Shutter Slat Size Guide

Choosing the Right Louvre for Your Home

When choosing plantation shutters, slat size is about far more than appearance. It affects how much light enters the room, how privacy is managed, how the shutter panels are constructed, and how the shutters sit within the window recess.

Each slat size offers a different balance between light control, privacy, rail placement, and the overall visual feel of the room. Larger slats allow more light and outward visibility, but they require greater recess depth, which can cause the shutter frame to project further into the room — something that can make smaller spaces feel more enclosed.

Smaller slats sit closer to the glass, maintain a neater profile, and often align more naturally with window panes. This makes them particularly well suited to bay windows, shallower recesses, and rooms where preserving space and light is important.

• Slat size directly affects light control and privacy
• Larger slats require deeper recesses and larger frames
• Smaller slats sit closer to the window for a neater finish
• Rail size and mid-rail placement are influenced by slat choice
• Slat-to-glass alignment is especially important in bay windows

We’ll guide you through the advantages and limitations of each slat size to help you choose a configuration that suits your windows, your room layout, and how you use the space day to day.

At a Glance – Why Slat Size Matters

• Light Control: Larger slats allow more light and visibility, while smaller slats offer tighter closure
• Privacy: Narrower slats provide greater privacy when partially open
• Recess Fit: Larger slats require the shutter to sit further forward in the window recess
• Room Impact: Shutters that project further into the room can make smaller spaces feel tighter
• Rail Size: Slat size influences the size and symmetry of top, bottom and mid-rails
• Mid-Rail Alignment: Larger slats increase variation in mid-rail placement across panels
• Slat-to-Glass Alignment: Smaller slats align more closely with window panes, which is especially important in bay windows
• Window Handle Clearance: Larger slats require more space, while smaller slats suit protruding handles
• Style & Proportion: Slat size affects the overall balance of the shutter, from classic to contemporary styles

📏 Slat Sizes We Offer

Every room, window, and aesthetic requires the right balance between visibility, privacy, and function. Below are the slat sizes we offer, along with where they work best and why.

47mm Slats

• Traditional appearance with narrow slat spacing
• Allows more slats per panel, providing maximum privacy and fine light filtering
• Available in our Fermain and Sark hardwood shutter ranges
• Well suited to smaller windows and period-style properties
• Can appear visually busy on taller or full-height panels

63mm Slats

• Our most popular and versatile slat size
• Ideal for bay windows and shallower recesses due to a tighter frame position
• Offers a strong balance between light control and privacy
• Compatible with most shutter ranges and room styles
• Often preferred where window handle clearance and glazing alignment are important

76mm Slats

• Clean, contemporary appearance with wider light gaps
• Well suited to bedrooms, living rooms and full-height shutter panels
• Fits comfortably within most standard window recesses
• Slightly greater variation in rail placement and panel symmetry compared to smaller slats

89mm Slats

• Bold, open appearance designed to maximise light and outward visibility
• Best suited to taller windows and tracked shutter systems
• Requires a deeper window recess and careful layout planning
• Creates a strong visual impact in larger rooms and open-plan spaces

114mm Slats

• Statement slat designed for very tall or visually dramatic windows
• Fewer slats per panel, which can reduce light gaps and support room darkening
• Not available in MDF shutter ranges
• Only suitable where window height and recess depth allow, and visual impact is a priority

How Slat Size Affects Construction

Shutters are not built around the slat alone — they are engineered as complete panels. Slat size plays an important role in how each panel is constructed, including rail proportions, panel height, and overall symmetry.

Rails and Mid-Rails

• Each shutter panel must contain a complete number of slats, so rail sizes adjust slightly to achieve the correct overall height
• Larger slats mean fewer slats per panel, which can result in taller top, bottom or mid-rails
• Mid-rail positioning varies more with larger slats, with alignment potentially shifting by up to half a slat

Bay Window Alignment

• In bay windows, alignment with the existing glass panes is important for visual flow and external symmetry
• Mid-rails are planned to align with window breaks such as sash lines or opening sections wherever possible
• Smaller slat sizes, such as 63mm, help maintain closer alignment between shutters and the window glass

Recess Depth and Frame Positioning

• Larger slats require the shutter panel to sit further forward in the recess to avoid clashing with window handles
• Smaller slats allow a tighter fit closer to the glass, helping preserve sill space and a sense of openness
• Incorrect positioning can make the shutter frame appear deeper than expected and reduce usable space

Room Slat Size Recommendations

Bay Windows

• 63mm slats are generally recommended for better slat-to-glass alignment
• Keeps the shutter closer to the window and maintains sill space
• Larger slats are usually avoided due to handle clearance and glass pane alignment issues

Bedrooms

• 63mm or 76mm slats are typically recommended, depending on privacy requirements and recess depth
• 76mm slats allow more light when paired with a mid-rail or blackout solution
• For improved room darkening and insulation, pairing shutters with Shutter & Shade is often effective

Living Rooms

• 76mm or 89mm slats are commonly chosen for a wider, brighter appearance
• 89mm slats work particularly well in open-plan or south-facing living spaces
• Slat size should be balanced with ceiling height and furniture scale for the best visual impact

Kitchens

• 63mm slats are often preferred due to tighter recesses and handle clearance
• Works well with café style shutters for privacy while maintaining light
• Helps preserve practical use of the window sill in working areas

Bathrooms

• In bathrooms, material choice is more important than slat size
• 63mm or 76mm slats work well for balancing moisture control and privacy
• Pair with waterproof shutter options such as ABS-coated (Herm range) or UK-made (Wisley range)

Tracked Shutters & Bifold Doors

Tracked shutters, particularly those fitted across bifold doors or wide glazed openings, have slightly different requirements when it comes to slat size and overall panel construction.

