# Refreshing weather stripping between window sash and sill



## RustNeverSleeps (Sep 26, 2015)

This is not a big issue, but I was curious if there was a better approach towards weather stripping or better product to use. I have removed all the old weather stripping under the sash as part of repainting the windows, and looking to replace it with new strips.

The windows currently use this narrow vinyl strip (photo 1). It fits into a groove under sash as highlighted by the blue arrow (photo 2) and has a double row of cleats on each side to help provide grip. The best match I could find at my local Lowes store was this tubular vinyl gasket made by Frost King. The tubular part is offset from the rib/fin (not centered) and does not have cleats on each side, so I am not sure it will fit in the grove as securely, causing problems in the future. I believe a wider strip would provide a better seal, but probably harder to find (unless just using some generic tape on seal, which is probably not a good idea either).

Secondary issue in next post...


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## RustNeverSleeps (Sep 26, 2015)

Secondary issue is that many of my window sills have/had mildew issues. I am not sure if the previous home owner painted over some mildew, or if the mildew was able to attack an otherwise quality paint job. Nevertheless, the paint on the sill directly below the sash had some visible mildew and felt a bit tacky. It also made the windows difficult to raise, as if always being painted shut. 

I took the drastic action of using a chemical paint stripper to remove the paint from all the window sills (and then clean and prime). The window in post #1 was open to the outside but protected by porch overhang and had only a little mildew (and probably did not need stripping in comparison). But many of my windows looked like the one attached below. It looked like the mildew was generally attacking and causing pitting along the wood grain pattern, but was most aggressively attacking in a straight line directly underneath the weather stripping (highlighted by the blue ovals). I presume this is because of AC leaking out underneath the sash and causing condensation and thus mildew, but that would not explain why window in post #1 looked so comparatively good, unless it was just built with better tolerances. Whatever the cause, I would like to find a weather stripping approach that would minimize this happening in the future. Whether caused by indoor air leaking out, or outside elements getting in.


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## dd57chevy (Jun 21, 2015)

Not sure on the mildew situation . i think most guys would clean the sills then paint w/mildew resistant paint .

If you _want _to , you could look on Blaine Window Hardware's site for an exact match on the weatherstrip .


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## RustNeverSleeps (Sep 26, 2015)

Thanks for the tip about Blaine Window Hardware. Their website helped me understand that what I should be looking for is called a "Kerf-Mounted/Bulb" type of weatherstripping. My old weatherstripping has lost its resilience, the bulb part is compressed flat and has no spring left.


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## ChuckF. (Aug 25, 2013)

http://absupply.net/ is also good for hard-to-get weatherstripping.


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## RustNeverSleeps (Sep 26, 2015)

Cross posting a similar comment I just made in a different thread about door weatherstripping, following up to a recommendation to use silicon. 

Found this article: Weatherstripping sticks to paint, which may also explain why my windows always felt painted shut. A few times I would raise the windows (after being closed a long time) to find the weatherstripping stuck to the paint on the window sill, instead of being attached to the window sash.

Assuming the author is correct, here is the relevant quote:


> The important thing to know is that the standard vinyl bulb that comes with this type of weatherstrip sticks to the latex enamels that most people use today. It doesn’t make any difference how long the paint dries, the vinyl bulb interacts with the latex paint (especially during warm weather), sticks to it and peels off the paint that it touches. It’s this vinyl bulb that causes the sticking.


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## DonnaPal (Nov 4, 2015)

Look for a bulb weatherstripping that is made of Santoprene. Santoprene is a material that is known to help prevent paint sticking to the weatherstripping in hotter climates. For your particular window, see SWISCO’s bulb weatherstripping #58-053


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## RustNeverSleeps (Sep 26, 2015)

DonnaPal said:


> Look for a bulb weatherstripping that is made of Santoprene. Santoprene is a material that is known to help prevent paint sticking to the weatherstripping in hotter climates. For your particular window, see SWISCO’s bulb weatherstripping #58-053


You must have been reading my mind. I was looking at that specific item online and trying to better understand what was this Santoprene material. I think my existing bulb is a little shorter (maybe only 1/4" vs this 5/16") but there is enough slop in the window movement up/down now that the old weatherstripping has been removed, that it should fit. 

I am also looking into the silicone based weatherstripping and will likely order that or this Santoprene soon. (I also found some vinyl, but hope to avoid it). Thanks.


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## RustNeverSleeps (Sep 26, 2015)

Quick follow up. Based on mention from @carpdad in the thread "door kerf weatherstripping replacement not going well" I contacted Resource Conversation Technology about getting a silicone replacement. I liked the idea of using silicone after seeing how it performs in the kitchen. They were quite helpful and provided a few samples for test fitting before I committed to a full order. I really appreciated their customer service in trying to guide me towards the proper product and answering my questions. 

Photo of the samples below. Showing they have some variety available in the basic bulb shape and colors. Looks like all of them will fit into my existing window grooves, just a matter of getting the correct bulb diameter to match the top and bottom window sashes. I expect to place an order this week. (I should note that based on the test fitting, I expect that the Santoprene product mentioned above would work for my application as well).

The one of the left is the old weatherstripping. Besides the slight tinge of mold/mildew one can see the beige paint being picked up. I think that was the biggest problem, in that the weatherstripping had been removing the paint whenever any window was raised which would then allow moisture/mildew from the cool A/C leaking out underneath to compound the problem over a number of years.


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