A typical St. Louis basement window opening is around 32 inches wide and 14 to 24 inches tall, and whatever sits in it now is often original to the house. Four styles fit that shape: hopper, slider, awning and casement. Which one you can use comes down to the hole you already have and whether anyone sleeps down there.
This guide covers what to call a basement window when you order one, the four styles that fit these openings, and how to measure yours. Then your foundation, the rules that apply once someone sleeps down there, and what moves the price.
What These Small Windows Are Called
The short, wide unit near the ceiling is nearly always a hopper window, hinged along its bottom rail. Older houses around here also have glass block, which lets daylight through but never opens, and you will hear any small foundation opening called a cellar window.
When a contractor names a style rather than a brand, they are telling you how the sash moves, not what it is made of. All four below come in vinyl, and we fit basement window replacement across the St. Louis metro in every one of them.
We fit ProVia units down there. Their locator lists our showroom and rates us Platinum.
The Four Styles That Fit the Opening
Hopper
Hinged at the bottom, tipping inward from the top. This is the default for a basement because it matches the shape of the hole and nobody has to cut concrete. It pulls air along the ceiling, and you can wipe both faces of the glass from indoors.
The drawback is the sash landing in your room. Keep shelving back from underneath it.
Slider
Two or three panes running left to right on a track. Half the opening stands clear when it is open, and nothing swings into the room, which suits a utility area where the wall in front of the window is already spoken for.
Sliders take the least effort to work. That matters on a window you have to lean across a dryer to reach.
Awning
The same short wide shape as a hopper, hinged the other way up so the sash lifts outward. Rain runs off it instead of in, so ask for this one under a deck, a walkway or a low roof overhang.
It needs clear ground outside, and you clean the outer face from the yard.
Casement
Side hinged, cranking outward like a door. The sash swings entirely out of the way, so a casement gives up almost none of its frame to the opening, and that matters enormously if the room is becoming a bedroom. It is the style most basement conversions end up with.
It almost always needs a bigger hole than the one you have, which is a different project from swapping a sash.
What Size Are Basement Windows?
There is no catalog size, because nobody cut these holes to a catalog. The foundation crew formed them when the walls went in, so they vary street to street and sometimes wall to wall in one house.
Off the shelf you will find roughly 32 by 14, 32 by 16 and 32 by 24 inches. Made to order goes wider and taller in quarter inch steps. Most jobs here end up made to order, which is normal rather than expensive.
Watch the difference between the unit size and the clear opening you actually get through it. A 32 by 24 inch hopper does not give you 32 by 24 inches of hole to climb through, because the frame takes its share and the tipped sash takes more. Ask any supplier for the clear opening figure, not the nominal size.
How to Measure the Opening Yourself
Measure the hole, never the old frame, and write everything to the nearest eighth. I take the same four readings on every basement I walk into, because these openings are rarely square:
- Across the top, across the middle, across the bottom. The narrowest of those three is your width.
- Up the left, up the center, up the right. The shortest of those three is your height.
- From the inside face of the wall through to daylight. That is your depth.
- Corner to corner, both ways. Two different answers mean the foundation has moved, and the unit has to suit the hole as it stands.
Write down what the wall is made of too. That one line changes the price more than the window does, and the next section explains why.
What Your Foundation Is Made Of, and Why It Sets the Price
If the window drops straight into the hole you already have, the wall barely matters. The moment the hole has to grow, it decides everything. Three kinds turn up around here.
Poured concrete. Common in newer subdivisions out toward Florissant, Maryland Heights and St. Charles. A concrete saw cuts it cleanly, the edges stay where you put them, and a header carries the wall above the new span. Predictable work, and the easiest of the three to quote.
Concrete block. Also common in post-war houses. The saw goes through it faster than poured concrete. But the blocks are hollow. Someone has to fill the cut cells and set a lintel across the top before anything else happens.
Limestone rubble or brick. This is the one to know about before you plan a bedroom. Older houses in the city and in places like Webster Groves and Kirkwood often sit on stone laid without courses, so there is no straight line to cut along. The stones come out one at a time and the sides of the opening get rebuilt. It is the slowest of the three by a distance, and the quote reflects that.
