Old bricks are porous and allow water to somewhat pass through.
Water is absorbed by the porous surface of old bricks, and in cold periods, expansion by freezing can cause them to crack.
Water is able to seep through pores and penetrate deeply into masonry.
The more it rains, the more water is able to permeate brickwork.
Because bricks and mortar are porous, they absorb water that can seep through the bricks and then run down the backside of the bricks.
If the water cannot drain, it could puddle inside the wall and potentially damage your home's structure.
A wall that has suffered a major wet spell takes a long time to dry out, rule of thumb is about one month for one inch of brick.
Always use a breathable sealant to treat brick surfaces.
Painting on bricks or using a non-breathable sealant can trap water under the surface and lead to more damage.
Also, make sure to tuck point on an as-needed basis.
According to the International Association of Certified Home Inspectors (IACHI), brick buildings are built to last 100 years or more.
Of course, that only happens with proper maintenance and normal wear and tear.
Routine inspections help identify sources of leaks, damaged mortar and cracks.
Bricks and mortar aren't 100% waterproof.
Even modern homes that are built with cavity walls and largely impermeable materials can still be affected by penetrating damp (water coming in from outside).
Damp and excess moisture within brick and stonework can lead to internal damage and the dreaded black mold.