By Gene and Katie Hamilton

If you have a brick house or fireplace with blotchy white spots, it's probably efflorescence, a condition that develops when moisture from within the bricks rises to the surface and evaporates. The residue is a deposit of mineral salts that looks like a white powdery substance. Since the cause of the efflorescence is excessive moisture behind the brick, first find its source and correct the problem. It might be a leaky gutter or loose downspout that allows rain to run down the brick. Or it may be as simple as adding caulk around doors and windows to prevent the moisture.

A house cleaning service will charge $104 to remove efflorescence from a150-square-foot area, which includes the labor and material. You can remove the substance for $15, the cost of a clear water sealer, and save 85 percent. You need a stiff bristle wire brush and a garden hose or power washer to scrub the surface; then apply a clear water sealer to protect the bricks. And take precautions to protect the plantings around it by covering them with a drop cloth.

If the efflorescence is located on bricks on the second story of your house, we think it's definitely a job for a service who has a crew with ladders and the experience to work on them. If the white blotches are only on the first floor and easy to reach, it's a doable job for a homeowner.

The Masonry Institute explains The Cause and Control of Efflorescence.

Wrapping up, given the average cost to remove brick efflorescence you can compare the price of a contractor’s bid with doing it yourself. For a local cost input your ZIP Code.

Improvement and Repair Cost Updated 2019

The cost and time data is generated by averaging labor and material data from annually updated cost books used by contractors and refined by the authors' experience remodeling 13 houses. They are authors of 20 home improvement books and Do It Yourself or Not, a weekly column syndicated by Tribune Content Agency. The national cost can be adjusted by ZIP Code.