What to Caulk & What NOT to Caulk on the Exterior of Your Home

Caulking is one of those tools of the trades that when used properly can be a huge help on the outside of your home.

On the same token, it can cause disastrous results if used improperly…

Assuming you are using a good quality caulk (do NOT skimp out here!), and it is used in the right place (with the correct caulk product), the caulking should help guard against moisture sneaking into inopportune areas.

A great place to use caulk is on the trim joints of your home, this includes areas where siding meets the trim joints as well as areas where trim joints come together.

Caulking should be applied after the rest of your surface preparation is done (including primer) and should be applied in a smooth, even fashion.

I am a bit ‘old-school’ and when I caulk, I like to use my bare finger with the assistance of a clean rag to help smooth out the caulk in joints after it is applied.

I suppose the more proper method is to use a wet rag – vs. your finger – when smoothing out your caulk-lines (though this just does not seem to be as fun!).

It is important to note that you should keep in mind how wide a joint you are working to caulk is when cutting the tube of caulk.

You do not want too thin of an opening for a joint that is a bit wider, nor do you want too wide of an opening if your joints were fairly tight to begin with and simply needed some reenforcing of the seams.

As valuable as caulk can be in helping to close up joints and prevent moisture from sneaking in where it is not supposed to be, it can actually lead to some pretty horrible things when used in incorrect areas.

How do I know?


Because my super-genius guidance when it comes to where to use caulk has led to doozies which have cost thousands of dollars to correct (I look at situations like this as “tuition”!).

There is the time (going back a good 30 years) when I had our guys caulk every single nail hole on a home where solid stain was going on the front of it.

After doing this and applying the finish coat, every nail hole on the home bled through a darker version of the siding color and we had to painfully dig out every bit of caulk from all those nail holes and properly putty them as they should have been done in the first place.

Then there was the time that I had our guys caulk the butt-ends of the clapboard all around our Client’s home because cosmetically it made things look so nice…that is of course until the entire coating structure on the outside of the home peeled everywhere because we sealed up the house so tight, that it could not breath and the built up pressure caused the paint to pop on the siding all around the house.

Again, painstakingly, we had to have our guys take every bit of caulk out from the butts of those clapboards and aggressively treat the exterior of the home in order to undo our (unintended) wrongdoings.

There are numerous other examples.

Really paying attention to areas that should absolutely have caulk, however, vs. those that should NOT have it (…and learning from the mistakes of others…) can help ensure that this simple product known as ‘caulk’ is able to have its benefits maximized while avoiding what could be a costly mistake if not put in its proper place (even if it may look ‘nicer’ at the time!).

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