Composite vs wood shutters, and what to ask about MDF

Updated October 22, 2026

The short answer: composite is a family of materials, not one. Some are hollow plastic, some are foam-filled, some are fibreboard (MDF) under a coating, and some mix real wood with composite parts. Composite usually costs less. Solid wood can be sanded, repaired and repainted. Neither belongs in shower spray unless it’s sold as waterproof. Ask what’s inside, and read what the warranty says about water.

What “composite” means

Bloomin’ Blinds describes composite shutters as made from “engineered wood, PVC, or polymer materials rather than solid hardwood”, and says most are “hollow or foam-filled”^[1]. Hunter Douglas describes its NewStyle hybrid shutters as combining “the look of genuine wood with the durability of composite materials”^[2]. Neither description tells you what’s at the core of a louver, and that’s the part that matters.

In practice, “composite” on a quote usually means one of four things:

• MDF under a coating. Wood fibre and resin pressed into board, then painted or wrapped.
• Foam-filled or hollow plastic. A PVC or polymer shell with foam or air inside.
• Hybrid. Real wood in some parts, composite in others. Ask which parts are which.
• A branded substitute. A maker’s own material with its own name. Ask what it’s made of.

MDF and water: what the panel industry says

The clearest statement comes from the people who make the board. The Composite Panel Association’s technical bulletin says particleboard and MDF tend to “swell and expand when exposed to high humidity or water”, and that thickness swelling is “not fully recovered upon re-drying to the initial equilibrium moisture content”^[8]. In plain terms: once fibreboard has swollen, drying it out doesn’t put it back.

That’s why the coating matters so much on an MDF shutter. Where it’s intact, the core stays dry. Where it isn’t, at a chipped edge, a screw hole or a hinge cut, water can reach the fibre. Ask how those spots are sealed.

Composite and water: the makers’ fine print

Composite is often sold as the moisture-proof option. The makers’ own wording is more careful:

• Norman says its Woodlore Plus composite can handle high-moisture rooms “When equipped with the optional waterproof finish”^[3]. The waterproof version is an add-on.
• Blinds Chalet’s warranty excludes “deterioration from sunlight or moisture”^[4]. That warranty covers its window coverings generally, but it shows how sellers treat moisture.

So composite isn’t a free pass for a shower window. If a window gets wet, look for a product sold as waterproof, with a warranty that says so.

Wood and water

Solid wood isn’t immune either, and we won’t pretend it is. It takes on and loses moisture with the seasons; in heated buildings, the National Research Council of Canada puts it at about “6% in winter to 12% in summer”^[6]. The US Forest Products Laboratory explains that how much moisture wood holds depends on the humidity and temperature of the air around it^[7]. As wood gains moisture it swells slightly across the grain, and as it dries it shrinks^[6]. Paint slows that, and a dry, ventilated room keeps it in check. That’s why we say no to shower windows and yes to nearly everything else.

Room by room

For wet rooms, our aluminum interior shutters are coming in 2027. Made for bathrooms, laundry rooms and other rooms where wood has a hard time with moisture. Aluminum doesn’t rust the way steel does. A thin oxide film forms on its surface and reseals itself if it’s scratched. Aluminum shutters

What solid wood costs with us

From the live price list, in American poplar with flat moulding, 3½ in louvers and white paint: a small 24 × 36 in window is $160 – $200 ($230 – $290 CAD in Canada); a 36 × 48 in window is $320 – $400 ($460 – $570 CAD); a bedroom with two 36 × 48 in windows is $640 – $800 ($920 – $1,140 CAD). All before tax and shipping. When you compare with a composite quote, compare the same sizes and the same moulding, and ask for the louver core in writing. Price ranges for every size

Questions to ask about MDF and composite shutters

1. What is the louver core? Fibreboard, foam, hollow plastic or wood.
2. How are the edges and screw holes sealed? A coating protects a fibre core only where it’s intact.
3. What does the warranty exclude? Look for moisture, sun and fading.
4. Can it be trimmed if the opening is out of square? Wood can be lightly sanded; most coated cores can’t.
5. Can I repaint it in ten years? Ask what primer and paint the maker approves, if any.
6. What does one panel weigh? Weight tells you about the core, and about how hard the hinges work.
7. Which parts are composite? On a hybrid, ask whether it’s the louvers, the stiles, the frame or all three.

How to tell MDF from solid wood

Painted, the two look alike. A few ways to tell, short of asking:

• Look at an unpainted spot. The back of a hinge cut or the end of a louver pin hole shows either wood grain or uniform brown fibre.
• Feel the weight. MDF is dense and heavy for its size; a hollow or foam-filled louver is light.
• Read the spec sheet. “Hardwood” or a named species means wood. “Composite”, “engineered” or a brand name means ask again.

The best test is still the simplest: ask the seller to write the louver and stile material on the quote. A seller confident in the material will.

Reading a composite warranty

The warranty is where a maker says what it really expects of its material, so read the exclusions before the headline. Four lines to look for:

• Moisture. Blinds Chalet’s excludes “deterioration from sunlight or moisture”^[4]. If the warranty excludes moisture, the product isn’t warranted for a wet room, whatever the brochure says.
• A separate waterproof version. If, like Norman’s Woodlore Plus^[3], waterproofing is an option, make sure your quote includes it for the rooms that need it.
• Sun and fading. Coatings and plastics can yellow or fade; see whether that’s covered.
• Who it covers and for how long. The original buyer only, or the next owner too, and whether “lifetime” means yours, the home’s or the product’s.

Repairs over the years

A shutter gets knocked by furniture, pets and vacuum cleaners. On solid wood, a dent or chip is filled, sanded and touched up, because the wood under the paint is the same as the wood on top. On a coated core, a chip that reaches the core is harder to hide, and on MDF it’s the spot where water can get in^[8]. Ask a composite seller how they handle a damaged louver: a touch-up kit, a replacement louver, or a whole new panel.

Where composite honestly wins

• Price. It’s usually the cheaper option, and for a rental or a room you rarely use that can be the right call.
• A waterproof version, where one is offered. A composite sold and warranted as waterproof beats wood in a wet room. Check that the warranty says so.
• Uniformity. No grain variation from one panel to the next, if you don’t want any.

Why we only use solid wood

Every Shutter Boys shutter is American poplar, a hardwood that’s been used for painted moulding, trim and interior doors for generations; Purdue University notes it “is easily painted and tends to hold paint well”^[5]. Solid wood is the same all the way through, so a scuff can be sanded and touched up, and the whole shutter can be repainted. Our wood shutters