable.
What the seam diagram has to show
A diagram the designer can approve has the floor plan with the furniture, every seam drawn and numbered, an arrow for pile direction in every room, a cut list giving each piece its length from the roll and its room, the roll width assumed, the total linear feet and the waste percentage, and every transition to a hard floor. A patterned carpet also shows the repeat and where the pattern starts in the main room. The installer or our estimator draws it; the designer checks pile direction, seam placement against the furniture and the light, and the fill widths, then signs it. Once signed, the order is placed to it, and a change afterward is a new cut list and sometimes a longer roll.
How Interiors handles the diagram
Send us the plan with the furniture, windows and doors on it, and the style you are specifying so we know the width. Our estimator returns a seam diagram and the yardage within a day or two, placed to the rules above, for you to approve before the order goes to the mill. The approved diagram travels with the material to the installer in the client's city, so the crew lays out to the drawing rather than to habit.
Questions designers ask
Where should carpet seams go in a room?
With the length of the room and the traffic, parallel to the main window, away from doorways and pivot points, and under furniture. Between rooms, the seam sits under the closed door. The pile runs the same way through every connected space, usually toward the entry.
How can seams be hidden once the carpet is down?
A seam on a cut pile disappears when the installer seals both cut edges, runs the seaming iron slowly, rolls the seam while the tape is hot and then stretches across it; a textured or heathered color helps, and a loop or a pattern is harder. A seam that shows later is usually peaking from over-stretching or an unsealed edge.
Can carpet seams be repaired?
Yes. An open seam is re-sealed and re-taped with a seaming iron; a frayed seam in a cut pile is trimmed, re-sealed and re-rolled; a seam worn through in traffic is cut out and a new piece set in from attic stock of the same lot. Repairs at a doorway or a pivot point are the hardest, which is why the diagram keeps seams away from them.
Which side of the carpet pad faces up?
The smooth, printed or film-laminated side faces up, toward the carpet, so the backing slides over it during the stretch; the rougher side faces the subfloor. Pad seams are taped and never fall directly under a carpet seam.
Is wall-to-wall carpet still being specified?
Yes, especially in bedrooms, media rooms, stairs and halls, where its acoustics and warmth have no substitute. The seam diagram separates a carpet that looks woven in place from one that looks pieced; the wall-to-wall carpet guide covers the rest of the case.
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