Take if from someone who has "done battle" with the City of San Jose in the past...you absolutely, positively need a permit to do almost anything in your home. Examples of changes that would require permits are:
1. Any major work visible from the exterior of the property
2. Changes the liveable square footage in your home (for example, adding more space to the inside or converting a garage)
3. Involves plumbing, electrical or heating systems in your home
4. Involves replacing any exterior "covering" to your home (stucco, roof, windows)
5. Changes the "footprint" of the home
6. Adding an "out building" or permanent storage shed that is electrified or can be used as living spaces
Of all the cities in the Santa Clara County, architects, structural engineers and building conformance engineers will tell you that San Jose is the most vigilant in "red tagging" changes, and the most difficult in getting repairs and proposals approved. The planners within the city are very particular about the manner in which the changes are presented, completed, and inspected. So before you attempt to even put forth a permit application with the City, work with a contractor or architect with a proven "track record" of working successfully with the City of San Jose. They will know not only WHO to talk to and WHO to give the request to, but will also know exactly HOW to present your application in a manner that will most likely get approval from the City's planning department.
Most importantly, do not disregard the importance of a permit, because the City's inspectors have "zero" tolerance for changes made without approval. In fact, I know of one homeowner who purchased a lovely home in San Jose only to find out 30 days after her close of escrow that 1/2 of the property consisted of an unpermitted extension and she was given the order to tear it all down and restore the home to 1/2 of its present size. By the way, she did NOT win her case with the City, and did have to tear out the extension.
So get a great contractor first (one who has worked with the City and knows people within the Planning Department with which to work) and then submit your plans for an extension. Do NOT try to add the extension without the permit--you will rue the day you did.
If permits are not pulled, at the very least a lender will require inspections and verification that the work was done to code and in a "workmanship" (professional) manner. At the worse case, if you have violated or exceeded San Jose building codes, the City can require you to remove the addition and return the home to original condition.
Not getting a permit is NEVER a good idea.
All my best,
"We Listen. We Care. We Deliver."
It is always in the best interests of the homeowner, the city wants to make sure you do the job correctly. As a benefit to you, when you go to re-sell the house, you will have all the paper work and provide it to the new owner that everything is "up to 2013 building codes" .
If you need any help with the design process, the permitting process, or the construction of your new addition, please feel free to contact me.
Timber Creek Construction
Realty World/Blue Property Group
Karen Xu, Intero Los Gatos.