Hardwood Flooring Installation in Pasadena, CA: From Subfloor Preparation to Beautiful New Floors

Beautiful hardwood floors start with what you never see. On this Pasadena project, our installation team worked through several stages before and during the hardwood installation: preparing the plywood subfloor, filling uneven areas with leveling compound where they needed it, staging the flooring, and then laying the new planks. Each stage affects how flat, solid and consistent the finished floor will be.

By Los Angeles Hardwoods · October 24, 2026

Step 1: evaluating the existing subfloor

Before any hardwood is ordered or installed, the surface underneath has to be checked. That means looking at the subfloor's condition, finding loose or damaged areas, deciding what existing flooring has to come out, checking the plywood itself, and considering moisture. All of it is measured against the installation requirements of the specific flooring product.

An important distinction: flat is not the same as level. Level means horizontal, like a reading on a spirit level. Flat means the surface doesn't rise and dip over short distances. Hardwood manufacturers specify flatness tolerances, commonly around 3/16 inch within 10 feet or 1/8 inch within 6 feet, and some products are stricter. A floor doesn't need to be perfectly level to receive hardwood, but it does need to meet the flatness requirement of the product being installed.

Step 2: preparing the plywood subfloor

Several rooms in this home were down to plywood. A hardwood floor is only as stable as what it sits on, so plywood is typically checked for loose or moving panels, fasteners that stand proud of the surface, damaged sections and surface irregularities, and then cleaned of debris. In the kitchen photo, the subfloor has been swept clean, with a plank of the new flooring laid out on it.

Exactly what a plywood subfloor needs depends on the flooring product and the installation method the manufacturer approves. That is why we evaluate it at the estimate rather than assume. More on floor removal and subfloor preparation.

Step 3: correcting uneven areas with floor-leveling compound

Uneven subfloors cause problems for hardwood: planks can rock or flex over low spots, seams can open, and boards may not sit tight to each other. On this project, low areas were filled with self-leveling compound while higher plywood was left exposed, which you can see where the gray compound gives way to bare wood. Plywood seams were taped where the compound meets them.

Leveling compounds are not a universal fix. The product has to be chosen and applied according to its manufacturer's requirements. Not every self-leveling underlayment is suitable directly over plywood; some systems require a specific primer, reinforcement such as lath, a minimum thickness, or other preparation, and every one has drying or curing times before flooring can go over it. The leveler also has to be compatible with the hardwood flooring system and its installation method. Done properly, addressing high and low spots before installation helps the new floor go down flat and reduces installation-related problems.

Step 4: preparing the hardwood materials

Before installation, the flooring was staged in the home. Typical steps at this point include checking the material's condition, confirming the product specifications, evaluating the jobsite's conditions, testing moisture where the manufacturer requires it, following the manufacturer's acclimation instructions, and planning the layout and transitions. Acclimation requirements differ from product to product, so we follow the instructions for the specific floor rather than a single rule.

Step 5: installing the hardwood flooring

With the subfloor ready, the dark-toned wide planks went down. Good installation comes down to details: a layout planned so boards run with the room's main sightlines, end joints staggered so seams don't line up, appropriate expansion space at walls and doorways, transitions checked as the floor reaches other rooms, and the manufacturer's installation instructions followed throughout.

Why do installers put blue tape on hardwood floors?

The blue tape in these photos is temporary. On some installations, installers apply tape across newly laid planks to help keep them aligned and their seams closed while the installation progresses. It is part of the process, not the final appearance of the floor.

• Not every hardwood installation needs tape.
• The tape must be compatible with the flooring's finish.
• It is applied and removed according to the manufacturer's recommendations.
• It helps during installation; it does not replace a proper installation method.

The finished floor

With the tape off, the result is a dark, wide-plank floor with a textured surface, light-highlighted grain and natural character marks running the length of the room. The photos were taken while other work in the house was still underway, so the walls, baseboards and fireplace aren't finished yet, but the floor itself is down. Trim moldings in the same finish were staged on cardboard, ready for the transitions.

Preparing staircases for hardwood flooring

This home's staircase was stripped back to its existing treads and risers during the project, with the new hardwood floor meeting the bottom step. Preparing a staircase for hardwood usually means evaluating the existing treads, risers and nosing, the step dimensions and the structure underneath before choosing how the stairs will be finished.

Los Angeles Hardwoods offers hardwood staircase installation, matching or coordinating stair noses (our flooring collections offer stair-nose solutions, subject to product availability), custom hardwood stair treads, and the transitions between floors and stairs. Those are our general services; the photos here show the staircase during preparation, not its finished state. See our hardwood stair installation service.

Why proper preparation matters for long-term performance

Careful preparation gives hardwood proper support, helps planks stay aligned, reduces the risk of movement-related issues, keeps the installation consistent from room to room and keeps the job within the manufacturer's requirements. It doesn't guarantee a floor will never have a problem, but skipping it is one of the most common reasons hardwood floors fail early.

Project specifications

Location

Pasadena, California

Project type

Residential hardwood flooring installation

Subfloor

Plywood

Preparation

Subfloor preparation; self-leveling compound where necessary

Flooring

Dark-toned wide-plank hardwood

Installation detail

Temporary blue tape to help maintain seam alignment

Stairs

Existing staircase prepared during the project

Professional hardwood flooring installation in Pasadena, CA

Los Angeles Hardwoods serves homeowners in Pasadena and surrounding Los Angeles communities who want hardwood flooring installed properly, from the subfloor up. We work with engineered hardwood, European white oak and wide-plank floors, along with subfloor preparation, floor leveling and staircase installation. Learn more about our hardwood flooring installation in Pasadena; we also bring samples to nearby foothill homes in Bradbury and San Marino. See our hardwood flooring installation service and how the in-home estimate works. See more projects in our work.