Urinating in the house

Question
Hi there Dr Fry,

I have recently adopted a boxer/bullmastiff cross bitch from an animal rescue shelter.  Meg has been sterilized and we have another sterilized spaniel bitch.

Meg is between 12 and 18 months old and does seem to have had a horrible life up until now, she's not aggressive but she is very playful and rough but she's extremely well behaved and resposive and does what she's told.  Her size and looks obviously led some deviant to think she'd be good at fighting as she has scars and signs that she's been in a number of fights all over body.  She even has a long bald scarred area along her shoulder where someone poured boiling oil on her (according to the lady at the animal rescue) Having discovered that she wasn't cut out for fighting whoever had her threw her out of a moving car, the person driving behind the car from which she was thrown brought her to the pound and we adopted her about 3 months ago.

My problem (other than the fact that people can be so cruel which I doubt you can help me with) is that she's taken to urinating and defecating in the middle of our lounge floor (always in the same area).  All the doors in the house are open when she does this so it isn't a case of not being able to get outside and she's well aware of the fact that she'd doing something wrong because she sits and waits till no one is around before she does it and then she runs away and hides after she's done it.  This morning after about the 15th or 16th time this has happened I caught her in the act and she ran outside, I tried to bring her back into the lounge so that I could make her aware of what I was cross with her about and she began screaming and yelping so loudly that the neighbour came to see what was going on.  I hadn't in any way hurt her or raised my hand as though to hit her I'd just tried to bring her back into the lounge.

How can I stop her from going to the toilet in my lounge without traumatising an obviously already traumitized dog?  In all other respects she's very well adjusted, a bit subservient to other dogs but she seems like a very happy dog.  

Answer
You need to crate her when you are not home or sleeping at night and take her outside on a leash every 1-2 hours until she is house-trained.  PRAISE HER and REWARD her with a special treat when she goes outside to the bathroom.  You can not expect her to know to go outside on her own to do her business.  You should not punish if she has an accident because this will only make her more scared and more likely to go in the house.  If she is running around the house and you see her squat, tell her NO firmly and take her outside immediately.  I would put baby gates at the lounge and deny her access at this point.  Also, make sure you are feeding her on a schedule and not leaving the food dishes out all day.  And you may want to limit water at night.

Also, it may serve you well to do some internet research on house training and crate training.