One of the most common stages in a major remodel is cutting into a wall to create a doorway. Before doing so, however, you will need to determine what obstacles there may be in the wall. Following are some things to look for:

Your first clue is what rooms are on either side of the wall. Kitchens and baths, in particular, suggest plumbing and electrical embedded in the wall.

Go outside your house and look for anything projecting through the roof in the area above the wall, such as pipes. If you see pipes, there are likely drainpipes in the wall, and also possibly water pipes.

Go back inside and look at the rooms above and below the wall. If a room above has a radiator that sits against the wall extension, there is likely a hot water or steam pipe in the wall below. If a room below has a hot-air register in the wall extension, the wall may contain a heating duct. Remove the grille on the register and, with a flashlight in hand, reach in to see where the duct goes.

In all rooms on either side of the wall, and above and below, take note of where electrical receptacles and switches, plus light fixtures are located. This will give you a clue about where electrical wiring may run.

Finally, if you can access your attic, use a flashlight to locte the top plate of the wall. Note any wires, pipes or ducts protruding through the top plate. If you can also access your basement or crawlspace, do the same investigation there.