Back deck paint peeling after one year?

Moisture could be the problem. If the deck is new pressure treated wood it does need to season due to the chemicals used to treat the wood. I have always used 6 months as a guideline and never had a problem. Primer is not necessary as deck paints are self priming (check the label) however the primer would not cause the peeling. Scrape down any loose paint. you may even want to use a pressure washer. If the deck is seasoned wood you only need to let it dry out for a few days prior to painting. If it is an older deck in rough shape this could also be the issue if the wood is deteriorated in which case the pressure washer would help remove some of the flaky wood off the surface. You can sand any rough edges but I would recommend 60-80 grit sand paper outside. An orbital sander would speed up the process. Good luck!

A wood sealing primer would have been the one to use. It penetrates the wood sealing it up and making it ready for paint. Also, as mentioned in other answer, if there is a moisture problem with the wood (from the inside) the primer and paint will not have adhered properly and it looks like you're in for a lot scraping!! Sorry!!

Sound like a moisture problem to me.Oil paint would not have been my choice but i:m not you.If it was a new deck with pressure treated wood it would have to been dried out completely before painting specially with oil paint.( about a year) Any moisture that is in there is coming out and making the paint peel.Now what to do?Scrap off the loose paint,spot prime, and re paint.When it:s good and dry that is.

check with the store that sold you the paint.

sounds like the deck had moisture problems. Is the paint pealing off the primer or all pealing. Make sure you know before you hit the paint store.

If all is lost, sand the area with 150 grit paper and repaint.

When wood is pressure-treated, it undergoes an intense process of infusing chemicals into the lumber. These chemicals prevent the wood from rotting and also keep harmful insects and fungi away from the wood. Since the chemicals have saturated the wood, traditional methods of painting simply do not work. You need to put a preservative on the wood and let it weather for 2 to 3 months. Most companies make both latex and oil-based products for pressure-treated wood. Be sure the paint you buy is rated for pressure treated wood. Stains often adhere to the wood better.

If the deck was new you need to wait a year before painting the deck to give it time to season.