My Sib Summit is 1 yr and 5 months.. He is potty trained and knows he needs to go outside. He can hold it for long periods and not have accidents.

It took him till about 7 months to be potty trained, i'm not sure if this was just due to his stubbornness or if i was doing something wrong in training. Every now and then though he has an accident in the house. He knows its wrong and bad because when we come home he hides. When we tell him bad dog he curls his ears back and slinks away. Its hard to punish for the action when he already knows its bad. We put him on time out every time but he still does it.

It used to be a few times a week but now its maybe once a month which is a huge improvement. I'm just wondering how to stop him from doing it completely. (crating him is not an option... been there done that)

We make sure he goes out before we leave the house, we physically watch him do his business and then he comes back in and we leave.

a part of me feels like he is doing it because he is mad at us for leaving??

one time i had him outside and he then came in and i went out to the garage for 10 min because we had friends over.. came inside and he pee'd in the middle of the kitchen... after just being outside 10 minutes before. I feel like it was out of spite.. but i know not every case is like this.

gotta love teenagers.. any tips to help me save my floors??  

He's not fully potty trained if he's still going inside and probably the best course of action is to go back to step one and treat him like an untrained puppy.  I have a 13 month old pup that is almost there, he has maybe 1 accident a month in the house so I cannot consider him fully house trained, but I feel like we are almost there. It's been 6 weeks since his last accident so I'm hopeful!  The crate has really been extremely helpful with housetraining though. And believe me it was quite a struggle crate training this one but we got through it. Why is it that you can't, or won't, utilize a crate?

Edited to add: Since you won't use a crate, do you at least restrict his freedom in the house to smaller areas to discourage doing his business where he can get away from it?

We tried crate training from day 1.. It was a Major struggle but we kept at it. After 4 months of having to clean out his crate everyday i gave up.

He would sleep in his crate fine as long as we were home, as soon as we leave the house it was chaos. He would have explosive diarrhea almost instantly. He would pee and poop and then walk and lay in it and spread it everywhere. I cleaned his crate everyday for 4 months when finally i couldn't do it anymore.
We had him vet checked in case it was a medical problem but it wasn't, we bought a different crate thinking maybe he just didn't like that one, tried to positively reinforce that crate for him, gave him treats, fed him in there, tried the thundershirt. but nothing worked. As soon as we leave the house it was the same thing every time.
We then took a break from the crate and decided to see if he was trust worthy left alone, and he was. Never damage anything, and he was not having very many accidents either. After a few months we tried to crate train again from step 1 but again a repeat of the first time.

I have accepted the fact that he is bat shit crazy and cant be confined haha.

We dont give him full access to the house, he is baby gated from certain areas.

i guess im in the same position as you.. up until last night it was almost 7 weeks with no accidents. I feel like he is potty trained i guess because he knows right from wrong, but chooses to keep doing it..

Again, if he still goes in the house for reasons other than true accidents (like diarrhea which he just can't help) then he's not fully house trained. Also, dogs don't do things like pee or poop in the house out of spite, that is a human emotion that dogs aren't capable of despite how it feels to us.

When he does go in the house, is it usually when you're not home or when you're home? Or is it about equal? If it's generally happening when you're home, you might consider trying the tether method. Where he is tethered to you at all times, thus never giving him an opportunity to sneak off and potty privately in the house. I used the tether method with my late, Faith, who was a challenge to house train when we adopted her shortly before her 4th birthday. It worked wonders with her and I used it again to some extent when we got Prince in June at 9 months old.

He never does it when we are home.

Except for the one time i went out to the garage for 10 minutes and came back to him having pee'd on the floor after being outside 10 minutes before that.. This is the only time i feel like it was out of spite.
He was outside for almost an hour, came inside, i went to the garage for 10 min and came back. Maybe he thought i had left the house for longer then expected i dont know.

I do realize that spite is a human emotion but its very easy to believe that they can feel this way because they do display very human emotions often. Especially huskies, they have so much character and facial expressions its hard to believe i own a dog sometimes haha

So my next question would be how long is he left home alone when he goes in the house? Could it be that he just couldn't hold it until you returned? I know sometimes even my potty trained adults might have an occasional accident if they drink too much before I have to leave or if I don't take them out soon enough after they've had a big drink. While I no longer use the tether method with Prince, I do make sure he is within sight at all times to prevent an accident. He's crated when I'm not home so that's not an issue for me.

The longest he is left home is 8 hours. I work mon to fri

This used to be when he would have accidents but he can hold it for longer then 8 hours now so its not an issue while im at work anymore..

The past 5-6 months it usually happens in the evenings while we are out somewhere. No longer then 4 hours.
I know a couple times it was because he ate and went out but didnt do anything outside and we had to go somewhere. This is not blamed on him, that is our problem completely.

Its hard to say exactly how long we were gone each time because it only happens once a month sometimes less..