I purchased a new home last year and all the windows installed are vinyl. My previous home built in 1999 had wooden windows. My question is are all the exterior windows needing to be caulked? I know with wooden windows that's a given. I had a lot of trouble with water damage on my old home and I don't really want to experience that again. Any advice would be greatly appreciated.


  • You should always caulk vinyl against any other non-vinyl material such as wood or brick which was not mentioned. Other thoughts?
    – Gary
    Commented Feb 24, 2017 at 0:53

5 Answers 5


You don't have to caulk something just because you normally caulk it. There is a reason why everything is done and learning this will save you time and money. Since you've had the home for a year already, I'd guess that you know if water leaks in or if you can feel drafts near them? If so, caulk it. If you have a reasonable doubt that they might not be installed correctly and could lead to water problems, go ahead and do it. Like you said, it'll save you from the experience down the road, but it might not be needed.


Vinyl windows, if installed correctly shouldn’t need to be caulked in too many places. Caulking on the interior is mainly for aesthetics. You will caulk where the drywall meets the frame or the casing meets the frame. You can use some painters caulk on the inside where the window meets the casing or the drywall. If it was installed correctly there shouldn’t be a draft coming from this area.


These windows require a lot more maintenance. All gaps should be re-caulked. If caulking after painting or if you have natural wood, you use a clear caulk. If caulking before painting you should use paintable caulk rated for exterior use.


Replacement windows are installed in existing wood frames. The windows come as a unit and should be caulked properly when installed. In situations with replacement windows, you have the area between the new window and the existing frame to keep caulk maintained as well as around any old trim.


  • I strongly disagree with caulk being used only "for aesthetics". Vinyl warps with temperature changes, like all materials, and creates gaps where air and moisture can leak. Caulking is used to seal and prevent open gaps, regardless of the materials.
    – Suncat2000
    Commented Jan 29, 2021 at 15:36

There is no difference between wood or vinyl. You insulate and caulk windows for insulation and to provide an airflow barrier. Almost all windows require caulking from the outside. If they weren't fitted and insulated well they may need caulk inside and out.

Unless the window was sealed with a good amount of spray foam after (and most of the time this will receded over time) they will have air gaps. You would logically caulk anywhere where air is coming in. An easy test is to take your garden variety leaf blow and blow at each window while someone inside checks for any airflow caused by blower.


Caulking will prevent insects from finding their way into your home through the window-siding seam. Water entry from leaky seam may also not be apparent for years....until you notice the wall bulging in and out during windy days, when lintels and braces have rotted from moisture rot.

$20 worth of caulk will save you a lot of trouble.


We use to caulk all sides of all windows. We even had details showing how to "caulk" and "back caulk" underlayment (building paper) onto the window or door frame. Now, two things have changed: 1) the use of peel-and-stick tape, and 2) understanding that moisture that gets "in" needs a way "out".

For new installations, peel-and-stick tape (you can find it in 3" or 4" widths) makes an easy way to make a positive seal against air AND moisture on all sides of the window. However, caulking is still required, but only on the jambs and sill. The industry's new position is that the moisture that gets behind the siding (we know all siding "leaks" that's why we install a moisture barrier) needs a "path" to escape. So now we spec the siding is to be installed on a moisture barrier with a small vertical groove that holds the siding out from the wall (about 1/16") and allows water to run down and out of the wall. This keeps the siding from rotting from the back side. The jambs and sill are caulked to seal up joints and keep the space as dry as possible. However, no caulking is applied at the head so any moisture accumulated above the window has a place to escape, (run out.)

To prevent air infiltration, we seal all edges of the moisture barrier, (I.e.: wall-to-Soffit, outlets, etc.)

For existing windows, we use the same method, except we will add a piece of head flashing and seal it to the moisture barrier with peel-and-stick tape. (Usually requires removing some siding...not easy.)

Remember, all caulking has a life expectancy. So, plan on some re-caulking in the future.


I recently replaced a kitchen wooden window with a new vinyl window. The old window had a j-channel installed and the j-channel was caulked to it, it also had a flashing with nail holes. The flashing had a flashing tape applied over it. The new vinyl window was ordered with the j-channel already on it and flashing predrilled for nails.

I took the interior trim and exterior siding off, removed the old window, slid in new one, nailed down, applied fresh flashing (picked up a short roll at Lowe’s for $10, Tite-Seal flashing), and put the siding back on. I filled the gaps with window/door expansion spray foam from the inside of the house. There was no need to caulk as any gaps would be sealed with the 4-inch wide asphalt tape.

This is a first time I replaced a window with a. Help of a friend and it took us about 3-3.5 hours of slowish and careful work, as the window was on the second level and required a use of long ladder - so we took it easy. Plus I expanded a framing a bit to make the window 3” taller - extra work.

If at all possible to easily put in a new construction window (it was in my case), I would do it this way.

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