Subfloor Checklist Before Engineered Hardwood Installation

Before engineered hardwood is installed, the subfloor should be identified, structurally sound, clean, dry, and flat enough for the selected product and installation method. Those words sound simple, but they must be supported by measurements and site observations. A visual glance alone cannot confirm moisture, flatness, or the condition hidden beneath an existing floor.

Homeowners do not need to perform the installer’s technical work. It is still useful to ask what was checked and, when available, keep a brief record of moisture, room conditions, and flatness observations. This checklist helps organize that conversation before cartons are opened and boards are installed.

1. Identify the subfloor and everything above it

Start by confirming what is directly below the new floor. Common conditions include a concrete slab, plywood or oriented-strand-board panels over joists, or an existing approved surface that the installer has evaluated.

Do not assume the same condition continues throughout the home. Additions, stairs, and transitions may have different assemblies or hidden patches.

Ask the installer to record:

• Subfloor type in each installation area

• Existing materials that will be removed or retained

• Crawl space, basement, or slab conditions below

• Known repairs, patches, cracks, or water events

• Changes in height between rooms

• The approved installation method for the selected flooring

If the existing floor has to be removed before anyone can see what is underneath, expect the first estimate to change. Ask the installer to update it after the subfloor is exposed.

2. Look for movement, damage, and unfinished repairs

Walk the wood subfloor with the installer. Note any flexing, loose seams, squeaks, broken panel edges, or soft areas, then determine what is causing them before the new floor goes down. New planks should not be used to hide a weak base.

For a concrete slab, photograph and review visible cracks, patches, old coatings, stains, and residue. If a condition falls outside the installer’s scope, bring in the appropriate specialist before work continues.

Confirm in writing who will handle each correction. A flooring proposal does not always include framing work, slab repair, or leak investigation.

Bentham Plank’s warranty states that the subfloor must be clean, dry, flat, and structurally sound according to the installation instructions. It also excludes certain damage related to improper installation and subfloor moisture. Resolve responsibilities in writing before installation begins.

3. Measure moisture—do not rely on appearance

A surface can look dry while containing too much moisture for the planned system. The installer should use the appropriate test method for the subfloor and document the results. Wood subfloors and concrete slabs are evaluated differently, and adhesive manufacturers may have their own requirements.

Ask these questions:

• What test method and meter were used?

• Where and how many readings were taken?

• What were the results?

• Which manufacturer limit is being applied?

• Were indoor temperature and relative humidity recorded?

• Does the slab require a moisture-control system or a different installation plan?

Do not ask for one universal “safe” reading. The material, test method, product, adhesive, and instructions determine how a number is interpreted.

If there has been a plumbing leak, flood, wet construction work, or an unexplained odor, stop and investigate the source. Flooring should not be used to conceal an active moisture problem.

4. Check flatness across the installation area

Flatness is not the same as level. A floor can slope gradually and still be flat, while a level-looking room may contain short dips and humps that interfere with installation.

The installer should check the surface with an appropriate straightedge or other method and compare the results with the product and adhesive instructions. High spots may need to be reduced; low areas may need an approved patch or leveling material. The repair product must be compatible with the subfloor and the planned adhesive or underlayment.

Ask the installer to mark problem areas and confirm the surface again after correction. Uneven support can contribute to movement or an unsatisfactory result.

5. Remove dust, debris, coatings, and incompatible residues

The final surface must be clean enough for the approved installation method. Dust, paint, drywall compound, wax, oil, curing compounds, old adhesive, or loose patching material can interfere with bonding and create unevenness.

If old flooring or adhesive may contain regulated materials, do not sand, grind, or scrape it casually. Arrange appropriate testing and qualified removal before the flooring project proceeds.

6. Plan finished height and transitions

The subfloor decision affects more than the boards. Add the flooring thickness, adhesive or underlayment, and any approved patch or leveling layer to estimate the finished height.

Check the result at:

• Exterior and interior doors

• Appliances and cabinetry

• Stair nosings and landings

• Floor vents

• Tile, carpet, and existing wood transitions

• Baseboards and door casings

• Accessible thresholds

Confirm matching moldings and stair components early because lead times may differ.

7. Confirm the installation method and product restrictions

Approved installation options depend on the exact product and site. Ask the dealer and installer to identify the current instructions, then confirm that the subfloor, adhesive, underlayment, fasteners, and environment comply.

If the project includes radiant heat, below-grade space, a condominium acoustic assembly, or a concrete slab, request written confirmation of the applicable product limitations. A product that works in one engineered-flooring project may not be approved in another.

8. Inspect the flooring before installation

Subfloor preparation and material inspection should happen before installation. Bentham’s shipping and return guidance asks for inspection of visible condition, color, and grade.

Confirm the collection, product, grade, finish, dimensions, carton count, and visible condition. Compare several boards in the room’s lighting and blend boards from multiple cartons as directed. If the delivery appears incorrect or damaged, contact the dealer before proceeding.

9. Keep a pre-installation record

Before the first board is installed, retain:

• Product and lot labels

• Current installation instructions

• Subfloor identification

• Moisture readings and test method

• Temperature and relative-humidity readings

• Flatness observations and corrections

• Photos of the prepared surface

• Products used for patching, moisture control, adhesive, or underlayment

• Written approval for any building or HOA requirement

Final homeowner questions

1. What is the subfloor in every room?

2. Is it structurally sound, clean, dry, and flat within the applicable limits?

3. What moisture and environmental measurements were recorded?

4. What corrections are required, and who is responsible?

5. Which installation method is approved for this exact product?

6. How will finished height and transitions be handled?

7. Are all materials and accessories on site and verified?

8. What documentation will I receive after installation?

Installation starts below the visible surface. For current information, contact Bentham Plank with the product, location, subfloor, and installation method.