I noticed with recent rainfalls that we had pools of water on the floor under the radiators placed under our windows (these are not in use any longer - we have HVAC installed in our home).

The window in question. The plastic window casings were removed for cleaning but were installed right back (and to check for drain holes -- there don't seem to be any)

I checked to see if there were any drain holes on these windows that may have been clogged but I don't believe these have them (as I could not find them anywhere -- just the top portion of the windows have holes where I see water drip down).

No weep hole entries that I can see, even when opening the screen

We heard dripping from the radiator and went to look and saw the puddles on the floor. When we moved the curtains, we noticed a bubbling in the plaster walls as well.

plaster bubbling under the window sill

This has definitely been going on for longer than we were initially aware of.

The wooden sill inside of our home was wet as well in the left corner near the window. This part is where we assume the water is at least making its way to (the heighest point that we can see) but cannot figure out the origin.

The corner of the window where we feel it wet on the window sill. A gap can be seen as well in the trim install

I've attached photos of the outside as well where I noticed that the vinyl siding sill has been loosely installed. The vinyl window sill that was loosely installed. The nails came up, the caulk was no longer holding (and poorly done) and the wood underneath is completely soaked. I'm unsure if this is THE problem but certainly A problem.

The soaked wood underneath the loose vinyl sill

I'm not sure where to start... The windowsill outside definitely needs to be installed again but I'm not sure of who to call (window folks seem to only be on-call for replacements not repairs -- these windows were already installed in the home when we purchased 5 years ago).

  • what is your RH? are these metal framed windows? Jan 14 at 3:13
  • Might be better off to just replace that window. Everything looks wrong. Double hung windows are horrible for air leaks. Can't tell but if the frame is metal also terrible for heat transfer and condensation on inside. Is the house 1920ish? You don't have a header flashing and your rough opening isn't properly water proofed. You want a positive drainage plan on your rough sill so if the window leaks the water goes outside. Probably more than one problem. Jan 14 at 3:21
  • @FreshCodemonger the outside pieces are a very thin metal it seems, yes At least the sill and the pieces that cap going down the vertical sides of the windows. The house was built in 1931. Not sure when the siding/windows were done; my guess would be at probably 10 years ago, (we bought the house 5 years ago). We have this setup throughout the house (so far we notice leaks in 4 windows, we have 15 windows in our home.. Jan 14 at 14:46
  • @FreshCodemonger is there any feasibility that putting a healthy amount of sealant on the edges of these sill installs would help with our water issue instead of replacing 15 windows in our home? Definitely an expense we're not looking to make unless necessary (I recognize that leaving things as is may cause further damage so I want to do the right thing here) Jan 14 at 14:52

2 Answers 2


Any company that does home repairs/renovations should be able to handle this. You might find a window installer that will, but it seems unlikely.

Likely tasks that should be done:

  1. remove the interior drywall/plaster
  2. remove the windows as they show damage to the frame and can't be relied on for water intrusion
  3. remove any heavily damaged wood
  4. replace damaged wood
  5. correctly flash the sill
  6. install new windows
  7. appropriately caulk new windows
  8. repair drywall/plaster
  9. paint drywall/plaster

You shouldn't rely on caulking for a seal.

You want positive drainage planes and proper installation. It is unlikely you'll get a lasting repair from fixing up the caulking. You could un-install the window, address the issues and re-install the same window. The older houses tend to be more resistant to water damage, plaster and lath doesn't mold up like drywall and it can take a long time for wood to rot if it has a chance to dry out between wettings.

If I had this issue then I'd wait till the weather is nice and uninstall, fix the issues and re-install and make a determination on the level of effort required for the remaining windows. Chances are someone just hired a window install company last time and this is the install they got so just replacing the windows could end up in the same scenario.

Your biggest issues is the bottom rough opening / sill of the window. The rough opening is unlikely to have a positive drainage slope to the outside and your sill looks to have a moat that encourages water to ingress.

Here is a section view of what you want.

GreenBuildingAdvisor window section

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