You can tell which you have with a flashlight and two minutes. Rectangular units in rows with mortar joints on all four sides are block. A smooth gray face with faint horizontal form lines and the odd tie hole is poured. Irregular pale stones of different sizes, with mortar filling the gaps between them, are rubble.
Does a Basement Window Have to Be an Egress Window?
Only if somebody sleeps in the basement, or will once the work is finished. Storage, laundry and a den with no bed in it are all exempt. It is the first thing I ask about on a basement job, because the answer changes the window, the budget and whether an inspector ever sees the room.
Where a bedroom is involved, Section R310 of the International Residential Code sets a floor the window has to clear. These figures are consistent wherever you look them up:
| Requirement | Minimum |
|---|---|
| Clear height you can climb through | 24 inches |
| Clear width you can climb through | 20 inches |
| Sill height above the floor | 44 inches maximum |
| Operation | By hand, no key, no tool |
| Well outside, if the sill is below ground | 9 square feet, 36 inch projection |
| Ladder in the well | Required once the well is deeper than 44 inches |
Run those against your own measurements and most existing basement openings drop out immediately. A hole 14 inches tall cannot yield 24 inches of clearance however you hang the sash.
The two minimums do not add up to the area on their own, and this trips people up. Twenty inches by 24 inches is 480 square inches, which is 3.3 square feet. Published guidance quotes 5.7 square feet almost everywhere, so at the minimum 20 inch width you need just over 41 inches of height to reach it. There is a relaxation to 5 square feet that applies at and below grade, and even that wants 36 inches of height at a 20 inch width.
The area figure is also the one to be careful with. How that relaxation is drafted has shifted between editions of the code. The towns around St. Louis do not all enforce the same edition, and several add local amendments on top.
So call your own building department before anybody orders a size and ask two things: which edition they enforce, and what they have changed in it. Five minutes on the phone is the difference between signing off a finished basement and taking the drywall back down. That is a town hall question, not a window question, and no national guide can answer it for you, because it changes from one town to the next.
What Does a Basement Window Cost to Replace?
We quote these per opening, not off a rate card, because in one St. Louis house I have measured five basement openings and written down five different widths. Seven things push the number around, and you can spot every one of them yourself before anyone visits:
- How far your hole sits from a stock size
- Whether the hole has to grow, which is the single biggest swing on the list
- What the wall is made of, if it does have to grow
- Whether a bedroom is involved, since that dictates a larger unit and usually a well
- The glass package and the frame you pick
- How awkward the window is to reach, past a furnace or above a finished ceiling
- Whether patching the trim inside and the finish outside is included
Insist that any quote names which of those apply to your house. A bare figure cannot be compared with another bare figure, and two quotes that look 40 percent apart often differ only on the last line.
Is It Cheaper to Do Them All at Once?
Per window, almost always. Showing up, covering the floor, measuring and clearing away afterward costs much the same for one opening as for five, and that overhead divides across everything done on the visit.
Split them up when one has failed and the others are sound, or when a bedroom conversion needs a permit that the straight swaps do not.
When This Is Not Our Job
Three situations where you want somebody else.
- A cracked pane in a sound frame. We fit new units rather than repairing old ones, so that is a glazier’s job.
- A wall that is moving. Stepped cracks through the mortar, a bowed wall or a sill that has dropped is a foundation problem. You do not need a window company yet. Fix the wall first, because a new unit set into a wall that is still moving will not stay square.
- Commercial buildings. ProVia builds the units we fit for residential use only, so a shop or a warehouse is somebody else’s job.
Nothing above tells you what your own town enforces, and none of it replaces somebody putting a tape on the hole. It is written to get you to that conversation already knowing the numbers. You can see finished work on our photo gallery.
Common Questions
Booking Someone to Look at It
Your figures tell you roughly which camp you are in. Confirming it takes someone in the room with a tape. If a bedroom is part of the plan, add a call to your town hall about the code they enforce.
Our St. Louis basement window page sets out the units we fit and what a working day on site includes, and our workmanship carries a 10 year guarantee. Book a free in-home estimate or call 314-277-5952, and we will take the measurements ourselves and put the scope in writing.
