How to tell if your house needs tuckpointing

Start with the key test

Pick a spot at eye level and drag a key or a flat screwdriver along a mortar joint. Sound mortar is hard and barely scratches. If it crumbles, turns to sand or comes out in chunks, that joint has worn out.

Look at how deep the joints are

Good joints sit close to the face of the brick. A common rule of thumb is that once mortar has worn back about 1/4 inch or more, it's time to repoint. Deep, dark gaps between bricks are the clearest sign.

Check the spots that wear out first

• Chimneys, which take weather on every side
• Parapet walls and the tops of walls
• Walls under leaky gutters or next to downspouts
• The side of the house that takes the most wind and rain
• Front steps, stoops and porch walls

Signs inside the house

Worn joints let water through the wall. Look for damp spots, peeling paint or bubbling plaster on outside walls, water stains around windows, and a musty smell in the basement after it rains.

Other signs it's past due

• Sand or grit collecting on window sills and along the foundation
• Loose bricks, especially around windows and at the top of walls
• Cracks running through the joints in a stair-step pattern
• White staining on the brick
• Brick faces flaking or popping off

What not to do

Don't caulk over the joints or smear new mortar over the old. It traps water and fails quickly. Avoid very hard mortar on older, softer brick, too. Mortar should be softer than the brick so the joints take the wear instead of the bricks.

When to call

If you're finding more than a few soft joints, it's worth having someone look. Around Chicago, tuckpointing is usually done April through November, when it stays above about 40°F while the mortar cures. Text us a few photos and we'll tell you what we see.

More homeowner guides

• Chimney crown vs. chimney cap: what's the difference?
• Why brick cracks above windows
• White stuff on your brick: what efflorescence means