Carpet is specified less frequently in multifamily residential units than it was a decade ago, largely displaced by LVP as the primary hard surface residential specification. But carpet remains the dominant specification in multifamily corridors, stair landings, and amenity spaces across the western US market, and it is still specified in bedrooms on a meaningful percentage of Class A and Class B multifamily projects where developers are competing on acoustic performance or on a warmer material aesthetic.

When carpet is in the specification, the installation requirements are specific and the failure modes are visible. A seam placed in the wrong location produces a visible line in the middle of a room. Incorrect nap direction makes a corridor look inconsistent from one section to the next. Inadequate stretch produces ripples that appear after move-in when humidity changes. A transition to LVP at a bedroom threshold that does not account for the height differential between the two products produces a trip hazard or a visible gap.

These problems are not discovered at installation. They are set up before installation, by decisions made at seam placement planning, at substrate preparation, and at transition detailing. This article covers what to confirm about a carpet installation subcontractor before mobilization and what the specific technical requirements are for carpet on multifamily projects.

Product specification for multifamily carpet

Carpet for multifamily residential applications is specified by face fiber, construction, face weight, and density. The combination of these four elements determines durability, appearance retention, and ease of maintenance over the residency cycle.

Face fiber, nylon versus polyester versus polypropylene. Nylon is more durable than polyester under repeated traffic and cleans more effectively after staining. Polyester has improved significantly in recent product generations and offers good value at a lower material cost, making it the common specification for workforce and market-rate residential. Polypropylene (olefin) is generally specified in commercial applications rather than residential because its lower melting point makes it susceptible to pile crushing under furniture.

Face weight and density. Face weight is the weight of pile fiber per square yard. Density accounts for both face weight and pile height. Higher density produces better appearance retention under foot traffic. For Class B multifamily, 32 to 40 ounce face weight with a density of 3,000 or above is a reasonable specification. Class A applications typically specify 40 ounce and above.

Construction type. Cut pile, including saxony, textured, and frieze, is the most common residential specification. Loop pile is specified in corridors and amenity spaces where durability is prioritized over softness. Cut-loop offers a pattern option but requires seams at points where the pattern aligns correctly.

Padding. Carpet requires padding that meets the manufacturer’s installation requirements. For multifamily projects with IIC and STC acoustic requirements, the padding specification is part of the acoustic assembly and must be confirmed against the project’s acoustic specifications.

Seam placement planning

Seam placement is the most consequential pre-installation decision in a carpet installation. A seam in the wrong location is visible, distracting, and permanent, it cannot be corrected without replacing the carpet.

On multifamily projects, seam placement planning must account for the width of the carpet roll (typically 12 feet), the dimensions of each room, the location of furniture and fixtures that will reduce traffic over the seam area, and the direction of light relative to the seam. Seams are most visible when they run perpendicular to the primary light source, windows and overhead fixtures, and least visible when they run parallel to it.

A qualified carpet installation subcontractor will submit a seam placement plan for each unit type before cutting begins. The plan identifies where each seam will fall in each room relative to the room dimensions, the furniture plan, and the light sources. This plan should be reviewed and approved by the GC before the carpet is cut. Once a carpet roll is cut, the seam placement is committed.

Nap direction. Carpet pile has a directional orientation. When carpet is installed across a large area, a corridor, a large living space, all sections must be installed with the pile running in the same direction. Sections installed with the pile running in opposite directions will appear to be two different colors when viewed from a distance, even if they are the same product and the same dye lot.

For corridors, the standard nap direction is with the pile running toward the primary entrance so that the pile lays toward the viewer as they walk in. Confirm this convention with the carpet sub before installation and confirm that the sub is managing nap direction consistently across all sections on each floor.

Substrate requirements for carpet installation

Carpet is more tolerant of substrate irregularities than LVP or tile, but it is not infinitely forgiving. Substrate defects that are large enough, high spots, low spots, debris, will telegraph through the carpet and padding and be visible or tactile after installation.

The substrate under carpet should be clean, dry, and free of debris before carpet is installed. Concrete substrate should be swept and inspected for high points or ridges that will telegraph. High points above 3/16 inch relative to the adjacent area should be ground down before installation. Wood subfloor substrate should be checked for squeaks, loose fasteners, and high nail heads, all of which will be audible or tactile after installation.

Moisture in the substrate is a concern for carpet in multifamily construction, particularly in areas adjacent to wet areas or at grade level. Confirm moisture conditions in areas adjacent to wet areas or at grade level.

Transition and threshold planning

Carpet transitions at thresholds, to LVP at bathroom entries, to tile at lobby entries, to hard surface at elevator landings, require transition strips that accommodate the height differential between the two products. The type of transition strip, the height differential it can accommodate, and the visual appearance of the transition all need to be confirmed before either product is installed.

On multifamily projects, the transition from bedroom carpet to LVP at the threshold is a common coordination point between the flooring sub and the cabinet sub, because the threshold is often located directly at the doorway where the door casing meets the floor. The transition strip needs to be planned relative to the door casing before flooring is installed so that the casing can be notched correctly.

Corridor carpet at elevator landings typically transitions to tile or LVP in the elevator cab. The elevator cab flooring is typically not part of the interior finishes sub’s scope, but the transition strip at the cab entry is. Confirm scope responsibility for the transition strip at each elevator landing before installation.

How Innergy handles carpet installation on multifamily projects

Innergy covers broadloom and carpet tile on multifamily projects as part of our Division 9 scope. Before installation, we submit a seam placement plan for each unit type, confirm nap direction for corridors, and document substrate conditions. On full-package projects, we coordinate transition strip height with our own LVP scope, eliminating the cross-sub coordination that creates threshold problems. For carpet as a standalone scope or as part of a full seven-division package, contact us and we respond within one business day.