Parging is a good choice when basement walls are flaking, crumbling, rough or stained and you want a sound, clean surface. It protects the wall face and makes the basement easier to live with. Parging is not a waterproofing system, though. If water is actively coming through the wall, that needs to be addressed first, or the new parging will fail.

Cost depends on the wall area, the condition of the surface and how much prep is needed before parging. Published cost guides put basement parging around $3 to $6 per square foot, or about $3,000 to $6,000 for a 1,000-square-foot job. Cleaning, patching cracks and priming can add $1 to $3 per square foot, depending on the wall. At BJK, projects start at $450, and we provide a project-specific price after a free on-site estimate.

Small, sound areas can be a DIY project for a handy homeowner, but parging is harder than it looks. The wall has to be cleaned, dampened and repaired first, the mix has to be right, and each coat needs to cure slowly to avoid cracking. On older stone and brick foundations, using a hard cement mix can trap moisture and damage the masonry. Poorly bonded parging often has to be removed and redone.

The most common parging problems are:

• Cracking: from water pressure, shrinkage or movement in the wall.
• Delamination: hollow spots where the parging has lost its bond.
• Flaking and crumbling: when moisture keeps moving through the wall.
• Efflorescence: white, chalky deposits left by water carrying salts to the surface.

Most of these trace back to moisture or poor surface preparation.

If installed correctly, basement parging can last 15 to 30 years. How long it lasts depends on the prep work, the mix and, most of all, moisture. Parging on a wall with ongoing water problems will fail much sooner than parging on a dry, sound wall.

It depends on the wall and the goal:

• Repointing: for stone and brick basement walls with sound masonry, repointing the joints is often the better repair.
• Waterproofing: for water coming through the wall, a waterproofing system addresses the cause, where parging only covers the surface.
• Coatings and limewash: for walls that only need a cosmetic refresh, breathable coatings or limewash can work on older masonry.

Only if the old parging is sound and well bonded. Loose, hollow or crumbling sections have to be removed first, since new parging will not hold on top of failing material. The surface is then cleaned and dampened, and a bonding agent is often used, before the new coat goes on.

Use a breathable, lime-based mix. Many older stone and brick foundations were built with soft lime mortar and need to let moisture pass through. A hard cement parge can trap that moisture against the masonry, which leads to flaking and deterioration behind the coat. The best approach is to remove failing material, repoint open joints, address any water problems and apply lime-based parging in thin coats.

Parging usually cracks for one of a few reasons:

• Water pressure or moisture moving through the wall behind it.
• Parging applied too thick in one coat, or allowed to dry too quickly.
• A poor bond to the wall underneath.
• Movement in the foundation.
• On older walls, a hard cement mix over soft masonry.

Finding the cause matters, because new parging over the same problem will crack again.