Deck builders in Lemont, IL

The median home in Lemont was built around 1992. A deck built with a house of that age is now about 34 years old — the stage where first-generation pressure-treated decks commonly need major repair or replacement.

Decks built before 2004 were very likely made with CCA-treated lumber, which was phased out of most residential uses at the end of 2003. That doesn't make an existing deck unsafe, but old boards shouldn't be burned, and demolition debris should be disposed of according to local rules.

That makes Lemont's housing 31 years newer than Cook County as a whole, where the median home was built in 1961. Statewide, the median Illinois home was built in 1971. Among the 102 covered Illinois communities with Census data, Lemont ranks #95 for oldest housing. In this ZIP code, 13% of homes were built before 1960, 19% between 1960 and 1979, 38% between 1980 and 1999, and 30% since 2000 — the single largest group dates to the 1990s.

The nearest NOAA climate station with 1991–2020 normals is Little Red School Hse, about 6 miles away. It records an average of 131 days a year with a low at or below 32°F — a substantial freezing season. On roughly 94 of those days the temperature climbs back above freezing, so water in wood, soil and gaps between boards repeatedly freezes and thaws.

For Lemont, 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 Lemont is about 33.2 inches a year (Romeoville WFO). That's enough that shoveling and ice-melt choices affect deck surfaces, and stair treads benefit from good texture and drainage.

Lemont sees about 41.4 inches of precipitation a year, with measurable rain or snow (0.1 inch or more) on about 78 days. Good drainage between boards, clean gaps and a ledger that is properly flashed keep that water from rotting the frame.

Summers are hot: average summer highs are near 87°F, with about 45 days a year reaching 90°F or more. Surface temperature is a real consideration — lighter board colors, shade from the house or a pergola, and heat-mitigating composite lines are worth comparing.

Other Lemont factors: about 45 days of 90°F+ heat make board color and surface temperature important. Budget, upkeep tolerance and sun exposure on your particular lot still decide the final choice between these options.

Lemont has about 9,090 housing units across its covered ZIP code. 78% are single-family detached homes, 11% are attached homes such as townhouses and rowhouses, and about 10% are in buildings with two or more units. Roughly 87% of occupied homes are owner-occupied.

Detached single-family homes dominate in Lemont, so most decks are backyard decks attached to the rear of the house. That gives more freedom on size, layout and stairs, and makes a well-planned deck one of the most-used rooms of the home.

• Replacement and major repair: about 4,538 homes (50%) 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 1,812 homes (20%) 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 1,050 homes (12%) 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.

Lemont has a defined building season. Spring and early fall offer the most comfortable working weather; winter is a good time to settle the design and apply for permits. Stains and sealers generally need dry weather and moderate temperatures, so plan wood finishing for late spring or early fall.

For Lemont, IL, ask the permit office whether your deck needs a permit based on its size, height and attachment to the house, which drawings and inspections are required. Statewide code background for Illinois is on our state page; local rules change, so the building department remains the authority.

The closest covered area is Darien, about 4.8 miles from the center of Lemont's covered ZIPs. Its median home was built in 1978, 14 years earlier than in Lemont. Lemont has 16 percentage points more detached single-family homes (78% vs. 63%), which changes how many projects are backyard decks versus compact townhouse decks. Owner-occupancy is 87% in Lemont compared with 80% in Darien. Lemont's covered ZIP code span about 29.7 square miles of land with roughly 9,090 homes — about 306 per square mile, a low density that usually allows larger decks and freestanding designs.