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Window Sealing in St. Louis — Caulking & Re-Glazing to Stop Drafts

Failed glazing compound and caulk are the most common causes of drafty windows in St. Louis homes — and the most overlooked.


Window Sealing in St. Louis


The two window sealing services FIX St. Louis handles are re-glazing (restoring the glazing compound that seals glass into single-pane wood window sashes) and caulking (sealing the perimeter joint between the window frame and the exterior wall). Both are common causes of drafts and energy loss in St. Louis homes, particularly in older housing stock. No minimum job size. Phones answered 24/7.

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Window Sealing Services FIX St. Louis Handles

ProblemWhat to Do
Windows that need glazingRemove old dried glazing compound; re-glaze single-pane sash properly; prime and seal.
Windows that need caulkingRemove failed caulk; prepare surface; apply new caulk in correct type for the application.
These services are closely related to window frame repair. When a window frame is being repaired, the sealing should always be addressed at the same visit. A restored frame with failed caulk will begin absorbing moisture again immediately.

Glazing vs. Caulking: Two Different Sealing Problems

Homeowners sometimes use these terms interchangeably, but they are different materials used in different locations for different purposes.

TypeWhere UsedWhat It DoesKey Notes
Glazing compoundSingle-pane wood windowsSeals the glass pane into the wood sash. Dries out and shrinks over 10–20 years. Must be re-applied before painting, or the new paint will fail at the same joints.Apply with a glazing tool; must be primed before painting. Not appropriate for vinyl or aluminum frames.
Paintable latex caulkInterior window trim, inside corner jointsSeals gaps between trim and wall on interior. Flexible, paintable, easy to apply.Most appropriate for interior wood-to-drywall joints and trim gaps.
Elastomeric / silicone exterior caulkExterior window-to-siding/brick jointsSeals the joint between the window frame and the exterior wall surface. Must flex with thermal movement without cracking or losing adhesion.Highest durability. Not paintable in all formulations — check before applying. Required on the exterior perimeter.

Dr. Steve’s Take:

Dr. Steve dedicated an entire column to drafty windows and doors in St. Louis — specifically, how to identify where the air is actually coming from and fix the right thing. Caulking is among the top recommendations. A $10 tube of the correct exterior caulk applied in the right places can make a measurable difference on a January energy bill.

From Dr. Steve’s Tips: Maybe That’s Why Your Home is as Drafty as a Flight on Alaska Airlines

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Why Window Sealing Matters More Than Most Homeowners Realize

The Drafty Window Problem in St. Louis

A window that allows air infiltration in winter is costing money on every energy bill from November through March. The U.S. Department of Energy estimates that drafty windows and doors account for 25–30% of residential heating energy use. In St. Louis, where winters can be genuinely cold and heating costs are real, this is a meaningful number.

The draft is almost never coming through the glass. It is coming around it — through failed glazing compound between the glass and the sash, through gaps at the joint between the window frame and the exterior wall, or through deteriorated weatherstripping between the sash and the frame.

Re-Glazing: The Forgotten Maintenance Task

Glazing compound — the putty-like material that holds the glass pane in a wood window sash — has a service life of 15–25 years before it dries, shrinks, and begins pulling away from the glass or the wood. When it does, it creates a gap that allows air infiltration, allows water to enter behind the glass and into the sash wood, and creates a paint adhesion failure line.

Re-glazing is a routine maintenance task on wood window sashes that most homeowners have never heard of. In St. Louis, where older housing stock with original wood windows is common — particularly in Kirkwood, Webster Groves, Maplewood, and Brentwood — glazing compound failure is one of the most common causes of both drafty windows and sash rot. The two problems are directly connected: failed glazing allows moisture in, and moisture causes rot.

Dr. Steve’s Take:

Eco-friendly home repair is not always about installing new products. Dr. Steve pointed this out in a column on small fixes that reduce a home’s carbon footprint: sealing drafts and air gaps is the single highest-impact thing most St. Louis homeowners can do. Re-glazing and caulking cost very little and can meaningfully reduce heating energy use.

From Dr. Steve’s Tips: Eco-Friendly Repairs: Tiny Fixes to Reduce a Home’s Carbon Footprint

The Right Caulk in the Right Place

One of the most common caulking mistakes is applying the wrong product for the location. Interior paintable latex caulk on an exterior joint fails within a season — it is not designed to withstand the thermal movement and UV exposure of an exterior joint. Exterior elastomeric or silicone caulk in an interior trim joint is harder to work with than necessary. Getting the product right for the application is part of doing the sealing correctly.

We also address surface preparation before caulking — which means removing the old failed caulk completely rather than caulking over it. Caulk applied over old caulk fails faster, looks worse, and does not seal the joint properly.

Dr. Steve’s Take:

Dr. Steve covered cold-weather preparedness in a column specifically about winning the cold war against air infiltration — the recommendation is to address exterior caulk and weatherstripping in the fall before temperatures drop. That is the window when caulk needs to cure before freeze-thaw cycles test it. Don’t caulk in temperatures below 40°F.

From Dr. Steve’s Tips: Next Time, WIN the Cold War. Be a HERO at ZERO!

314-434-4100

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FAQs

Window Caulking & Glazing in St. Louis

Drafty Windows? Failing Caulk? Fix It Before Winter.

Window sealing is one of the highest-return repairs a St. Louis homeowner can make — low cost, immediate impact, measurable energy savings. Firm quote before we touch anything. No minimum job size. Phones answered around the clock.

Contact FIX St. Louis — Window Services

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