here is the reply i got from ea customer support about the multi tile addon issue.
"Greetings,
Thank you for contacting Ultima Online support.
Visiting your house in-game I have found a few matters that can be problematic with the design of the house itself. Walls are missing or not used at all, characters can walk off the house harming themselves and the likes.
Game Masters cannot assist you in the re-design of your home, however I would strongly suggest to try different house design approaches. I would also like to invite you to read our Knowledge Base on game matters of general game information:
http://support.ea.com/cgi-bin/ea.cfg/php/enduser/std_adp.php?p_faqid=5904 would be a good place for you to start;
http://support.ea.com/cgi-bin/ea.cfg/php/enduser/std_adp.php?p_faqid=1929 can also give tips on what to look out for.
Even if this design worked for you in the past, I can sadly not suggest anything else with the current houses design.
I am sorry for any inconvenience this may cause you.
Regards,
EA Rep Glathin
Player Relations
Electronic Arts"
basically the response was build walls or build a bar.
this answer did not address my issue with not being able to place the multi tile addons on the east edge. yes on 1st and 2nd floor and the top i left out the walls on the east side. i created one big arch on the east side of my house since you lose that space for decorating if you use walls all the way across. i used the large stone tables, large forge, water trough, and aquarium to prevent me or anyone else from falling off my house. the tables fit just fine on the south side that has no walls but still wont let me place on the east side. thanks to all who are trying to help get some sort of response as to why this was changed after so many years of customizing houses and being able to use the east edge of the house. i too would like to use all tiles for displaying my goods/rares.