Deck builders in Lake County, IL

Lake County has about 270,618 homes, with a median construction year of 1983 (the Illinois median is 1971). Within our covered ZIP codes — about 120,530 homes — the median is 1982, close to the county as a whole.

Homes in the covered parts of Lake County have a median construction year of 1982, so a deck original to a typical house would now be about 44 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: Highland Park (1963), Highwood (1969) and Deerfield (1974). In these communities, expect retrofit decks on older houses and aging decks that need structural inspection, ledger and flashing upgrades, or replacement. Newest housing: Vernon Hills (1991), Lincolnshire (1991) and Island Lake (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 Mundelein 4 Wsw, about 2 miles away. It records an average of 140 days a year with a low at or below 32°F — a long, hard freezing season. On roughly 86 of those days the temperature climbs back above freezing, so water in wood, soil and gaps between boards repeatedly freezes and thaws.

For Lake 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.

Snow is a major factor: the Mundelein 4 Wsw station averages about 43.1 inches a year. Framing has to carry snow load, stairs need a plan for winter use, and snow removal should be done with plastic-bladed shovels and ice-melt products the decking manufacturer allows.

Precipitation averages about 38.5 inches a year, falling on about 73 days with 0.1 inch or more — wet enough that drainage and flashing still matter, but dry spells also let wood surfaces dry out and check in the sun.

Summer heat is mild by comparison — average summer highs near 80°F and only about 11 days a year at 90°F or above — so board color can be chosen mostly on looks.

• Replacement and major repair: about 131,444 homes (49%) 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 83,810 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 15,025 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.

67% of Lake County's homes are detached single-family houses and 10% are townhouses or other attached homes; 75% 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.