How old are homes in Montgomery County, and what does that mean for decks?
The median home in Montgomery County was built in 1971; 37% predate 1960 and 17% were built since 2000.
Montgomery County has about 350,351 homes, with a median construction year of 1971 (the Pennsylvania median is 1965). Within our covered ZIP codes — about 312,923 homes — the median is 1970, close to the county as a whole.
Homes in the covered parts of Montgomery County have a median construction year of 1970, so a deck original to a typical house would now be about 56 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.
| Decade built | Homes | Share |
|---|---|---|
| 2020 or later | 5,296 | 2% |
| 2010s | 22,976 | 7% |
| 2000s | 29,987 | 9% |
| 1990s | 37,867 | 11% |
| 1980s | 40,033 | 11% |
| 1970s | 42,462 | 12% |
| 1960s | 40,924 | 12% |
| 1950s | 55,812 | 16% |
| 1940s | 19,038 | 5% |
| before 1940 | 55,956 | 16% |
Which Montgomery County communities have the oldest and newest homes?
Among covered Montgomery County communities, Merion Station has the oldest housing (median 1938) and Colmar the newest (median 2002).
Oldest housing: Merion Station (1938), Narberth (1945) and Glenside (1951). In these communities, expect retrofit decks on older houses and aging decks that need structural inspection, ledger and flashing upgrades, or replacement. Newest housing: Colmar (2002), Skippack (1994) and Collegeville (1993). Here, projects lean toward enlarging builder-installed decks, adding stairs and railings, and upgrading to low-maintenance boards.
How does Montgomery County's climate affect deck building?
Covered parts of Montgomery County average about 92 days a year at or below freezing (NOAA 1991–2020 normals, 8 stations). Across the covered communities, nearby stations range from about 62 to 137 freezing days a year, so conditions differ noticeably between Montgomery County's higher, more rural areas and its urban core.
The nearest NOAA climate station with 1991–2020 normals is Willow Grove Nas. It records an average of 92 days a year with a low at or below 32°F — a moderate number of freezing nights. On roughly 76 of those days the temperature climbs back above freezing, so water in wood, soil and gaps between boards repeatedly freezes and thaws.
Frost is less severe in Montgomery County than in northern states, but footings still have to meet the local frost-depth requirement, and freeze-thaw cycles are enough to work loose nails and open checks in unsealed wood.
Average snowfall near Montgomery County is about 25.3 inches a year (Norristown). That's enough that shoveling and ice-melt choices affect deck surfaces, and stair treads benefit from good texture and drainage.
Montgomery County sees about 50.7 inches of precipitation a year, with measurable rain or snow (0.1 inch or more) on about 86 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 22 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.
What deck projects are most common in Montgomery County?
Based on the age of Montgomery County's housing, the largest group of projects is likely to be retrofitting or rebuilding decks added to older homes.
- Retrofit decks on older homes: about 171,730 homes (49%) predate 1970. Here the priority is confirming that add-on decks are properly attached — or rebuilding them freestanding — before any cosmetic work.
- Replacement and major repair: about 120,362 homes (34%) 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.
- Upgrades and expansions: about 28,272 homes (8%) 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.
Which Montgomery County communities do you serve?
46 communities in Montgomery County have covered ZIP codes. Only the ZIPs listed are covered.
| Community | Covered ZIPs here | Median year built | Detached homes |
|---|---|---|---|
| Norristown | 19401, 19403 | 1970 | 36% |
| Abington | 19001 | 1955 | 71% |
| Ambler | 19002 | 1973 | 60% |
| Bala Cynwyd | 19004 | 1960 | 52% |
| Blue Bell | 19422 | 1984 | 57% |
| Bridgeport | 19405 | 1962 | 23% |
| Bryn Athyn | 19009 | 1970 | 70% |
| Collegeville | 19426 | 1993 | 67% |
| Colmar | 18915 | 2002 | 39% |
| Conshohocken | 19428 | 1968 | 24% |
| Dresher | 19025 | 1985 | 68% |
| Elkins Park | 19027 | 1954 | 44% |
| Flourtown | 19031 | 1958 | 67% |
| Fort Washington | 19034 | 1968 | 66% |
| Gladwyne | 19035 | 1968 | 83% |
| Glenside | 19038 | 1951 | 70% |
| Gwynedd | 19436 | 1969 | 4% |
| Gwynedd Valley | 19437 | 1982 | 74% |
| Harleysville | 19438 | 1988 | 61% |
| Hatboro | 19040 | 1958 | 64% |
| Hatfield | 19440 | 1978 | 51% |
| Horsham | 19044 | 1979 | 36% |
| Huntingdon Valley | 19006 | 1967 | 73% |
| Jenkintown | 19046 | 1954 | 51% |
| King Of Prussia | 19406 | 1977 | 33% |
| Lafayette Hill | 19444 | 1975 | 61% |
| Lansdale | 19446 | 1978 | 45% |
| Merion Station | 19066 | 1938 | 77% |
| Mont Clare | 19453 | 1958 | 23% |
| Montgomeryville | 18936 | 1978 | 0% |
| Narberth | 19072 | 1945 | 52% |
| North Wales | 19454 | 1985 | 48% |
| Oaks | 19456 | 1957 | 90% |
| Oreland | 19075 | 1953 | 92% |
| Plymouth Meeting | 19462 | 1966 | 66% |
| Pottstown | 19464 | 1966 | 57% |
| Royersford | 19468 | 1992 | 40% |
| Schwenksville | 19473 | 1989 | 73% |
| Skippack | 19474 | 1994 | 56% |
| Souderton | 18964 | 1973 | 52% |
| Spring House | 19477 | 1975 | 100% |
| Willow Grove | 19090 | 1961 | 61% |
| Worcester | 19490 | 1984 | 100% |
| Wyncote | 19095 | 1961 | 39% |
| Wynnewood | 19096 | 1953 | 63% |
| Zieglerville | 19492 | 1981 | 35% |
What decking material works best in Montgomery County?
Capped composite is a strong default for Montgomery County because about 76 freeze-thaw days a year are hard on unsealed wood and many elevated townhouse decks are hard to reach for re-staining.
53% of Montgomery County's homes are detached single-family houses and 20% are townhouses or other attached homes; 71% of occupied homes are owner-occupied. The sizable townhouse share means many elevated rear decks where re-staining is awkward, which tilts the value toward composite or PVC.
Who issues deck permits in Montgomery County?
It depends on where you live: incorporated cities and towns in Montgomery County usually run their own permit offices, while unincorporated areas are typically served by Montgomery County.
Pennsylvania's Uniform Construction Code applies statewide and is enforced by municipalities or third-party agencies they designate. Contact your township or borough. 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.

