Higher property taxes. Major additions or updates, particularly in spaces such as kitchens and baths, can increase your home’s assessed value, and that can enlarge your tax bill. Assessors typically get copies of building permit applications, so they’ll know about your project and may determine that it warrants upgrading your home’s value.Hidden horrors. If demolition reveals a colony of creepy crawlies lurking beneath your drywall, you’ll have to call in the pest control folks to evict them before work can proceed. Insects and vermin are just one unpleasant surprise you might discover — you never truly know what’s going on behind the walls until a tear-out. Prepare for the possibility of mold, faulty wiring or plumbing, asbestos and other pricey pitfalls.
Offsite storage. You’ll need to stash your stuff somewhere while work is in progress. If you don’t have an attic, a basement or a willing friend with a large spare room, you may need to rent an offsite storage unit for the duration. Depending on size and other factors, these units can cost anywhere from $20 to a few hundred bucks a month.Building code quirks. Codes vary depending on where you live, but you may well face a list of requirements that must be satisfied in order for your permit to go through, particularly in an older home. For example, in obtaining estimates for a planned bathroom remodel, my husband and I learned that we’d need several new smoke detectors hardwired into the main electrical system, to the tune of several hundred dollars.
Utility bills. Whose electricity powers all those table saws, nail guns, paint sprayers and floor sanders? That’s right — yours. In addition, heavy traffic in and out of the house could pad your heating and cooling bills, especially in hot or cold weather.
Pet boarding. Got a hyperactive border collie or a cat who’s freaked out by strange noises? You may wish to send him or her to a kennel during the most intensive phase of construction, especially if you don’t have a fenced yard or other space where he or she can safely stay out of the way. Prepare to pay anywhere from $12 to $100 per day for the privilege. Dumpsters and portable toilets. Don’t be shocked to see these items in your contractor’s estimate. They help the crew maintain a clean job site and cause as little disruption to your home as possible. –From: http://www.houzz.com/ideabooks/3004921/list/8-remodeling-costs-that-might-surprise-you