Solid Wood Flooring Installation: Nail-Down & Glue-Down Guide
A Practical Installation Guide for Nail-Down & Glue-Down Methods
Solid wood flooring is a premium, natural product that requires correct installation to perform as intended. Unlike floating floors, solid wood must be securely fixed to the subfloor to control natural movement and ensure long-term stability.
This guide provides clear, practical instruction for installing straight-lay solid wood plank flooring using approved nail-down and glue-down methods. It is written for confident DIYers and for homeowners who want to understand the correct installation process before appointing a professional fitter.
This guide covers:
- What solid wood flooring requires to perform properly
- Approved installation methods (nail-down and glue-down)
- Subfloor-specific guidance for timber and concrete bases
- Common installation mistakes to avoid
- A clear, step-by-step installation process
Important scope note:
This guide applies to solid wood planks only. Pattern installations such as herringbone, chevron, or panel layouts are not covered and should only be carried out by experienced professional installers.
Key Behaviour of Solid Wood
Solid wood flooring is manufactured from a single piece of natural timber. Unlike engineered or synthetic flooring, it remains hygroscopic, meaning it absorbs and releases moisture from the surrounding air throughout the year.
As indoor humidity rises and falls with seasonal changes, solid wood will naturally expand and contract across its width. This movement is normal and unavoidable — but it must be controlled through correct installation.
For this reason, solid wood flooring:
- Must be mechanically fixed (nail-down) or fully bonded (glue-down) to the subfloor
- Cannot be installed as a floating floor
- Requires defined expansion allowances around the perimeter and fixed objects
Floating installation does not provide sufficient restraint for solid wood. Without being fixed in place, seasonal movement can lead to gaps, cupping, distortion, creaking, or complete installation failure.
Understanding this behaviour is essential. The installation rules in this guide are not optional — they exist to manage the natural movement of solid timber and ensure the floor remains stable, functional, and visually consistent over time.
Installation Guide Contents
- 1. Tools & Materials Checklist
- 2. Pre-Installation Requirements
- 3. Subfloor Types & Preparation
- 4. Approved Installation Methods
- 5. Installation Planning & Layout
- 6. Solid Wood Flooring Installation – Step by Step
- 7. Expansion & Movement Allowances
- 8. Finishing & Aftercare
- 9. Common Installation Mistakes to Avoid
- 10. FAQs – Solid Wood Installation
- 11. Helpful Installation Videos & Visual Guides
1. Tools & Materials Checklist
Before starting installation, ensure all required tools and materials are available on site. Having everything prepared helps avoid interruptions once fixing begins.
Tools:
- Moisture meter (for timber and concrete subfloors)
- Flooring nailer or manual porta-nailer (for nail-down installation)
- Nail gun / Hammer and punch (for edge and final rows)
- Tape measure
- Spirit level or straight edge
- Saw (manual or electric)
- Rubber mallet
- Tapping block
- Pull bar
- Spacers
- Notched trowel (for glue-down installation)
Materials:
- Appropriate fixings or flexible wood flooring adhesive
- Damp-proof membrane (where required)
- Primer or levelling compound (if needed)
- Protective floor coverings for follow-on works
Personal Protective Equipment (PPE):
- Gloves
- Dust mask
- Knee pads
- Eye protection
Ensure all materials — particularly adhesives, primers, and fixings — are suitable for solid wood flooring and used in accordance with manufacturer instructions.
2. Pre-Installation Requirements
Before any solid wood flooring is installed, the site conditions, materials, and subfloor must meet specific requirements. These checks are essential. Skipping or shortening this stage is the most common cause of installation failure and will compromise the long-term performance of the floor.
Acclimatisation
Solid wood flooring must be allowed to acclimatise in the room where it will be installed.
- Acclimatise for 5–7 days under normal conditions
- Allow 7–10 days during winter months
- The room must be at normal living temperature and humidity
- Do not acclimatise in unheated, damp, or partially completed spaces
To allow the boards to adjust correctly:
- Remove any external plastic wrapping used for moisture protection
- Open the boxes along the taped seam to expose the board edges, rather than fully removing the boards (this allows airflow while keeping boards protected and is more time-efficient)
- Stack the boxes flat in the installation room (no more than 5–10 boxes high — the fewer, the better)
- Arrange stacks in rows with gaps between them to allow air circulation
- Do not stack directly against external walls
Acclimatisation allows the timber to stabilise to its new environment before being fixed in place. Installing boards straight from cold or storage conditions significantly increases the risk of excessive movement after installation.
