Plywood Installation Best Practices: A Builder's Guide

1st Nov 2023 -

Plywood serves as the backbone for countless construction projects, from subflooring to roofing and everything in between. For this feature, we will delve into the essential tips and methods that every builder should know to ensure the proper plywood installation.

If you are working on a residential renovation or a commercial development, our builder's guide will equip you with the knowledge to tackle plywood installation with confidence. 

What is plywood?

Plywood is an engineered wood product composed of multiple thin plies of wood veneers bonded together with adhesive. Its unique construction involves alternating the grain direction of adjacent layers, which enhances its strength, stability, and durability. Plywood comes in various grades and thicknesses and is suitable for a wide range of applications in construction and design.

One of the primary advantages of plywood is its exceptional strength-to-weight ratio. This makes it an ideal choice for projects requiring structural integrity without excessive weight. If it is used as a roof or wall sheathing, subflooring, or even as a base for decorative finishes, plywood provides consistent performance. 

Also, plywood is a cost-effective option compared to solid wood. This allows you to achieve high-quality results while staying within budget constraints. Its versatility, resistance to wear and tear and ease of customisation further contribute to plywood's popularity. Learn more about plywood uses and properties with our in-depth guide.

How to install plywood - 12 top tips

No matter the size of the job, getting plywood installation right is essential for structural integrity. Below, we set out 12 crucial top tips you need to know, from choosing the right plywood type to mastering the finishing touches. 

1. Choose the right plywood type

Start by selecting the appropriate plywood grade and thickness for your specific project. Whether it is exterior sheathing, subflooring, or decorative panelling, the right type is essential for optimal performance. Using the wrong type can lead to structural weaknesses and potential safety hazards.

2. Be careful with thin plywood

Pay meticulous attention when working with thin plywood sheets which can bend. It is a more flexible plywood type compared to thicker plywood and is more prone to warping or sagging. During installation, consider adding a backer board for extra support and avoid overloading. 

3. Prepare the surface

Ensure the installation surface is clean, level, and free of debris. Properly addressing any underlying issues, such as moisture or unevenness, is crucial to prevent future problems. Neglecting these issues can result in warping, rotting and compromised stability. 

4. Acclimatise the plywood

Be sure to acclimate plywood panels to interior conditions before you start the installation process. This will prevent expansion or contraction issues. You should allow the plywood to sit in the project room for 1-2 days.

5. Secure properly

Use the right screw or nail fasteners spaced at recommended intervals to secure the plywood. Overdriven or underdriven fasteners can compromise the structural integrity of the installation.

6. Mind the gaps

Leave a small gap between each plywood sheet to allow for natural expansion due to temperature and humidity changes. Failing to leave small gaps can lead to buckling and swelling. Be sure to refer to manufacturer guidelines for specific gap recommendations. 

7. Stagger the joints

To enhance stability and distribute loads evenly, stagger the joints between adjacent plywood sheets. As a result, this prevents weak spots in the installation. Not staggering joints correctly can decrease the overall structural integrity. 

8. Seal edges

Be sure to apply wood sealer or edge banding to seal any exposed edges of plywood. This helps protect against moisture infiltration, which can cause swelling. Also, your plywood installation could be at risk of rot and warping. 

9. Consider adhesive

In addition to fasteners, consider using construction adhesive to bond the plywood to the substrate, providing extra strength and minimising squeaks.

10. Test for flatness

Make sure you use a straight edge or level to ensure the installed plywood is flat and even. You should make any necessary adjustments before proceeding with subsequent layers or finishes.

11. Finish appropriately

Whether you are working on a door or subfloor, finish it using paint, stain solution, or a suitable sealant. This will help to enhance its appearance and protect the plywood texture from tough environmental factors. 

12. Prepare for tiling

Before using tiles on plywood, ensure a stable and moisture-resistant base by applying a high-quality primer and a waterproofing membrane. This crucial step helps prevent potential tile adhesion issues and ensures a long-lasting, attractive tile installation. 

Can you use nails instead of screws for plywood?

The choice between screws and nails depends on several factors. Screws are a popular choice due to their excellent holding power and versatility. They provide a strong and secure connection between the plywood and the substrate, which is crucial for structural integrity. Additionally, screws are less likely to work themselves loose over time. This makes them ideal for projects where durability is essential. 

For plywood installation, wood screws or deck screws are often recommended. These screws have a coarse thread that bites into the wood, providing a solid grip. It is essential to select screws of an appropriate length to ensure they penetrate the plywood and firmly anchor it to the substrate.

Nails are also still a viable option for plywood installation. They are quicker to install than screws. However, nails may not provide the same level of holding power as screws. This makes them better suited for non-structural applications where ease and speed of installation are a priority. 

