What Is Kempas Wood?

Kempas is a dense tropical hardwood from Southeast Asia, identified botanically as Koompassia malaccensis. It is used for flooring and has a commonly reported Janka hardness of about 1,710 lbf. For a lasting floor, the wood’s density matters, but so do moisture control, a suitable subfloor, and installation that follows the flooring maker’s instructions.

The confusing part is that a tough wood can still fail if the floor beneath it is damp, uneven, or poorly supported. I focus on the full floor assembly, not a single hardness number. Below, I explain what kempas is, what its specifications tell you, and what to check before you install it.

What is kempas wood?

Kempas is the common name for Koompassia malaccensis, a tropical hardwood native to Southeast Asia. It is sold as solid or engineered flooring, depending on the product. Its hardness can help describe resistance to denting, but it cannot tell you whether a particular floor suits your room or installation method.

Kempas is often described as reddish or orange-brown. Color and grain can vary among boards, so look at samples from the actual product line before choosing a finish or planning a room. A sample can also help you judge how the wood looks under your lighting.

The species name is useful when checking product information. “Kempas” identifies the wood, but it does not specify whether flooring is solid or engineered, how thick its wear surface is, or which installation methods are approved. Those details belong to the product’s technical sheet and installation guide.

What do kempas wood’s hardness and other specs mean?

A specification is useful only when you know what it measures. Kempas is commonly listed at about 1,710 pounds-force (lbf) on the Janka hardness test. That result gives a way to compare resistance to indentation, but it does not predict every kind of wear or replace product-specific installation requirements.

The Janka test measures the force needed to press a steel ball partway into a wood sample. It is a comparison tool, not a promise that a floor will never dent, scratch, or wear. Furniture, grit, dropped objects, finish type, and upkeep all affect the floor’s appearance over time.

Do not treat “dense” or “hard” as a complete durability rating. For a practical choice, compare the construction, finish, care instructions, warranty terms, and permitted installation methods for the exact product. Kempas’s Janka figure is a species-level reference, and actual stock can vary.

Kempas flooring: substrate inspection, moisture testing, and subfloor preparation

The substrate is the surface that supports the flooring, such as a plywood subfloor or concrete slab. Before installation, confirm that it is sound, clean, flat, and within the product’s moisture limits. A sound-looking surface is not proof that it is dry enough for kempas or its adhesive.

Check wood subfloors

Inspect the subfloor for loose panels, movement, damage, and debris. Repair weak or moving areas before covering them. Measure moisture in both the flooring and wood subfloor with a calibrated meter, following the meter and flooring makers’ instructions.

Compare readings using the flooring manufacturer’s permitted difference. A commonly cited NWFA guideline is no more than 2 percentage points between solid strip flooring under 3 inches wide and its wood subfloor; wider boards may require a tighter limit. Confirm the current guidance and the specific product requirements before work begins.

Check flatness with a straightedge or other suitable method. For typical wood-floor installations, 3/16 inch over 10 feet is a commonly used benchmark, but it is not a universal allowance. The flooring maker’s stated limit controls. Correct high and low spots using a method approved for the subfloor and flooring.

Check concrete slabs

Concrete moisture needs a test method and acceptance limit suited to the complete flooring and adhesive system. ASTM F2170 measures relative humidity inside a concrete slab. ASTM F1869 measures moisture vapor emission rate at the slab surface. Use the method required by the product instructions.

There is no single safe relative-humidity or emission-rate limit for every kempas floor. Compare test results with the published limits for the flooring and adhesive you plan to use. If readings are too high, do not assume a generic membrane or adhesive will solve the problem. Find and correct the moisture source, then use only a specified mitigation system.

Kempas installation: acclimation, fastening, and precision layout

Installation method depends on whether the kempas is solid or engineered and on the product’s approved instructions. Acclimate only as directed by its manufacturer; there is no reliable one-size-fits-all number of days. Record room conditions and moisture readings, and plan the board layout before fastening or bonding.

Keep the flooring in the installation environment as the manufacturer directs. Acclimation does not fix a wet slab or an unready subfloor. It is one part of preparation, alongside moisture checks and stable site conditions.

Before laying boards, plan the starting line, board direction, staggered end joints, and cuts at walls and doorways. Follow the product’s instructions for end-joint spacing and board layout. Do not force boards tightly together if the specified method calls for normal fitting; dense wood should not be driven into compression.

Use only the fastening or bonding method approved for that product and substrate. For nailed solid kempas, its density can make splitting a concern. Use the recommended fastener and tool settings, and predrill where the manufacturer requires it. For concrete, use the approved adhesive or vapor-control system; do not substitute a product based on a general claim of compatibility.

Before starting, verify:

• The product is approved for the substrate and chosen installation method.
• Subfloor flatness and moisture meet the written limits.
• The required tools, fasteners, adhesive, and accessories are on hand.
• The planned layout allows for the specified gaps and transition details.