Because these panels are typically taller, a mid-rail is always required for structural strength. Larger slat sizes often work well in this context, especially where maximising light or creating a more open appearance is a priority.

• 76mm or 89mm slats are commonly specified for tracked shutters
• Larger slats mean fewer slats per panel, creating a cleaner and more open look
• Reduced slat count can help make folding smoother on larger panels
• Slats must be fully closed before folding the panels to prevent damage

Planning Track Systems Correctly

• Track layout is planned to ensure adequate clearance and smooth folding
• Mid-rail placement is calculated based on overall door height and rail visibility
• Slat size is selected to balance appearance, operation and structural requirements

For taller shutters, larger slat sizes often look better proportionally. However, final recommendations are always based on the specific room, how the doors are used, and the available recess depth to ensure long-term performance and ease of operation.

Cleaning Considerations by Slat Size

While all of our shutters are designed to be low maintenance, slat size can influence how easy they are to clean — particularly in kitchens, bathrooms and high-use areas.

• Larger slats (76mm, 89mm, 114mm) mean fewer slats per panel, resulting in fewer gaps to dust and quicker cleaning
• Smaller slats (47mm, 63mm) offer tighter closure and increased privacy but require more attention due to a higher number of slats per panel
• Use a soft cloth, feather duster or vacuum with a brush attachment to clean between slats
• Waterproof shutter ranges (such as Herm and Wisley) can be cleaned with a damp cloth and mild detergent, then dried thoroughly
• Real wood and MDF shutters should be kept dry — only use a very lightly damp cloth when necessary and never spray cleaners directly onto the surface

• Focus on high-contact areas such as tilt rods and handles
• Open shutter panels to clean behind them, including inside the frame
• Use a vacuum crevice tool to remove dust between the frame and window

Engineered Stiles

Most of our shutters are built using engineered stiles, which are created by laminating multiple layers of timber together. This construction method significantly improves dimensional stability and helps reduce the risk of warping over time.

Engineered stiles allow shutters to maintain their shape and alignment, particularly on taller panels and full-height installations. This contributes to the overall strength, durability and long-term performance of the shutters, helping ensure a consistent fit and reliable operation for years to come.

Traditional Mortise and Tenon Joints

All of our plantation shutters are constructed using traditional mortise and tenon joints — a proven carpentry method known for its strength, stability and long-term durability.

In this construction method, the rail slots directly into the stile of the shutter frame, creating a solid and secure joint without relying on dowels, glue blocks or short-lived fixings. This approach offers clear structural benefits:

• Minimises movement and reduces the risk of warping over time
• Reinforces the overall strength of the shutter frame
• Delivers a more durable, high-quality finish

This traditional joinery plays an important role in maintaining alignment and performance, particularly on full-height shutters and larger panels where long-term stability is essential.

UK-Made Shutters – The Wisley Range

Our Wisley range of UK-manufactured shutters offers a combination of quality, speed and sustainability, without compromising on performance or finish.

• Manufactured in the UK, supporting local production and reliable supply
• Fast lead times, with delivery and installation in as little as five weeks
• Lower environmental impact compared to imported alternatives
• Waterproof construction suitable for bathrooms, kitchens and humid environments
• Wide colour choice, available in nine carefully selected finishes

UK-made shutters are an ideal option for customers who require quicker turnaround times, prefer a more sustainable choice, or simply want the reassurance of British manufacturing alongside long-term durability.

Free Temporary Blinds While You Wait

When you order plantation shutters from us, we provide complimentary temporary blinds to cover your windows during the manufacturing period. This ensures you’re never left without privacy or control over light while your shutters are being made.

• Provided free of charge with a shutter order
• Quick and easy to install
• Neutral in colour with a discreet appearance
• Helps maintain privacy and comfort during the lead time

This is part of our commitment to making the process as smooth and stress-free as possible from order through to installation.

Our Service Commitment

We combine quality craftsmanship with a dependable, professional service to ensure every customer receives a smooth experience from initial advice through to installation and aftercare.

• In-House Fitting Team: All shutters are installed by our own experienced fitters. We never subcontract, so you deal with the same trusted team throughout the process.
• Post-Installation Checks: Once your shutters are fitted, we complete a detailed checklist to ensure everything is aligned, operating correctly and finished to a high standard before we leave.
• Long-Term Guarantees: All of our plantation shutters are supplied with a full 10-year guarantee for long-term peace of mind.
• UK-Made Options with Faster Lead Times: Our UK-manufactured shutter ranges can be produced and installed in as little as five weeks, ideal where timing is important.
• Established Experience: We have been trading since 2009, bringing years of hands-on knowledge to every consultation and installation.
• Free Temporary Blinds: While your shutters are being made, we provide complimentary temporary blinds so you’re never without privacy or light control.

Whether you’re fitting a single window or updating your entire home, our focus is on delivering a considered, reliable service with attention to detail at every stage.

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📧 Email: sales@blindsandshutter.co.uk

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