Overall, screws are the preferred choice for plywood installation, especially when strength and longevity are critical. But nails can still be a suitable option for projects where speed and ease of installation outweigh the need for maximum holding power. 

What tools and materials will you need?

Whether you are tackling a flooring with plywood project or an exterior waterproof plywood job, a well-equipped toolkit can make all the difference. We highlight the essential tools and materials you need to ensure a flawless plywood installation. From precision cutting to secure fastening and removing old plywood sheets, we have got you covered.

Circular saw or table saw	Plywood sheets
Safety goggles	Dust mask
Spirit level	Drill
Screws or nails	Circular saw guide
Orbital sander	Clamps
Pry bar	Tape measure
Crowbar	Screwdriver bits
Sealant	Wood glue

How much plywood should you use?

Determining the right quantity of plywood is a crucial step in ensuring a smooth installation. Buying too much plywood can lead to unnecessary expenses while buying too little can cause delays. Here are the 4 steps to take into account and achieve the right balance.

1. Measure the area

Start by measuring the area where you plan to install plywood. For a simple rectangular or square space, multiply the length by the width to find the total square footage. If your project involves irregular shapes or multiple sections, break it down into smaller, manageable areas and measure each one separately.

2. Consider plywood thickness

Plywood comes in various thicknesses. Choose the appropriate thickness based on your project's requirements. Thicker plywood is sturdier but also heavier and more expensive. Using the wrong thickness of plywood may compromise your project's structural stability and safety, leading to potential failures or instability.

3. Account for excess

It is wise to purchase a bit more plywood than your exact measurements indicate. This accounts for any mistakes during cutting, unexpected damage, or future repairs. A common rule of thumb is to add 10% to 20% to your total square footage to ensure you have enough material.

4. Calculate the quantity

With your square footage and overages in mind, calculate the number of plywood sheets you will need. For example, if your project area measures 300 square feet, and you are using 2440mm x 1220mm sheets with a 10% overage, you should use this formula to work it out: Quantity = (300 x 1.10) / 32. In this case, you would need to buy 11 plywood sheets. 

Why do exterior projects require more plywood?

You will likely require more plywood for exterior plywood projects vs interior jobs due to a range of factors. Below, we explore these factors in detail to help you make the best choices. 

Exposure to harsh weather

Exterior plywood installations are exposed to the elements, including rain, snow, UV rays, and temperature fluctuations. To withstand these conditions, exterior-grade plywood such as anti-slip plywood is used, which is thicker and more robust.

The need for thicker plywood naturally results in a higher quantity. 

Enhanced durability

Overall, exterior projects often demand a higher level of structural integrity and longevity. To meet these requirements, thicker plywood such as marine plywood is used. The increased thickness and strength contribute to the need for more plywood sheets.

Seam sealing

Outdoor installations require meticulous seam sealing and waterproofing to prevent moisture penetration. This involves covering seams and edges with sealant or tape. It can increase the overall quantity of plywood needed to account for these sealing and overlapping requirements.

Complex shapes and angles

Exterior projects often feature more complex designs, shapes, and angles. Cutting plywood to fit these intricate patterns can result in greater waste, adding to the quantity needed.

Overages for future repairs

Given that exterior installations are exposed to more wear and tear, it is wise to purchase extra plywood. This surplus ensures that you have the same type and colour of plywood available for any necessary maintenance or repairs. 

Is plywood easy to repair and refinish?

One of the advantages of plywood sheets is that it is relatively easy to repair and refinish compared to solid wood. While no material is immune to damage, plywood offers some forgiving repair options. Minor surface damage like scratches or dents can often be sanded out of plywood.

The veneers are thick enough to allow for light resurfacing while maintaining structural integrity. For deeper damage, filler can be used to rebuild the plywood edge or surface before sanding and refinishing.

The layered construction of plywood also means that small holes or gaps are simple to patch. To fix this, cut a piece of plywood slightly larger than the hole, apply adhesive, and clamp until dry. The patch piece will be flush with the existing surface after sanding smooth.

Split or lifted veneer plywood can also be repaired using wood glue injected under the lifted area. Clamping and weight are applied while the adhesive cures. 

Refinishing plywood involves sanding to remove any existing coatings or flaws. Also, this can include cleaning the surface and applying a stain solution, painting plywood, or using a clear finish like polyurethane. Plywood which is factory-finished may require a chemical stripper to remove the old finish before refinishing.

While plywood cannot be continually resurfaced like solid wood, it generally accepts normal refinishing jobs well. The smooth faces invite refreshed stain solution or paint. With the right tools and patience, plywood can be kept looking like new for years before replacement is needed.