Window and siding replacement in Lake St. Louis
What the code and the permit desk actually require here — and what the houses in Lake St. Louis tend to be hiding behind the siding.
- People
- 16,707
- Homes
- 7,422
- Size
- 9.35 square miles
- From downtown
- About 34 miles northwest
- ZIP codes
- 63367
- Founded or incorporated
- 1975
The community is built around two private lakes owned by the Lake St. Louis Community Association; not all residents have lake-access membership. It faced annexation pressure from O'Fallon (east) and Wentzville (west) before incorporating.
Lake St. Louis
A planned lake community developed from initial 1961 planning and 1975/1977 incorporation onward.
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.
Neighbourhoods
We work across Harbor Town and The Meadows at Lake St. Louis.
Next door
Lake St. Louis shares a boundary with O'Fallon, MO and Wentzville. Where we have a page for a neighbour it is linked; where we do not, the rules there are still different from the rules here.
The rules in Lake St. Louis
Siding replacement Permit required
Re-siding is not listed among work exempt from permit. City Code Sec. 500.010 revises IBC 105.2 and IRC R105.2 and the amended Building exemption list is only four items: '(1) Retaining walls that are not over four (4) feet (1,219 mm) in height. Under IRC R105.1 as adopted a permit is therefore required.
Window replacement, same opening Permit required Enlarging or cutting an opening Permit required
The amended R105.2 list (four items, quoted above) contains no window, door or glass-replacement exemption, so Lake St. Louis draws no same-opening / new-opening distinction and a permit is required either way under R105.1. Corroborating signal: the City's Building Permits page publishes project-specific permit guides including one for 'asphalt roofing,' i.e. even reroofing is permitted here, unlike O'Fallon and Jefferson County. Same caveat: no plain-language city statement on windows.
A replacement window here has to be U-0.35 or lower
Lake St. Louis adopted the 2021 family of I-Codes (IBC, IRC, IFC, IPC, IMC, IFGC, IPMC, ISPSC, IEBC) plus the 2020 NEC, but deliberately held the energy code back a generation. Sec. 500.010(A)(1) names 'the International Energy Conservation Code, 2015 Edition,' and Sec. 500.010(A)(3)(a)(2) amends the adopted codes so that 'All references to the 2021 International Energy Conservation Code are replaced with reference to the 2015 International Energy Conservation Code' (Ord. No. 4726, 1-21-2025). This is an express, recent and deliberate rollback of the energy code only.
That figure comes from the 2015 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
Building Permits page: 'All individuals or companies offering their services for hire and/or engaging in construction activities within the corporate limits of the City of Lake Saint Louis are required by Lake Saint Louis Municipal Code to obtain a City Business License prior to engaging in construction activities.' The Building Division page repeats it as 'Contractors Business License Required for All Contractors.' No trade carve-out, so siding and window contractors are covered. No fee, bond or insurance amount is published on either page.
What the permit costs
Sec. 109.2 (IBC) and R108.2 (IRC) as adopted: 'The fees for all permits shall be as indicated in the Lake Saint Louis Municipal Code.' Sec. 109.2.1 / R108.2.1 handle plan review fees the same way. The page says a current fee schedule exists but the amounts were not published on any page reached.
Local quirks
Lake St. Louis also permits asphalt roofing (a dedicated permit guide exists), which is the opposite of the O'Fallon and Jefferson County reroofing exemptions a few miles away. Permit technician for pre-checking whether a job needs a permit: Michelle Debord, 636-625-7937, mdebord@lakesaintlouis.com.
Who to call
- Building dept
- 636-625-7984
- Official
- James Hoeltge, Chief Building Official (636-625-7984, jhoeltge@lakesaintlouis.com)
- Permits
- Department page
How Lake St. Louis 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 |
|---|---|---|---|
| Lake St. Louis | Yes | Yes | U-0.35 |
| Cottleville | Yes | No | U-0.30 |
| O'Fallon | No | No | U-0.30 |
| St. Charles | No | Not published | U-0.35 |
| St. Peters | Yes | Yes | U-0.30 |
| Wentzville | Yes | Yes | U-0.40 |
Work we have done in Lake St. Louis
None logged in Lake St. Louis 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 Lake St. Louis was read off a published source. Where a question has no published answer we have said so rather than filling the gap.
Sources: lakesaintlouis.com · lakesaintlouis.com · ecode360.com · ecode360.com
Windows or siding in Lake St. Louis?
Tell us the address. We look up what the city requires before we work out a price.
Tell us about the house
We answer the phone. If we miss you, we call back.