This from installation instructions.
Caulk wood plank siding before painting.
Caulk should dry before painting over it otherwise it can cause new paint to crack and warp.
However if you re working on certain surfaces the caulk will not stick without a primer base coat.
Some specialty caulks may need a primer before paint is applied but most caulking is paintable.
The different kinds of caulking for your home.
There are several different types of caulking on the market.
Sometimes the old caulk in the siding joint is cracked and you need to cut the old caulk out with a razor knife.
Similar to paint previous coats of.
Basically any crack on the exterior of the house should be filled.
Joe i think your image is specifically for colorplus where they don t recommend caulking.
For regular hardiplank lap siding the kind you paint after installation caulking at butt joints is optional.
This allows for the caulk to get in and fill the gap correctly.
For caulk that will be painted over a latex caulk should be used.
Unfortunately it will not stick well to stained surfaces.
When exterior caulking becomes defective it allows moisture and rain to seep between siding boards behind the trim and eventually reach the drywall of the interior.
Under normal circumstances you can apply caulk before priming.
Old caulking that has failed and allowed water to migrate behind the siding can cause wood rot decay and if left undetected mold will most likely grow in your walls.
Caulk and seal all cracks in the siding as well as any open seams joints or gaps with a quality acrylic or siliconized acrylic caulk.
This can cost hundreds to thousands of dollars to eradicate.
Unlike similar sounding silicone caulks siliconized acrylic caulks can be painted so they enhance the finished appearance of the paint job.
For best results use caulks that comply with either astm.
A high quality paintable caulk is recommended.
This is the beginning of rotting wood water stains mold and mildew and possible flooring damage.
Scrape away any peeling paint adjacent to the caulked areas.
The nails holding up the siding should not be caulked.
If the siding joint is so tight that the caulk only bridges the gap it may split again.
Let the caulk cure for a few days before power washing the exterior.
Don t caulk the horizontal joints on siding where the siding courses overlap.
A diyer or a novice painter might attempt to achieve a cleaner look by caulking the siding nails but the nail is guaranteed to push the caulking material out within a few months.