Transitions, perimeter clearances, safety, and deflection compliance

Perimeter clearance is the space left between flooring and fixed edges so the floor can move as conditions change. Follow the product’s required clearance at walls, pipes, cabinets, and other fixed objects. Trim can cover the gap, but it should not pin the floor unless the installation instructions say otherwise.

Use appropriate transition profiles at doorways and where the floor meets another surface, as required by the product instructions. Transitions protect exposed edges and allow the floor assembly to meet adjoining surfaces. Do not cover a required movement gap with a detail that blocks movement.

For wood framing, verify that the complete floor assembly meets the required deflection performance. L/360 means that under the specified load, the structure’s calculated deflection is limited to the span divided by 360. Check the framing, joists, subfloor, and flooring maker’s requirements; do not treat the flooring board alone as proof of compliance.

Kempas is flooring, not a tile underlayment or an uncoupling-membrane application. If your project involves tile, use a tile assembly designed for that purpose. Keep flooring and tile systems distinct, and follow each system’s instructions.

Kempas maintenance, finish care, and moisture protection

Maintenance depends on the product’s finish and care instructions. Keep grit off the surface, use cleaning products approved for the finish, and avoid leaving spills or standing water on the floor. A hard wood can still be scratched, stained, or affected by excess moisture.

For unfinished kempas, use a finish system suitable for the wood and follow its preparation and application directions. For factory-finished flooring, do not assume that a site-applied coating is suitable; check with the manufacturer. Protect the floor during nearby work from water, impact, and abrasive debris.

Watch for signs such as cupping, gaps, or boards that appear to lift. These may have several causes, including moisture or installation problems, so appearance alone does not identify the source. Check the floor and subfloor conditions and seek professional assessment if movement continues.

Kempas flooring scenarios: what the checks change

These examples are illustrative, not reports of specific jobs. They show how the same wood can require different decisions based on its substrate, moisture readings, and product instructions. The practical lesson is to confirm the complete installation system before buying materials or beginning work.

• Wood-framed room: A homeowner plans solid kempas over plywood. The wood is dense, so the installer checks the product’s nailing instructions and predrills where required. They also measure moisture in the flooring and subfloor, check flatness, and confirm the floor assembly meets the applicable deflection requirements.
• Concrete slab: A builder plans engineered kempas over concrete. They first confirm that the product allows this substrate and method. They test the slab using the method required by the adhesive system and compare results with its published limit. If the slab fails, they address the moisture issue before installing.
• Uneven subfloor: A DIY installer finds a high spot and a low area. Rather than forcing boards flat with fasteners, they check the product’s flatness limit and correct the substrate with an approved method. This reduces the risk of an uneven, poorly supported floor.

How to decide whether kempas is right for your project

Kempas is a Southeast Asian hardwood with a commonly reported Janka hardness near 1,710 lbf. That makes it a firm flooring option, but the species name and hardness figure are only a starting point. Check the product construction, approved installation method, moisture limits, and care instructions.

Before you proceed, match the flooring to the substrate, test moisture using the required method, prepare the surface to the maker’s flatness limit, and plan fastening, clearance, and transitions. If any requirement is unclear, pause and get written guidance from the flooring or adhesive manufacturer.

Kempas wood FAQs

These brief answers define common terms and address the most frequent product and installation questions. Product requirements can differ, so use the instructions for the specific kempas flooring, adhesive, and subfloor system rather than relying on a general rule.

What is kempas wood?
Kempas is a tropical hardwood native to Southeast Asia. Its botanical name is Koompassia malaccensis, and it is used in flooring products.

Is kempas a hardwood?
Yes. Kempas is a hardwood, and its commonly reported Janka hardness is about 1,710 lbf. Hardness does not mean it is scratch-proof or immune to moisture damage.

Is kempas suitable for flooring?
Kempas is used for flooring, but suitability depends on the particular product, room, substrate, and installation method. Follow its technical sheet and installation guide.

What does a Janka rating of 1,710 lbf mean?
It is a commonly reported measure of the force needed to press a steel ball into a wood sample. It compares indentation resistance, not every type of floor wear.

Can kempas flooring go over concrete?
Only if that flooring product permits concrete and you use its approved adhesive or vapor-control system. Test slab moisture by the method required for that system.

Does kempas need to acclimate before installation?
Follow the product maker’s acclimation directions. Do not use acclimation as a substitute for moisture testing or correcting a wet or unsuitable subfloor.

Should kempas be predrilled before nailing?
Use the manufacturer’s fastening instructions. Because kempas is dense, predrilling may be required to reduce splitting with the specified fasteners.

What moisture limit should concrete meet?
There is no universal safe limit for all kempas flooring systems. The flooring and adhesive makers’ published limits and required test method control.

Can kempas be used under tile as an uncoupling layer?
No. Kempas flooring is not a tile underlayment or uncoupling membrane. Use a tile assembly made for that purpose.

What does L/360 mean for a kempas floor?
It is a deflection limit used to describe how much a floor structure can bend under a specified load. Check the complete wood-framed assembly and the flooring maker’s requirements.

(This article was written by one of our staff writers, Marcus Vance. Visit our Meet the Team page.)