Case Studies › Shutters
Shutters: Coastal Climate, Heat and Security
Field experience from the Garden Route on PVC, timber and aluminium shutters in real homes. How they cope with salt, heat, noise and day-to-day use.
Updated Policy Snapshot 2025/26
Quick Summary
- Where: Coastal and high-exposure zones from Plettenberg Bay through Knysna to Mossel Bay.
- Products: Indoor PVC shutters, timber shutters and aluminium security shutters.
- Main risks: Salt corrosion, brittle plastics in extreme heat, timber movement and aluminium cold transfer.
- Policy: Choose PVC or timber indoors for comfort and longevity. Reserve aluminium for specific external security use with marine-grade components and a clear maintenance plan.
1. Indoor PVC Shutters in Coastal Homes
PVC shutters are often the first choice for coastal interiors. They are moisture-ready, do not swell like timber and do not carry the same risk of mould growth on the substrate. In day-to-day Garden Route use they handle steam, splashes and high humidity well when the product is correctly specified.
The Hidden Problem Is Salt
Even with indoor shutters, fine salt crystals move through open windows and doors. Over time this salt settles in hinges, tilt mechanisms and tracks. The result is stiffer movement, squeaks and premature wear of moving parts in coastal homes compared with inland homes.
This is why two identical PVC shutter installs can age very differently. The product is not the only factor. The location and maintenance routine are just as important.
Coastal Maintenance Protocol
- Light dusting or vacuum on a soft brush setting as part of normal cleaning.
- Regular wipe-down of stiles and rails with mild soapy water then fresh water, especially on sea-facing openings.
- Check and tighten visible screws and hardware where needed. Replace low-grade steel fixings with stainless where corrosion appears.
2. PVC Shutters in Hot, Dry Inland or Fringe Areas
In very hot, dry conditions, lower-grade PVC products can become brittle or show surface movement. The problem is not the material category but how the product was formulated and manufactured.
On homes that experience long periods of high heat and strong sun, CB specifies cellular PVC with UV stabilisers and a proven performance record. These shutters stay more flexible, hold their colour and move less under temperature swing than cheaper alternatives.
Duncan’s Rule on PVC
Never treat PVC shutters as a generic product. Two white shutters can look identical on day one and behave very differently after three summers. We favour tested ranges with stable cores and documented UV performance rather than the cheapest option available. If a room combines strong sun, large windows and long periods of closure, we may guide you towards honeycomb blinds for better thermal comfort instead.
3. Timber Shutters and Climate Swing
Well-specified timber shutters are beautiful, warm and long-lasting, but they are still timber. They move with humidity and temperature. On the Garden Route we see both ends of the scale: coastal moisture on one side and dry heat pockets on the other.
Where Timber Shutters Perform
- Feature windows in lounges and bedrooms where look and feel come first.
- Homes that maintain reasonably stable indoor humidity and temperature.
- Clients who are comfortable following a light maintenance routine on finishes.
Installed correctly with the right coatings, timber shutters give a level of natural character that no other material matches.
When Timber Struggles
Extreme dry heat and large seasonal swings cause timber to shrink and move. This shows up as hairline cracks, joints opening and finishes lifting at edges. In these conditions CB is cautious with timber specification and may recommend PVC or fabric-based products instead.
For clients who specifically want timber we explain the trade-offs openly and document a care plan before the order is placed.
4. Aluminium Shutters for External Security
Aluminium shutters occupy a specific and important place in CB's range. They are not a comfort product for interiors. They are an external security and weather barrier, and in that role they perform well when correctly specified and maintained in coastal conditions.
Product Specifications
- Material: Architectural grade aluminium with powder-coat finish for corrosion resistance.
- Configurations: Hinged and bi-fold panel options. Available in even and odd panel numbers to suit the opening.
- Maximum panel width: 900mm per panel (both hinged and bi-fold configurations).
- Louvre operation: Louvres rotate and close in both directions for precise privacy and light control without a tilt rod.
- Locking: Key locks accessible from both sides of the panel as standard option. Uniform key option available for multiple shutters on one property.
- Colours: White, Light Grey, Charcoal and Bronze. All rust-resistant metal components.
- Warranty: Up to 7 years (terms and conditions apply).
- Applications: Suited for both internal and external use.
Why CB Specifies Aluminium Externally
Aluminium conducts heat and cold readily. In cold weather a room with aluminium shutters on the inside of the window feels noticeably colder around the glass than the same room with PVC or timber. On the Garden Route, where coastal homes already lose heat through large glazed areas, this is a real comfort issue.
