How to Repoint Brick Mortar Joints

Repointing involves removing deteriorated mortar from brick joints and replacing it with fresh mortar to restore structural integrity and weatherproofing.

Spot the Damage First. Examine your brick walls for cracked, crumbling, or missing mortar joints. Look for gaps where mortar has fallen out completely, areas where mortar is soft enough to scrape with a fingernail, or joints that appear powdery. Focus on areas that get the most weather exposure first, as these deteriorate fastest.
Clear Out the Weak Joints. Use a mortar rake or cold chisel to carefully remove deteriorated mortar to a depth of about 1 inch. Work slowly to avoid damaging the bricks. A grinder with a diamond blade works for stubborn mortar, but use it sparingly as it can chip bricks. Clean out all loose debris with a wire brush and flush the joints with water.
Get Your Mix Right. Match your existing mortar type and color as closely as possible. Most residential brick uses Type N mortar made from 1 part portland cement, 1 part lime, and 6 parts sand. Mix small batches that you can use within 30 minutes. The consistency should be similar to thick peanut butter.
Pack It In Tight. Use a pointing trowel to pack mortar firmly into the cleaned joints. Start with the vertical joints, then do the horizontal ones. Press mortar in deeply, slightly overfilling the joint. Work in sections of about 3 feet at a time to maintain a consistent appearance.
Shape the Profile Now. Once the mortar is thumb-print hard (usually 30-60 minutes), use a jointing tool or the back of a spoon to shape the mortar profile to match existing joints. Most residential brick uses a concave profile that sheds water well. Remove excess mortar with the edge of your trowel.
Baby Your Mortar. Brush away loose mortar crumbs with a soft brush. Keep the new mortar damp for 72 hours by misting it lightly with water twice daily. Avoid working in direct sunlight or freezing temperatures. The mortar will reach full strength in about 28 days.