is there any way to waterproof an existing window without removing siding ? I bought a house a few years ago and just noticed that one of the basement windows had a bit of water come in around the bottom of the frame and dripped down onto a foundation sill during an unusually windy and rainy night. When I checked outside, I noticed that it doesn’t seem to have any sort of channeling or flashing and the siding is simply nearly flush with the window around all edges. I’ve attached some pictures. Note that the person who owned the house previously simply put siding over the previous wood clapboard (though the clapboard itself is sound and shows no signs of rot).

any suggestions on how I can fix this?

 

No, you have to take siding off. Use a Malco Sideswiper to unzip the siding. You need to put a flashing behind the side j channels that directs water out onto the nail fin of the first full piece of siding below the window. That way water coming down the j channels is directed out to the weep holes in the siding asap.

You might also find that there is no housewrap behind the siding.

 

I’m almost certain that there isn’t. I’ve done some siding repair and added a few outdoor outlets. Siding is directly on top of the clapboard. Is that a bad thing?

 

Shedding water is the key to long life.

In a perfect world your sheeting would be covered with a house wrap, that would be tucked around the openings of the windows on all but the top, windows installed and then butyl tape installed around the windows to ensure a continuous water shedding layered system.

Many videos out there give the specific details.

The siding helps but should not be considered the primary sealant.