How Engineered Wood Siding Holds Up in Illinois Weather

What treated strand engineered wood siding is made of

The core starts as thin wood strands blended with resin binders and wax, then pressed under heat into a dense board with an embossed face. A primer or factory finish goes on top. LP Building Solutions treats the strands in its SmartSide products with zinc borate as part of what it calls the SmartGuard process, aimed at fungal decay and termites. Our LP SmartSide page covers the individual lap, panel and trim products.

The untreated hardboard and strand sidings on many houses built in the 1980s and 1990s suffered widespread moisture damage and led to large class-action lawsuits. Today’s treated strand siding is a different formulation, but the lesson of that era still applies: keep engineered wood sealed and keep it off the ground.

Hail, mower stones and dents: how the strand core takes a hit

A strand core flexes and compresses where a cement board would crack. In practice, a baseball, a stone thrown by a mower or a hailstone tends to leave a dent rather than a split board. A dent in an intact paint film can often be filled and touched up instead of replacing the board, and LP promotes SmartSide on that toughness.

That doesn’t make it immune. Very large hail will still dent the face, and a storm-facing wall covered in dents can have small breaks in the paint that let water in. After a significant storm, look closely at the walls that faced the wind and seal any opened spots before winter.

Prefinished or primed: choosing how the boards get painted

Engineered wood siding ships either primed, for painting on site, or prefinished. LP sells its own factory finish as SmartSide ExpertFinish in a set palette, and independent prefinishers also paint LP boards to order. Prefinished boards arrive with even coverage and go straight onto the wall; crews then seal cuts and nail heads with matching touch-up paint. Primed boards allow any color, but they must be painted with a quality exterior acrylic within the period LP specifies after installation, and the result depends on the painter.

Either way, the paint film is part of the moisture protection, not decoration. Failing paint on engineered wood is a maintenance item, not a cosmetic one.

Installation rules that keep engineered wood dry

• Clearances: keep the bottom edge well above soil and mulch (LP’s instructions call for about six inches) and leave a gap above roofs, decks, patios and driveways so boards never sit in water.
• Nailing: heads snug to the surface, never countersunk. An overdriven nail breaks the strand face and has to be sealed.
• Joints: butt joints gapped and sealed the way the instructions specify, or backed with joint flashing.
• Edges: every field cut primed or painted before or right after it goes up.
• Flashing: head flashing over windows and doors, and kick-out flashing where roofs meet walls.

These rules overlap with those for fiber cement siding, but engineered wood is less tolerant of a missed one because wet wood strands swell. See how the two compare in our siding comparison.

Where engineered wood siding fits, and where it doesn’t

Engineered wood fits homeowners who want the look of painted wood lap siding, better impact resistance than vinyl, and less weight and labor than fiber cement. It suits wide, uninterrupted walls where long boards keep seams to a minimum, garages and additions matched to existing wood siding, and exterior trim that pairs with other cladding. It is a weaker choice on walls that stay damp, such as a shaded side yard with sprinkler overspray, or for owners who won’t keep up with painting. Our siding services page explains how a residing project is scoped.

How it handles Chicago-area weather

Care and maintenance

Inspect paint and caulk every spring. Focus on the lowest course, boards just above roof lines and decks, butt joints, and the trim around windows, since those are the places where water finds raw wood fibers. Recaulk open joints with a paintable exterior sealant and touch up chips before winter. Keep sprinkler heads, mulch beds and shoveled snow away from the bottom edge. Repaint when the film starts to chalk or wear thin, which usually happens first on the south and west walls.

Engineered Wood Siding: common questions

How is engineered wood siding different from fiber cement?

Engineered wood is lighter, cuts like lumber, and dents instead of cracking. Fiber cement is noncombustible and less affected by water at its edges. Both need sealed cuts, correct clearances and maintained paint.

Does engineered wood siding attract termites or carpenter ants?

The strands are treated to resist termites and fungal decay, which helps a great deal. Keeping mulch and soil away from the bottom edge still matters, because damp wood near the ground invites insects of all kinds.

Can engineered wood siding be installed in cold weather?

Yes. Unlike vinyl it doesn’t turn brittle, so it can be cut and nailed in the cold. Paint and caulk are the limit: most exterior paints list a minimum application temperature, so primed boards hung in winter may wait for spring paint within the manufacturer’s allowed window.