Deck builders in DuPage County, IL

DuPage County has about 367,152 homes, with a median construction year of 1978 (the Illinois median is 1971). Within our covered ZIP codes — about 383,113 homes — the median is 1979, close to the county as a whole.

Homes in the covered parts of DuPage County have a median construction year of 1979, so a deck original to a typical house would now be about 47 years old — beyond the point where wood framing, fasteners and flashing can be assumed sound.

Many decks from the 1970s and 1980s were built before today's detailed deck provisions appeared in model codes. Common issues on decks of this age include corroded hangers, posts set directly in soil and ledger boards fastened with nails. Replacement is often the better value than repeated repairs.

Oldest housing: Villa Park (1962), Elmhurst (1966) and Medinah (1969). In these communities, expect retrofit decks on older houses and aging decks that need structural inspection, ledger and flashing upgrades, or replacement. Newest housing: Aurora (1995), Bartlett (1992) and Naperville (1989). Here, projects lean toward enlarging builder-installed decks, adding stairs and railings, and upgrading to low-maintenance boards.

The nearest NOAA climate station with 1991–2020 normals is Lisle-Morton Arboretum, about 2 miles away. It records an average of 144 days a year with a low at or below 32°F — a long, hard freezing season. On roughly 98 of those days the temperature climbs back above freezing, so water in wood, soil and gaps between boards repeatedly freezes and thaws.

For DuPage County, that means footings must bear below the locally required frost depth to avoid heaving, and wood surfaces should be kept sealed so absorbed water doesn't split boards over winter. Synthetic decking tolerates freeze-thaw well but still needs the manufacturer's expansion gaps.

Average snowfall near DuPage County is about 24.3 inches a year (Wheaton 3 Se). That's enough that shoveling and ice-melt choices affect deck surfaces, and stair treads benefit from good texture and drainage.

DuPage County sees about 39.7 inches of precipitation a year, with measurable rain or snow (0.1 inch or more) on about 76 days. Good drainage between boards, clean gaps and a ledger that is properly flashed keep that water from rotting the frame.

Average summer highs reach about 83°F, and around 17 days a year top 90°F. On a deck with full afternoon sun, dark composite can get uncomfortable on those days, so test samples in the sun before choosing a color.

• Replacement and major repair: about 200,190 homes (55%) were built between 1970 and 1999, the age group whose original or early add-on decks are most likely to have worn-out framing, connectors and boards.
• Retrofit decks on older homes: about 112,585 homes (31%) predate 1970. Here the priority is confirming that add-on decks are properly attached — or rebuilding them freestanding — before any cosmetic work.
• Upgrades and expansions: about 20,260 homes (6%) were built since 2010. Their decks are usually sound but small or builder-grade, so enlarging the deck, adding stairs and switching to composite or upgraded railings are common.

58% of DuPage County's homes are detached single-family houses and 12% are townhouses or other attached homes; 73% of occupied homes are owner-occupied. With mostly detached homes, wood remains a practical lower-cost option for homeowners willing to clean and seal on schedule.

Illinois building codes for single-family homes are largely adopted and enforced at the municipal and county level, so requirements differ between suburbs. Contact your village or city building department. Before work starts, confirm with the building department for your exact address whether a permit is required, what drawings and inspections it involves, and whether an HOA must approve the design.