It needs to move and breathe.
Caulking cedar lap siding.
It is generally not a good idea to use caulking on wood siding.
I m not a painter but i do install cedar siding and i always caulk all the joints.
Whether you are repainting replacing a window or replacing the siding on your house the caulking around the window trim is a very important element.
The corner boards and the ends of the siding are nailed to the corner studs which anchors the wood for a maintenance free joint.
Width is a matter of taste and proper proportion.
Caulk by its adhesive nature will try to limit this movement leading to widespread failure and cracking in the caulk over time.
If i am installing a prefinished product which i do mostly i use a color osi match caulk.
When deciding how to use caulk on your siding however it is generally more important to consider where you should not use it.
Corner boards are applied to the sheathing with siding fitting tightly against the narrow edge of the boards allowing for expansion and an adequate caulking bead.
How to caulk the window trim on lap siding.
Think of a wood home as a living thing.
The siding expands and contracts with temperature and humidity.
Generally we do not recommend caulking butt joints on cedar siding.
Natural siding boards are designed to expand and contract with the elements and we do not want any adhesive to prevent their natural movement.
When you try to restrict either it is at your peril.