cat refusing to use litter box

Question
We have a 13 year old cat who has been litter trained since day 1. We do occasionally let him outside for short periods of time, especially when it is nice out.  In the last month, he has totally refused to use the litter box.  He is very brazen and will do his "job" right in front of us.  I have scrubbed his box, put new litter in it and he still refuses to use it.  

We also have a dog (for the last 7 years).  We have a sceened in patio with a doggie door to an enclosed area where he goes out to do his duty.  That is also where the cat goes when outside.  The cat will go into this area and go but not when it is raining. My husband and I both work and I don't want to leave him outside all day or at night.  I woke up to a big pile this morning, even though I put his litter box in the room where i have closed the door and left him in the last two nights to keep him from going everywhere in the house.  

Please help me and my kitty.  I am at my wit's end

Answer
Hi
sounds to me like he is marking his territory. this may be because something has happened outside which has made him feel a little fearful. this is not uncommon behaviour and can be helped with some litter retraining which also helps to build the cats confidence again.

Please read my page about this issue it also contains the information about the retraining using the confinement method.

/cat-poo.html

best wishes kate