Window and siding replacement in St. Peters
What the code and the permit desk actually require here — and what the houses in St. Peters tend to be hiding behind the siding.
- People
- 61,398
- Homes
- 24,233
- Size
- 22.47 square miles
- From downtown
- About 30 miles northwest
- ZIP codes
- 63376, 63304, 63303, 63366
- Founded or incorporated
- 1910
St. Peters grew from 486 residents in 1970 to 15,700 by 1980 as St. Charles County suburbanized rapidly; it did not reach city status until 1959 after being a town since 1910.
St. Peters
St. Peters had under 500 residents as late as 1970 and grew to over 60,000 by the mid-2020s; the median house/condo built is 1987, meaning the overwhelming majority of the housing stock is 1970s-onward suburban construction with essentially no pre-suburban core.
What that vintage turns up
First-generation vinyl replacements went in across this whole period and they are now hitting both of the ages that matter at once: the frames are inside the twenty-to-forty-year band and the sealed glass units are well past the eight-to-twenty-year band. That combination produces the most common call we get on houses this age — fogged glass in a frame that is still perfectly sound. The honest first answer there is replacing the glass unit, not the window.
Hardboard and wood-composite lap siding from this era is the one with the paperwork. Masonite's hardboard covered product installed between 1980 and 1998 and reached roughly four million homeowners; Louisiana-Pacific's Inner-Seal siding had its own national settlement in the mid-1990s. Both claim programmes closed years ago, so the relevance now is diagnostic rather than financial: swelling, delamination and mushrooming along the bottom edges of the boards on a house of this age is a known product history, not necessarily the owner having neglected it.
The one to watch on a house of this age
Synthetic stucco applied before about 1997 is the high-risk cohort. Roughly ninety-five per cent of American applications were the face-sealed kind, which has no way to drain what gets past it, and the failures traced back overwhelmingly to flashing that was left out. Drainable systems are a different animal and are not the problem.
Lead paint. No, for anything built after 1978 — but confirm the build year before assuming it. 25.0% of the homes in St. Charles County were built before 1980, and on anything pre-1978 the EPA renovation rule applies to both of these trades. Window replacement is never exempt from it, at any size — a single window triggers it. A whole-house re-side clears the twenty square foot exterior threshold on the first wall. What the rule actually requires of a contractor.
The rules in St. Peters
Siding replacement Permit required
Re-siding is not listed among work exempt from permit. City Code Sec. 504.040(A)(4) replaces IRC R105.2 'Work exempt from permit' in its entirety; the replacement Building list covers detached accessory structures, fences, retaining walls, water tanks, sidewalks, painting, and swimming pools, and contains no exterior-cladding, fenestration, glazing or roofing entry. Under IRC R105.1 as adopted, an alteration or repair not on the exemption list requires a permit.
Window replacement, same opening Permit required Enlarging or cutting an opening Permit required
St. Peters is one of the jurisdictions that does not draw the same-opening / new-opening distinction. Its wholesale replacement of R105.2 (Sec. 504.040(A)(4)) omits window, door and glass replacement from the exemption list entirely, so like-for-like insert replacement is not carved out the way it is in O'Fallon, Cottleville and Jefferson County. Same caveat as siding: derived from the amended code text, not from a published homeowner list. Building Code Compliance page states only that 'Any new construction or alterations to the structural, plumbing, mechanical, or electrical systems require the appropriate City permits.'.
A replacement window here has to be U-0.30 or lower
City Code Chapter 513, St. Peters Energy Conservation Code: 'The International Energy Conservation Code (IECC), 2021 Edition, as published by the International Code Council, Inc., is hereby adopted as the Energy Conservation Code of the City.' Ordinance No. 7912, dated December 21, 2023. Chapter 504 (residential) provides that 'wherever the term International Energy Conservation Code is used, it is deemed to mean St. Peters Energy Conservation Code, Chapter 513.' The City's Building Code Guide page independently lists 'City Code Chapter 513 Energy Conservation Code (IECC 2021).'.
That figure comes from the 2021 edition this jurisdiction has adopted.
A window fitted here must also carry an SHGC of 0.40 or lower.
For comparison, ENERGY STAR asks for U-0.25 or lower with an SHGC of 0.40 or lower everywhere in this metro, which is stricter than every code edition in force here. And the code only bites when the sash and the glazing are replaced together — replace the glass alone in an existing sash, or add a storm window over the top, and it does not apply.
Contractor registration Yes
From the City's 'Opening a Business in the City of St. Peters' guide: 'By Ordinance, no person shall operate a business within the City of St. Peters without first applying for and receiving a business license.' For construction contractors specifically, 'a Certificate of Insurance showing proof of Workers' Compensation or an Affidavit of Exemption for Workers' Compensation is required' before the city business license issues. Workers' comp is mandatory for construction contractors with one or more employees, including LLC members unless a Rejection of Coverage is filed with the Missouri Department of Insurance. No siding- or window-specific trade licence and no bond requirement is published. Licensing Office: 636-477-6600 ext. St. Charles County's own contractor licence list (electricians, plumbers, HVAC, fence, pool, drainlayers, third-party inspectors, blasters) does not cover siding or windows, and the St. Peters guide does not reference the county licence at all.
Local quirks
St. Peters does not publish any consumer-facing 'do I need a permit' list - the Building Code Guide page only names the adopted chapters and warns that 'Codes are changed regularly,' directing callers to the Planning Department at 636-477-6600 ext. It is also the only St. Charles County city in this metro whose amended R105.2 drops the same-opening window/door exemption that O'Fallon, Cottleville and Jefferson County all carry, which makes it materially stricter on pocket window replacement than its immediate neighbours.
Who to call
- Building dept
- 636-278-2244
- Official
- Not published. Any site printing a name here is guessing.
- Permits
- Department page
How St. Peters compares with the rest of St. Charles County
Same county, same climate, same houses. Not the same rules.
| Place | Permit to re-side | Permit for a window | Window must meet |
|---|---|---|---|
| St. Peters | Yes | Yes | U-0.30 |
| Cottleville | Yes | No | U-0.30 |
| Lake St. Louis | Yes | Yes | U-0.35 |
| O'Fallon | No | No | U-0.30 |
| St. Charles | No | Not published | U-0.35 |
| Wentzville | Yes | Yes | U-0.40 |
Work we have done in St. Peters
None logged in St. Peters yet. When there is one it goes here, with the address block and what was actually done to it. An empty section is better than a number you cannot check.
Where these facts came from
Everything on this page about St. Peters was read off a published source. Where a question has no published answer we have said so rather than filling the gap.
Sources: stpetersmo.net · stpetersmo.net · ecode360.com · ecode360.com · ecode360.com · stpetersmo.net
Windows or siding in St. Peters?
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