Looking for an addition contractor in Weldon Spring, MO? Describe your project once and up to three addition contractors who work in Weldon Spring and St. Charles County get back to you with a quote. It's free and there is no obligation.
Weldon Spring is home to about 5,304 people (2024 Census Bureau estimate), a stable community (−0.5% since 2020). With 694 people per sq mi, it is a semi-rural area. Growing families here often add space instead of moving.
Weldon Spring at a glance
- Population (Census Bureau estimate, 2024)
- 5,304 (−0.5% since 2020)
- Rank in Missouri
- 130th of 938 cities and towns
- Land area
- 7.6 sq mi
- Population density
- 694 people per sq mi (semi-rural)
- Type
- City (Weldon Spring city)
- Main county
- St. Charles County
What to check before hiring in Weldon Spring
- Zoning: check Weldon Spring's setbacks, lot coverage and height limits first.
- License and permit: in Missouri, additions are built by licensed contractors under a permit.
- Structure: second stories need an engineer to check the existing house.
- Price drivers: size, foundation, roof tie-in, plumbing and finishes.
Useful official resources
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ICC: International Code Council
Official information and guidance.
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NAHB
Official information and guidance.
Services available in Weldon Spring
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Room addition
Ground-floor addition with foundation, framing, roof and finishes.
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Second-story addition
New floor over the existing house, with structural engineering.
Frequently asked questions in Weldon Spring
How much does an addition cost in Weldon Spring, MO?
It depends on size, foundation and finishes. Describe your project: contractors who serve Weldon Spring reply with a quote.
How long does it take?
Often a few months, plus design and permits.
Does an addition raise property taxes?
Usually, since it increases the assessed value.
Which addition contractors will contact me?
Up to three independent addition contractors who serve Weldon Spring and the surrounding area, chosen for the service you need. Your details are shared only with your consent.
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2024) and Gazetteer Files (public domain), imported on 10/31/2026. Figures describe the incorporated place or county as published; they are shown for information only.