G'day folks!

I brewed an American Amber Ale approximately two weeks ago. I used a recipe from Brewing Classic Styles. die OG was 13°P (1.053). I took a reading 10 days later and the FG was 6°P (1.024), which was unacceptable
But I nevertheless waited another couple of days and took a reading this morning and the FG stays at 1.024. The sample I tasted wasn't overly sweet at all but I am still worried about my beer, therefore I placed the fermentation vessel into a warmer (22°C) room.

I mashed at 68°C and did a mashout. 11gr of rehydrated Safale US-05 were pitched.

What should I do if the fermentation ceased completely?

Perhaps you could rouse the yeast with a gentle swirl of the fermentor, just enough to bring them back into suspension. Then, I would give them another couple of days to see if they want anymore to eat.

Another possibility is that, although you followed the instructions to the letter, the mash temperature may have been a bit high. That would produce a wort with more body and less fermentable sugars. If this were the case, I would just package and enjoy, and remember the experience for the next time and reduce your mash temperature to around 65C. This will allow the enzymes to nibble away and produce a more fermentable wort.

hope this helps,
Alan

Just swirled the yeast back into suspension

I was anxious about the mash temperature as well, but nevertheless I'd thought that Jamil knows best

you gave it the swirl when you moved it to a warmer room. if it's still stuck, make a starter and pitch it when it's at high krausen. are you using a refractometer to check your OG? if so, download the spreadsheet on using a refractometer from the tutorial section at morebeer.com. it reads higher because you are dealing with an alcohol based solution, not a water based solution. good luck, Drew

I am using a regular hydrometer, but thanks for the advice!

Make sure your hydrometer is reading accurately if you haven't already calibrated. Should read 1.000 in water.