Site Conditions
Solid wood flooring must only be installed once the building is dry, enclosed, and fully weather-tight.
Before installation:
- Heating systems must be operational and running normally
- Room temperature and humidity must be stable
- All wet trades (plastering, screeding, painting) must be fully completed and dried
- Excess moisture must not be present in the air or subfloor
Solid wood should never be installed in conditions that are still changing. Installing too early can trap moisture and lead to expansion, distortion, or joint failure once the building reaches normal living conditions.
Important: It is the installer’s responsibility to inspect the flooring prior to installation. Once the flooring has been installed, it is deemed to have been inspected and accepted.
Moisture Limits
Moisture control is critical when installing solid wood flooring. Excess moisture — whether in the subfloor or the surrounding environment — will cause the timber to expand and can lead to installation failure.
Maximum moisture limits:
- Timber subfloors: ≤12%
- Concrete or screeds: ≤3% moisture content (always follow adhesive and DPM manufacturer requirements)
- Where concrete exceeds this level, a suitable damp-proof membrane (DPM) must be applied
Moisture levels must be measured using appropriate testing equipment before installation begins.
Responsibility note:
It is the installer’s responsibility to confirm that moisture levels are within acceptable limits and that the subfloor is suitable for installation. Flooring should not be installed until these conditions are met.
Failure to control moisture at this stage can result in cupping, gapping, adhesive failure, or long-term structural issues with the floor.
3. Subfloor Types & Preparation
A solid, stable subfloor is essential for the successful installation of solid wood flooring. The subfloor must be structurally sound, dry, flat, and clean before any installation begins. Deficiencies at this stage will transfer directly into the finished floor and cannot be corrected once the boards are fixed.
Timber Subfloors
Solid wood flooring can be installed over suitable timber-based subfloors, provided they are stable and securely fixed.
Acceptable timber subfloors include:
- Existing floorboards in good structural condition
- Structural-grade plywood used as either:
- a structural deck installed over joists, or
- an overlay fixed over existing timber floors where required
Solid wood flooring must not be installed directly over open joists. Where joists are present, a suitable structural deck must first be installed.
Structural deck requirements (over joists):
- Minimum 18 mm structural-grade plywood (thicker may be required depending on joist spacing)
- Fixed securely to the joists using appropriate screws
- Fixings spaced closely enough to eliminate movement or flex
Overlay plywood (over existing floorboards, where required):
- Typically minimum 9 mm plywood
- Used to improve surface uniformity and rigidity, not to provide primary structural support
Before installation:
- Inspect existing floorboards for movement, flex, or damage
- Screw down any loose or creaking boards
- Replace damaged or excessively uneven sections
- Ensure the surface is flat and free from contamination
Any movement in the timber subfloor will be transferred into the finished floor, potentially causing noise, joint stress, or long-term failure.
Concrete & Screeds
When installing solid wood flooring over concrete or screeded subfloors, surface preparation and moisture control are critical.
Flatness:
The subfloor must be flat and level. As a general guide, deviation should be no more than 3mm over a 3m straightedge.
High spots should be ground down, and low areas filled using a suitable levelling compound compatible with wood flooring adhesives.
Moisture protection:
Concrete and screeds must meet the required moisture limits. Where moisture levels exceed acceptable thresholds, a suitable damp-proof membrane (DPM) must be applied before installation.
Some liquid DPM systems also act as primers. Where this is the case, follow the manufacturer’s guidance carefully to ensure compatibility with the chosen adhesive.
Drying times:
Allow all primers, DPMs, and levelling compounds to dry fully before proceeding. Installing flooring over uncured products can trap moisture and compromise both the adhesive bond and the wood itself.
This section provides a practical summary of subfloor requirements. For full step-by-step guidance on moisture testing, levelling, primers and damp-proofing options, refer to our Subfloor Preparation Guide before you begin.
