I suspect the deck was either painted or that it received multiple coats of stain.
Why would stain peel from wood siding.
If too much stain is applied the excess material will linger slightly above the surface and prevent moisture from rain and dew from leaving the wood.
You can clearly see the low quality paint sold as stain peeling.
Another insidious cause of solid stain failure on cedar has to do with dead wood fiber on the face of the siding.
Has encountered a troubling issue with cedar siding.
Also it operates in a similar manner to paint and will peel if not properly applied.
Although they are designed to penetrate multiple applications or over application in a relatively short period of time without the benefit of natural weathering can cause a film to form on the surface.
Peeling paint or stain that comes off in sheets all the way down to bare wood on the sunniest side of the house.
No stain or paint can adhere to dead wood fiber leading to major coating failure.
This is a telling sign of the problem.
Paint peeling on a wall next to a bathroom means condensation on the back of siding is being drawn through the wood when sunshine warms the wall.
Install an exhaust fan vented to the outside.
Sometimes moisture can and will.
If there is too much stain it restricts the moisture from evaporating away so peeling can occur.
When the peeling stain is scraped off dead wood fiber often stays stuck to the back of the flake.
They just weather away.
Wood can only absorb so much stain.
Cabot semi solid stains and cabot decking stains can flake and peel from wood siding or deck structures if these products are over applied.
In particular the bad prep can be from a dirty poorly prepared surface or because moisture migrating through the wood from behind the siding.
Stain can peel off in sheets because of many reasons including poor adhesion caused by slapdash prep choosing the wrong paint.
If this moisture can t evaporate it will remain on the surface and begin peeling away the stain.
It s peeling in places and needs to be recoated.
Years ago the wood siding on the clubhouse was treated with what i believe to be an acrylic solid stain.
If window trim alone is peeling pry off trim boards and plug gaps around the frame with a low expansion foam sealant.
This type of stain is ideal if you re living in a very sunny region and are looking to block the sun without changing the colour or appearance of your exterior siding.
Most stains absorb into the wood surface so they don t form a film that could peel off.