I recently gutted my basement in an early 1900s home that was finished in the mid-80s, and discovered a window! This window is directly under my front door, hidden by a deck that I've never really looked under in detail, so I've never noticed the window. The window is about a foot above grade, and again, covered by a deck, so it is not exposed to snow/rain.

I'm debating what to do with this, all my other windows are upgraded to newer windows about 4 years ago, but this is still a single-pane old-style window. I'm not sure if I should remove it and try and block it in with cinder blocks (Foundation is an old poured foundation), or is it acceptable to leave it as long as it's insulated and sealed? (I'd probably also cover the exterior of the Window with XPS and pressure treated plywood or something similar) The previous basement had fiberglass insulation, vapour barrier then drywall right over it, which I know won't cut it. My plan for finishing is hanging XPS boards directly against the concrete, sealing all the seams, spray-foaming any gaps around the boards, then 2x4 studs and Roxul batts as insulation. The R7.5 from XPS, plus R14 from Batts should give me approximately R22.5, which should be plenty.

Any advice? I know the "Best" thing would be to remove it, but is it acceptable to cover up a window should anyone ever find a need for it?

I've marked the "Answer" as to leave it. Excellent discussion for and against removing the window, but as mentioned, I think I'll leave it, insulate it and cover it from the outside. Who knows what other problems removing it could cause.


  • 1
    If you cover it up, will anyone ever find it again?
    – Brilliand
    Commented Jul 17, 2014 at 18:43
  • I am not sure I would cement it up. I doubt the cement you put in will be as leak proof as the window that is in there. Leave it and it is an option later on. If anything board it on the outside so an animal doesn't break in and make a nest there.
    – DMoore
    Commented Jul 17, 2014 at 22:44
  • Are you sure you want to cover it up? If you are considering having a bedroom in the basement, usually (most jurisdictions) there is a requirement for a window as emergency escape.
    – wallyk
    Commented Jul 18, 2014 at 2:06
  • The window is under the "front deck" - can one actually escape from under that deck? If not the emergency exit point is moot. Commented Jul 18, 2014 at 10:36

3 Answers 3


Unless the existing window is leaking, the sole criterion for judging better and worse options in this case is the likelihood of future bulk water infiltration.

The current installation is performing functionally and aesthetically as part of the building envelope. Breaching and patching the envelope is not a repair, and at best will only perform equally well with the current situation in regard to the prevention of bulk water infiltration.

From an insulation standpoint, the cost benefit analysis should factor thermal performance based on the weight of an empirically proven installation versus untested new construction and the requirement that the new construction must occur under less than ideal conditions (i.e. under a porch).

The existing window wasn't a problem a year ago. It isn't a problem now. It is unlikely to be a problem a year from now.

  • In addition to thermal, there is the question of how long the wood (I presume) window structure will hold up. Yes, I know, I've got 100-plus-year-old window frames in my basement and they've mostly held up. On the other hand, the wood seems to have shrunk a bit, and thermal cycling hasn't been remarkably kind to the glazer's putty, and... It may not be a problem a year from now, but I'm not sure how much longer I'd give it before it at least needs active maintenance.
    – keshlam
    Commented Jul 18, 2014 at 1:44
  • Based on the question, the alternatives to a possible straightforward window maintenance issue are: pulling the envelope apart to the point where the alteration can be done properly with no way of knowing how far apart the wall must be taken until it's apart or to do something that might work. Reglazing a window is an intermediate DIY job of nominal cost. Disassembly and leak-proof modification of a 100 year old building is likely to require more expert judgement, incur more cost and create additional scope on an interior renovation.
    – user23752
    Commented Jul 18, 2014 at 2:32
  • Granted. On the other hand, if you're going to modify a 100-year-old building, it might make sense to do so with the intent of having the modification last another 100 years, or at least not having some future buyer's inspector notice the window and possibly express concern about it. I see your point, but I can argue it either way.
    – keshlam
    Commented Jul 18, 2014 at 2:34
  • An original window is less likely to influence a sale than a dubious infill, and the infill probably adds nothing to sale price and 100 year solutions can be expensive. I'd put it this way, the homeowner gutted a room and discovered a can of worms buried in the wall. My suggestion is to avoid removing the lid. I am inclined away from seeing how many worms the can holds. In my experience old buildings are often worms all the way down
    – user23752
    Commented Jul 18, 2014 at 2:58
  • Can't argue with that. :-)
    – keshlam
    Commented Jul 18, 2014 at 3:01

There's no problem per-se with covering it up. However, with a windows there's lots of chances there for leaks. And since you can't see the window from the outside and it will be behind a wall inside, you probably won't be able to see any evidence of damage or leaks until it's too late and caused significant damage to your new walls and flooring.

Based on the amount of work you plan on doing to the rest of the basement, knocking out the window and frame and filling it with concrete is not that big of a job.


If you just bury it, it's a potential leak and/or maintenance hassle waiting to bite you later. And hiding it makes noticing, finding, and fixing the problem harder when that happens.

I have several windows under my own porch (with security bars, which I consider absolutely necessary in that situation!), and am seriously considering closing them off permanently myself. They really aren't delivering any significant amount of light, they aren't useful for ventilation, all they are as far as I'm concerned is thin/leaky/weak sections of wall.

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