4. Approved Installation Methods
Solid wood flooring must be installed using an approved fixed installation method. Mixing methods within the same installation area is not permitted unless specifically designed and approved for that purpose.
Nail-Down Installation
(Primary Method for Timber Subfloors)
Suitable for:
- Existing timber floorboards
- Structural plywood bases fixed securely to joists
This method fixes the boards mechanically to the subfloor, controlling natural movement while allowing seasonal expansion and contraction.
Key principles:
- Boards are secret (blind) nailed through the tongue at an angle into the subfloor
- Nails are typically driven at approximately 45° through the tongue
- Nail length must be appropriate for the board thickness and subfloor build-up
- Fixings must be selected carefully to avoid penetrating services beneath the subfloor, such as pipes or electrical cables
- Fixings are typically spaced every 200–300mm along the length of the board, with nails kept at least 50mm from board ends to reduce the risk of splitting the tongue. Always follow the flooring and fixing manufacturer’s guidance where specified.
- Boards should generally be laid perpendicular to the joists to maximise structural stability
- The first and last rows are usually face-fixed or hand-nailed where access for a flooring nailer is restricted
Correct nail spacing, alignment, and fixing depth are essential. Poor fixing can result in movement, noise, or long-term joint failure.
Glue-Down Installation
(Primary Method for Concrete & Screeds)
Suitable for:
- Concrete subfloors
- Sand/cement or anhydrite screeds
- Structural plywood subfloors
- Certain timber substrates where a full bond is specified
Glue-down installation fully bonds the solid wood flooring to the subfloor, providing restraint and stability across the entire surface.
Key principles:
- Use flexible polymer-based adhesives specifically designed for solid wood flooring
- Rigid or non-flexible adhesives must not be used
- Adhesive must be applied using the correct notched trowel, as specified by the adhesive manufacturer
- Work in controlled sections to ensure boards are laid within the adhesive’s open time
- Boards must be pressed firmly into place to achieve full adhesive contact
- Allow adequate curing time before foot traffic or loading
Glue-down installation requires careful timing and clean working practices. Once the adhesive begins to cure, repositioning boards becomes difficult and may compromise the bond.
Note on method selection:
The correct installation method is determined by the subfloor type, not personal preference. Where the subfloor changes, the installation method must also be reassessed.
Important Rule: Solid Wood Flooring Must Not Be Floated
Solid wood flooring must never be installed as a floating floor.
Solid wood is a hygroscopic, dimensionally active material. It absorbs and releases moisture from the surrounding air, causing natural expansion and contraction across the width of the boards as humidity levels change throughout the year.
Floating installation provides no restraint against this movement. Without being mechanically fixed or fully bonded to the subfloor, solid wood boards are free to shift, which can lead to:
- Excessive gapping between boards
- Cupping or distortion
- Joint stress and edge damage
- Creaking or floor movement
- Complete installation failure in severe cases
For this reason, solid wood flooring must always be installed using one of the following approved methods only:
- Nail-down installation over suitable timber subfloors
- Fully bonded glue-down installation using a flexible wood flooring adhesive
There are no approved floating systems for solid wood flooring.
5. Installation Planning & Layout
Careful planning before installation begins is essential. Once solid wood flooring is fixed in place, adjustments are difficult and mistakes are costly. All layout decisions should be confirmed before applying adhesive or driving fixings.
Board Direction
Solid wood planks are typically installed parallel to the longest wall in the room to create a balanced and visually consistent finish. Where the subfloor is timber with joists beneath, boards should generally be laid perpendicular to the joists to maximise structural stability.
Where boards must be laid parallel to the joists, the subfloor must first be overlaid with a suitable structural base (such as plywood) fixed securely across the joists to provide adequate support.
Natural Light
Where possible, consider installing boards so that the length of the planks runs in the same direction as the main source of natural light. This helps minimise the visibility of joints and creates a cleaner overall appearance, particularly with wider boards or natural grades.
Expansion Allowances (Reference)
Solid wood flooring requires perimeter expansion space to allow for natural movement. At the planning stage:
- Confirm that expansion gaps can be maintained around all walls and fixed objects
- Identify doorways, columns, and thresholds where allowance will be required
Full expansion rules are detailed later in this guide and must be followed exactly.
