The basic answer is that wood warps because of uneven drying rates within the wood fibers.
Causes warped wood siding.
An improper maintenance schedule could be to blame for warped wood siding.
In 2008 new darker colors were introduced to the vinyl world and now two to three years laters these dark siding colors are buckling and warping due to heat attraction that they draw from direct sunlight.
They range from woodpeckers searching for a meal to bugs and carpenter bees looking for refuge and sustenance.
Sometimes the actions of a homeowner can be the problem.
Sometimes holes in the wood siding are the reason for the siding being warped.
The ones exposed to more air and heat near the outsides of the pile had dried in unexpected ways.
If the siding was pushed upwards too tightly clamping very tight on the connecting lip of each siding segment below it might have encouraged stretching then warping and loosening due to subsequent heating.
Vinyl meanwhile is far more durable.
Let me provide you with some.
This is just something you cannot let go for too long otherwise it ends up costing you more in the long run.
When was the last time you had the house cleaned stained.
Termites will tunnel their way through wood as will powder post beetles severely limiting the protection your siding will offer.
Poor drainage can also cause problems and even sprinklers that constantly hit the side of a house can cause wood to become warped.
Additional causes for warped siding include structural issues such as missing studs improper nail placement or using the wrong nails during installation.
While less common termite or pest issues can also be the cause of warped siding if they begin to eat away at the structure of the house.
If this is the case you can use stainable wood putty to fix these holes.
Some debris may have gathered in the holes.
Wood can only withstand so much of a beating from a combination of sun wind rain and snow before it starts to fall apart.
Moisture causes wood to expand.
Wood siding is particularly vulnerable to pests.
As my boards had sat there throughout the summer.
The reason siding becomes warped is because the ends of the wood boards were placed too close to each other when they were installed.
First clean out the holes carefully.
Water damage can cause warped siding water exposure is a major issue with wood siding which is why so many homeowners prefer vinyl siding over wood siding.
Using a bristle brush you should thoroughly clean out the hole.
Not all siding buckling and warping is from poor installation.