The wall only comes off once. Do the part behind it right.
Window and siding replacement across greater St. Louis, both sides of the river. We looked up the permit rule, the adopted energy code and the window U-factor that actually applies in every one of the 45 cities and counties we work in — and we publish all of it, including the places where the answer is that nobody publishes it.
Windows and siding are the same job from the outside in
Water gets into a wall at the openings. The flashing that stops it sits behind the cladding, which means the only time anyone can inspect it, correct it or replace it is while the siding is off. That is why we do both, and why we will tell you when doing both at once is cheaper than doing either one twice.
Window replacement
Full-frame and insert, wood, vinyl, fiberglass and clad
- The U-factor and SHGC your city actually requires, not a generic number — we publish it for every jurisdiction
- Full-frame where the opening needs a sill pan and a proper flashing tie-in; insert where the existing frame is sound and square, and we will say which one you have
- Egress checked before the order goes in, because a replacement double-hung that drops into the existing hole very often fails the net clear opening rule
- Safety glazing checked at every location the code names, so tempered glass gets ordered as tempered rather than discovered on installation day
- Failed glass units replaced as glass, when the frame is still good and replacing the whole window would be selling you something you do not need
Siding replacement
Vinyl, insulated vinyl, fiber cement, engineered wood and steel
- The water-resistive barrier replaced, not reused, and lapped in the right order
- Kickout flashing at every roof-to-wall intersection — a ten dollar part, the most-missed detail in the trade, and the reason walls rot invisibly for years
- Window heads and jambs re-flashed while they are reachable
- Sheathing opened and inspected, with rot priced as a change order against the actual area found rather than guessed at up front
- Asbestos-cement testing before anything is disturbed on a house built before about 1980, and an honest conversation about covering versus removing
What these jobs are actually worth
Contractors quote resale return and energy payback selectively. Here is the whole table for the census division Missouri sits in, from the industry's own annual report, including the rows that do not flatter us.
Fiber cement siding is the only one of these that returns more than it costs. Windows are the worst performer on the list, and that lines up exactly with the energy arithmetic: windows are a maintenance and comfort purchase, not an investment.
Sources: jlconline.com · jlconline.com
| Project | Job cost | Resale value | Recouped |
|---|---|---|---|
| Siding replacement, fiber cement | $23,470 | $24,236 | 103.3% |
| Siding replacement, vinyl | $18,907 | $15,365 | 81.3% |
| Window replacement, vinyl | $22,781 | $15,932 | 69.9% |
| Window replacement, wood | $26,149 | $17,897 | 68.4% |
And the energy half of it
Replacing single-pane glass with ENERGY STAR windows saves about $493 a year in this climate zone on EPA's modelling. Replacing older double-pane saves about $253. Do that arithmetic against a real quote before anyone tells you windows pay for themselves.
The full calculation, and the cheaper alternative most companies will not mention →
Missouri has no statewide energy code. Illinois has nothing but.
In Missouri, every municipality adopts its own building and energy code, or does not. Across this one metro that produces at least 6 different legal requirements for the same replacement window, and several places where there is no requirement at all. Cross the river and Illinois fixes one standard for the whole state and forbids any city from making it weaker or stronger.
| One example of each | Adopted energy code | Window has to meet |
|---|---|---|
| Brentwood | 2024 IECC | U-0.28 |
| Kirkwood | 2021 Energy Conservation Code | U-0.30 |
| St. Louis City | 2018 IECC | U-0.32 |
| Unincorporated St. Louis County | 2015 IRC energy provisions (no separate IECC adopted) | U-0.34 |
| Webster Groves | 2015 IECC | U-0.35 |
| Wentzville | 2021 IRC energy provisions, locally amended | U-0.40 |
Every jurisdiction we work in is listed, with its own page and its own sources. See the whole table →
No surprises, because the surprises are predictable
Rot behind siding and a failed egress measurement are not unlucky. They are the two things that turn up on these jobs, so we look for both before you sign anything.
We measure and we look
Net clear opening on every bedroom and basement window against the egress rule. Safety glazing at every location the code names. The roof-to-wall intersections, for a kickout that is missing. The build year, which decides whether the lead rule is on the job.
We look up your city
Permit or no permit, which energy code edition applies, what U-factor that puts on the window, whether the city wants the contractor registered, and whether you are in a historic district that regulates what the window can be made of.
You get a written scope
Including what happens if we open the wall and find soft sheathing — priced per square foot against the area actually found, agreed before we start, rather than discovered as a number on the final invoice.
We do the part nobody sees
New barrier, correct lap order, flashing at every opening and every transition, kickouts installed. Photographed as we go, because once the siding is on you have no way to check and neither does the next owner.
Final walk
Every window operated. Every opening checked. On a pre-1978 house, the lead-safe compliance summary you are owed within thirty days.
What customers say
Credentials
Questions people actually ask
Do I need a permit to replace my siding?
It depends entirely on which side of a city limit the house sits on, and the range in this metro is genuinely wide. St. Louis County lists re-siding among the ordinary repairs that need no permit at all. Edwardsville deleted its entire residential exemption list, so everything needs one. Granite City uses a money threshold. We looked up all 45 jurisdictions we work in — the answers are here, city by city, with the published wording.
How efficient does a replacement window legally have to be here?
Missouri has no statewide energy code, so the number changes at every city limit — we found 6 different U-factor requirements across this one metro, plus places with none at all. Illinois is the opposite: one statewide code, and municipalities are forbidden from making it either weaker or stronger. The full breakdown is here.
Will new windows pay for themselves in energy savings?
Almost certainly not, and anyone telling you otherwise is selling. EPA's own modelling puts the saving at about $493 a year replacing single-pane glass in this climate zone and about $253 replacing older double-pane. Against a real St. Louis job that is a payback measured in decades. Replacement windows are worth it when the windows are failing, when the house is uncomfortable, or when you want the house to look different. As a pure energy investment against a window that still works, the arithmetic does not close. Here is the whole calculation, with sources.
My house is old. Does that change anything?
Yes, and it is the single biggest thing people are not told before work starts. 58.8% of homes in this metro were built before 1980, and on anything pre-1978 the federal lead rule applies to both trades. Window replacement is never exempt from it, at any size. A whole-house re-side blows past the exterior threshold immediately. The firm has to be EPA-certified, a certified renovator has to be on site, and you have to be given the EPA pamphlet before work starts. What that actually looks like on a job.
Do you do both windows and siding, or just one?
Both, and often together, because the two jobs share the part in the middle. The flashing at the head and jambs of every window opening lives behind the siding. Re-siding is the only moment in a house's life when you can get at it. Doing windows first and siding two years later means opening the same wall twice and paying for it twice.
Ready when you are
Tell us the address and roughly what you are looking at. We will tell you what your city requires before we tell you what it costs.
Tell us about the house
We answer the phone. If we miss you, we call back.