Dry-Lay Planning
Before fixing begins:
- Dry-lay several rows of boards to confirm the layout
- Check end joint positioning at both ends of the room
- Identify any areas where board widths or joint positions may need adjustment
This step is particularly important in narrow rooms or areas with multiple doorways.
Starter Boards & End-Joint Stagger
Plan the first row carefully to avoid narrow boards at the final row. If necessary, trim the first row so the last row remains a practical width.
Offcuts from the previous row can often be used as starter boards for the next row, helping maintain an effective stagger and reduce waste.
Maintain a minimum 300 mm stagger between end joints in adjacent rows (unless the product manufacturer states otherwise). Avoid creating H-joints (where end joints align across three consecutive rows) and avoid using very short offcuts at row ends.
Careful planning at this stage helps ensure a stronger, cleaner installation.
6. Solid Wood Flooring Installation – Step by Step
This section sets out the practical installation workflow for solid wood plank flooring. All planning, moisture checks, and preparation must be completed before starting. At this stage, the focus is on accurate execution.
7. Expansion & Movement Allowances
Solid wood flooring requires controlled expansion space to accommodate natural movement caused by seasonal changes in temperature and humidity. These allowances are not optional and must be maintained throughout the installation.
Failure to allow for movement will result in stress within the floor, leading to gapping, cupping, distortion, or structural failure.
Perimeter Expansion Gaps
- Allow a 10–15mm expansion gap around the entire perimeter of the room
- This gap must be maintained along all walls, including internal partition walls
- Use spacers during installation to ensure the gap remains consistent
The expansion gap allows the floor to move freely without pushing against fixed structures.
Fixed Objects
Expansion space must also be allowed around all fixed objects, including:
- Columns and structural posts
- Pipe penetrations
- Kitchen islands and fixed cabinetry
- Hearths and fireplace surrounds
Solid wood flooring must never be installed tightly against any fixed element.
Doorways & Thresholds
- Expansion allowance must be maintained at doorways and room transitions
- Where flooring continues through multiple rooms, suitable breaks or thresholds may be required
- Do not rely on skirting or architraves alone to restrain movement between areas
Doorways are common stress points and must be planned carefully.
Larger Areas
In larger or more complex spaces:
- Additional movement allowances may be required
- Long, uninterrupted runs increase the risk of cumulative expansion
- Expansion breaks or zoning may be necessary depending on room dimensions and layout
Where room sizes exceed typical domestic dimensions, manufacturer guidance should always be followed.
Seasonal & Environmental Allowance
Solid wood movement varies with seasonal humidity changes:
- Floors may expand during warmer, more humid periods
- Floors may contract during colder, drier periods
Expansion allowances must be sufficient to accommodate year-round conditions, not just the conditions at the time of installation.
Trim & Skirting Fixing Rules
- Skirting boards, trims, and beading must be fixed to walls or vertical surfaces only
- Never fix trims through the flooring itself
- Flooring must remain free to move beneath trims at all times
Fixing trims into the floor will restrict movement and can cause buckling or joint failure.
This section defines the only expansion and movement rules that apply to this installation. These allowances must be respected at all stages of planning, fixing, and finishing.
8. Finishing & Aftercare
Correct finishing and early aftercare are essential to protect newly installed solid wood flooring and ensure it performs as intended.
Foot Traffic
- Avoid walking on the floor until fixings are secure and any adhesive has fully cured
- Where adhesive has been used, allow a minimum of 24 hours before light foot traffic
- Avoid heavy traffic or point loads until the floor has fully stabilised
Always follow the adhesive manufacturer’s curing guidance where applicable.
Protection During Follow-On Works
If additional works are taking place after installation:
- Protect the floor using breathable protective coverings
- Avoid non-breathable plastic sheets, which can trap moisture
- Ensure protection remains clean and dry at all times
Protection should allow air circulation while shielding the floor from impact, dirt, and spills.
Furniture Placement
- Do not place heavy furniture on the floor until the installation has fully cured
- Lift furniture into position rather than dragging it across the surface
- Fit protective felt pads to chair and furniture legs before use
This helps prevent surface damage and unnecessary stress on newly installed boards.
