Deck builders in Kennett Square, PA

Homes in Kennett Square 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.

That is about the same as Chester County overall (median 1983). Statewide, the median Pennsylvania home was built in 1965. Among the 120 covered Pennsylvania communities with Census data, Kennett Square ranks #85 for oldest housing. In this ZIP code, 27% of homes were built before 1960, 20% between 1960 and 1979, 28% between 1980 and 1999, and 25% since 2000 — the single largest group dates to the 1990s.

The nearest NOAA climate station with 1991–2020 normals is Avondale 2 N, about 4 miles away. It records an average of 109 days a year with a low at or below 32°F — a substantial freezing season. On roughly 88 of those days the temperature climbs back above freezing, so water in wood, soil and gaps between boards repeatedly freezes and thaws.

For Kennett Square, 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 Kennett Square is about 30.5 inches a year (W Chester 2 Nw). That's enough that shoveling and ice-melt choices affect deck surfaces, and stair treads benefit from good texture and drainage.

Kennett Square sees about 47.1 inches of precipitation a year, with measurable rain or snow (0.1 inch or more) on about 80 days. Good drainage between boards, clean gaps and a ledger that is properly flashed keep that water from rotting the frame.

Summer heat is mild by comparison — average summer highs near 82°F and only about 8 days a year at 90°F or above — so board color can be chosen mostly on looks.

Budget, upkeep tolerance and sun exposure on your particular lot still decide the final choice between these options.

Kennett Square has about 9,253 housing units across its covered ZIP code. 62% are single-family detached homes, 17% are attached homes such as townhouses and rowhouses, and about 21% are in buildings with two or more units. Roughly 71% of occupied homes are owner-occupied.

The mix of detached homes and attached or multi-unit housing in Kennett Square means deck projects range from large backyard decks to compact rear decks on narrow lots. Lot size, neighbors' sightlines and any association rules shape the right design.

• Replacement and major repair: about 3,874 homes (42%) 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 3,094 homes (33%) 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 1,060 homes (11%) 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.

Kennett Square 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 Kennett Square, PA, 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 Pennsylvania is on our state page; local rules change, so the building department remains the authority.

The closest covered area is Unionville, about 2.5 miles from the center of Kennett Square's covered ZIPs. Its median home was built in 1938, 44 years earlier than in Kennett Square. Kennett Square has 31 percentage points fewer detached single-family homes (62% vs. 93%), which changes how many projects are backyard decks versus compact townhouse decks. Owner-occupancy is 71% in Kennett Square compared with 80% in Unionville. Kennett Square's covered ZIP code span about 36.8 square miles of land with roughly 9,253 homes — about 251 per square mile, a low density that usually allows larger decks and freestanding designs.