CB's position is to deploy aluminium shutters where they do what no fabric blind can: provide a hard physical barrier against forced entry and storm debris on exposed elevations. Marine-grade fasteners and corrosion-resistant powder-coat finishes are specified as standard for every coastal installation. A written cleaning schedule is provided with every aluminium shutter quote.
For interior comfort needs, CB recommends PVC or timber shutters or honeycomb blinds.
CB’s Aluminium Shutter Policy in One View
- Aluminium shutters for external security and storm protection on exposed elevations only.
- Marine-grade powder-coat and rust-resistant hardware specified as standard for all coastal installs.
- Up to 7-year product warranty. CB documents a maintenance plan with every quote.
- Interior comfort needs addressed with PVC or timber shutters, not aluminium.
Where security and comfort both matter, CB often combines external aluminium shutters with interior PVC or timber shutters or honeycomb blinds for warmth and light control inside.
Frequently Asked Questions: Shutters on the Garden Route
What shutter material is best for a coastal home on the Garden Route?
PVC shutters are the first choice for most coastal interiors. They resist moisture, will not swell like timber, and do not harbour mould on the substrate. For external security on exposed elevations, aluminium shutters with a powder-coat finish and rust-resistant hardware are the correct specification. Timber shutters suit stable interior environments where maintenance is accepted and aesthetics come first.
How do aluminium security shutters differ from regular shutters?
Aluminium security shutters are built as a hard barrier rather than a light-control product. They use architectural grade aluminium panels in hinged or bi-fold configurations, key locks accessible from both sides, and rust-resistant metal components throughout. Louvres rotate in both directions for privacy and light control. The panel width is engineered for strength: maximum 900mm per panel in standard configurations. They are suited for both internal and external applications but CB recommends them primarily for external security use on the Garden Route coast.
Do CB's aluminium shutters come with a warranty?
Yes. CB's aluminium security shutters carry a warranty of up to 7 years, subject to terms and conditions. Every aluminium shutter installation on the Garden Route includes a written maintenance schedule covering cleaning frequency for coastal conditions, hardware checks, and care of the powder-coat finish. Following this schedule is the single most important factor in realising the full warranty period in a salt-air environment.
How do I maintain PVC shutters in a salty coastal environment?
Dust or vacuum on a soft brush setting regularly. Wipe stiles, rails and louvres with mild soapy water followed by a fresh water rinse, particularly on sea-facing openings. Check visible screws and hardware periodically and replace any standard steel fixings that show corrosion with stainless steel alternatives. In high-exposure coastal positions, CB recommends a wipe-down every one to four weeks rather than the three to six month inland schedule.
Can timber shutters cope with the Garden Route climate?
Yes, in the right rooms. Timber shutters perform well in stable indoor environments, feature rooms, and spaces where the client accepts a light maintenance routine on the finish. They struggle in extreme heat swings, very dry conditions, and high-humidity wet rooms where sustained moisture causes the timber to shrink, swell or develop hairline cracks over time. CB explains these trade-offs openly and documents a care plan before any timber shutter order is placed.
What colours are aluminium security shutters available in?
CB's aluminium security shutters are available in four powder-coated colours: White, Light Grey, Charcoal and Bronze. Custom colour matching is available for projects where the shutter finish needs to align precisely with the building's exterior palette. Duncan advises on finish selection during the site visit, taking into account sun exposure, salt proximity and the building's overall material language.
“Before you sign for any shutter system, work through your climate risks, comfort goals and security needs. One conversation upfront can prevent a very expensive replacement later.”
Duncan Kane
Founder, Custom Blinds. Shutter installations across the Garden Route since 2010.
Plan Your Shutters for Climate, Comfort and Security
Duncan assesses your specific climate exposure, comfort goals and security requirements before recommending any shutter product. Free site visit across the Garden Route.
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Custom Blinds® is a Garden Route window covering specialist established in 2010, serving Knysna, Plettenberg Bay, George, Sedgefield, Mossel Bay, and surrounding areas. We manufacture Custom Lifestyle Shutters in our Cape Town partner facility to marine-grade PVC specification for coastal conditions, and supply roller blinds, honeycomb blinds, venetian blinds, and no-drill blinds nationally via shop.customblinds.co.za. See our case studies hub for technical reports across all product categories.