First Clean & Ongoing Care
- Remove dust and debris using a soft brush or vacuum with a hard-floor setting
- Do not wet-clean the floor immediately after installation
- For oiled floors, follow the correct first-clean and maintenance procedures
For full guidance on cleaning and maintaining solid wood flooring — including naturally oiled finishes — refer to our wood flooring care and maintenance guide.
9. Common Installation Mistakes to Avoid
Many solid wood flooring issues arise not from the product itself, but from avoidable installation errors. Understanding these common mistakes helps prevent failure and ensures the floor performs as intended.
Installing Solid Wood as a Floating Floor
Solid wood flooring must not be installed as a floating system. Without being mechanically fixed or fully bonded, the boards cannot control natural movement, which can lead to gapping, cupping, distortion, or complete failure.
Ignoring Moisture Readings
Failing to test or act on moisture levels in the subfloor is a leading cause of flooring problems. Installing solid wood over excessive moisture can result in expansion, adhesive failure, or long-term structural issues.
Skipping Acclimatisation
Installing boards straight from delivery or cold storage does not allow the timber to stabilise to site conditions. This often leads to excessive movement after installation, including gapping or distortion.
Using the Incorrect Adhesive
Solid wood flooring requires flexible, polymer-based adhesives when fully bonded. Using rigid or unsuitable adhesives can cause bond failure and restrict natural movement within the floor.
Fixing Trims Through the Flooring
Skirting boards and trims must be fixed to walls or vertical surfaces only. Fixing trims through the flooring restricts movement and can cause buckling, cracking, or joint stress.
Installing Before the Site Is Ready
Installing solid wood before the building is dry, heated, and stable can trap moisture and lead to movement issues once conditions normalise. All wet trades must be fully completed before installation begins.
Avoiding these mistakes significantly reduces the risk of installation failure and helps ensure a stable, long-lasting solid wood floor.
10. FAQs – Solid Wood Installation
Solid wood flooring behaves differently to engineered or synthetic floors and requires stricter installation controls. These FAQs address the most common technical questions and misconceptions, helping clarify what is — and is not — acceptable when installing solid wood planks in UK homes.
In most domestic situations, solid wood flooring is not recommended for use with underfloor heating. Solid timber is highly sensitive to temperature and humidity changes, and UFH systems increase the risk of excessive movement, gapping, or distortion.
Where solid wood is considered, it must be carefully specified, fully bonded, and installed strictly in line with both flooring and UFH manufacturer guidance. Even then, performance risks remain. For UFH systems, engineered wood flooring is generally the more stable and suitable option.
No. Solid wood flooring must never be installed as a floating floor.
Solid wood is a hygroscopic, dimensionally active material. Without mechanical fixing or full bonding, the boards are free to move with seasonal humidity changes, which can result in gapping, cupping, creaking, or complete installation failure. There are no approved floating systems for solid wood flooring.
Yes — provided the concrete or screed meets strict preparation and moisture requirements.
The subfloor must be:
- Flat, sound, and clean
- Within acceptable moisture limits
- Protected with a suitable DPM where required
- A flexible polymer-based wood flooring adhesive must be used. Rigid adhesives are not suitable and can lead to bond failure or stress within the boards.
Yes. Solid wood flooring can be fully bonded to plywood provided the plywood is structural-grade, securely fixed, flat, and dry.
The plywood must be firmly fixed to the subfloor with appropriate fixings and spacing to eliminate movement. A flexible adhesive designed specifically for solid wood flooring must be used, and all moisture checks must be completed before installation begins.
Installing solid wood flooring over excessive moisture is one of the most common causes of failure.
- High moisture levels can lead to:
- Excessive expansion
- Cupping or distortion
- Adhesive breakdown
- Long-term structural issues
Flooring should never be installed until moisture levels are confirmed to be within acceptable limits or suitable moisture protection systems are in place.
Yes, but replacement is not straightforward, particularly with glue-down installations.
Replacing a board usually involves cutting out the damaged section and carefully bonding a new board into place. This process carries a risk of visible repair lines or surface damage. Boards should always be inspected and set aside before installation to minimise the need for post-installation repairs.
Solid wood flooring can be used in kitchens and busy domestic spaces only where site conditions are well controlled.
Spills must be cleaned promptly, humidity should remain stable, and expansion allowances must be correctly detailed. Solid wood is less forgiving than engineered wood or vinyl in environments with frequent moisture or temperature changes, so suitability should be considered carefully at the specification stage.
Light foot traffic is usually acceptable after fixings are secure or adhesive has cured. Heavy furniture should not be placed until the floor has fully stabilised. Furniture should always be lifted into position and fitted with protective pads to prevent surface damage.
11. Helpful Installation Videos & Visual Guides
This guide is written to provide clear, step-by-step instruction for installing solid wood flooring correctly. However, some installers and homeowners find it helpful to see certain techniques demonstrated visually alongside written guidance.
The videos referenced below are intended as visual support only. They should be used to reinforce understanding of key installation stages, not as a substitute for this guide or for manufacturer-specific instructions.
Always prioritise:
- The flooring manufacturer’s installation guidance
- Adhesive, fixing, primer, and DPM manufacturer instructions
- Site-specific conditions and professional judgement
Glue-Down Installation Over Concrete Subfloors
This video provides a complete visual overview of installing tongue-and-groove solid wood flooring using the fully bonded glue-down method over a concrete subfloor.
It supports the written guidance in this installation guide and demonstrates the full installation workflow, including:
- Moisture testing of the concrete subfloor
- Applying a suitable primer
- Checking subfloor flatness and preparation
- Allowing proper acclimatisation before installation
- Dry-lay planning and board layout assessment
- Factoring perimeter expansion gaps
- Applying flexible wood flooring adhesive correctly
- Fixing tongue-and-groove boards into the adhesive bed
- Using tension straps to secure boards
- Working around pipes and cutting neatly around door architraves
- Maintaining joint staggering and avoiding weak layout patterns
- Installing trims and threshold bars correctly without restricting floor movement
The video reinforces the importance of moisture control, subfloor preparation, and correct adhesive use when installing solid wood over concrete.
It should be used as a visual reference alongside this written guide and the specific instructions provided by the flooring, adhesive, primer, and DPM manufacturers.
Nail-Down Installation Over Timber Subfloors
This video provides a practical visual overview of solid wood flooring installed using the nail-down method over a timber subfloor.
It supports the written guidance in this installation guide by demonstrating key stages of the process, including:
- Assessing and preparing a timber subfloor
- Planning board layout before fixing begins
- Calculating square metre coverage and allowing for wastage
- Allowing proper acclimatisation before installation
- Establishing and maintaining correct perimeter expansion gaps
- Setting out and securing the first row
- Staggering end joints correctly and avoiding “H-joints”
- Secret (blind) nailing through the tongue using a flooring nailer
- Face-fixing where access is restricted (such as at starting and finishing walls)
- Transitioning between manual nailing and mechanical secret nailing
- Measuring and fitting the final rows accurately
This video is intended as a visual reinforcement of best practice. Always follow the flooring manufacturer’s fixing requirements and site-specific conditions when carrying out a nail-down installation.
Final Guidance
Solid wood flooring is a premium, natural product that rewards careful planning and correct installation. When site conditions are stable, moisture is properly controlled, and the correct fixed installation method is used, solid timber floors can provide decades of durability and character.
Most installation failures occur not because of the material itself, but because key preparation steps were overlooked or movement allowances were restricted. Following the guidance in this document — particularly around moisture control, fixing method selection, and expansion detailing — is essential to achieving a stable and long-lasting result.
If site conditions involve underfloor heating, large open-plan areas, or elevated moisture risk, consider whether engineered wood flooring may be the more suitable specification.
For ongoing performance, always follow appropriate care and maintenance procedures once installation is complete.
Explore Our Solid Wood Plank Flooring Range
This installation guide applies specifically to straight-lay solid wood plank flooring installed using approved nail-down or fully bonded methods.
If you are planning a solid timber floor, explore our collection of solid wood planks available in a range of widths, finishes, and natural grades — all suitable for fixed installation over properly prepared subfloors.
Each product listing includes key technical information to help you specify correctly, including thickness, fixing method suitability, and moisture guidance.
Browse the range below to find the right solid wood plank flooring for your project.
White
Invisible
Natural
Golden
Brown
Grey
Black
