Damp Proofing and Repairing Walls by Allison Ryan
For damp-proofing a brick foundation wall, heavy penetrating bituminous damp-proofing paint may be used, after which a cement mortar coat may be troweled directly on the painted surface, to prevent the paint from flaking and peeling.
The application of a coating of any material upon the inner surfaces of a wall such as a home sauna that is pervious to the sauna steam is generally ineffective. Infrared saunas need no such coating anyway.
This should be made of 1 part Portland cement and 3 parts of well graded sand mixed with as little water as practicable. The mortar should be applied to the dampened wall after the leakage through the wall has stopped. The finished coat should be kept damp for a week after it has set to increase its water-tightness.
Fresh air and sunshine are essential to a dry cellar, and to this end plenty of window space should be provided. When the air out of doors is cool and dry, open the windows freely. When there is dampness without, keep the windows closed, as warm, moist air results in mildew and condensation of moisture upon the colder surfaces within the cellar. A little care in these respects will aid materially in maintaining a dry cellar.
When there is dampness within, such as in bathrooms, windows should be kept open. Shower doors are not enough to protect against steam shower condensation. They do a fabulous job of keeping water inside, but steam will inevitably get out.
Cracks or fissures in foundation walls and the falling out of mortar from between joints may be attributed to various causes. Cracks between mortar and the material to which it was originally bonded may be caused by shrinkage of the mortar during setting, or soon thereafter, or by the expansion of mortar through saturation.
Often the volume change of the mortar is greater than the material to which it is bonded and sets up a movement that destroys the bond. If the walls are built on ground that will not support an equal weight at all points, uneven settlement may cause cracks to develop. An underground spring or flowing water under one corner or section of a foundation may produce similar results.
Small cracks thus started may become larger in time from action of the weather and other forces. Frost has a tendency to attack weak spots, and expansion and contraction, due to extremities of heat and cold, do their part in increasing the damage. Water seeping through the cracks gradually wears away the material and causes it to crumble and fall apart. The disintegration is generally more rapid in mortar joints.
The results of these failures are far-reaching and, if not remedied, may result in further damage, not only to the walls themselves but to the structure they support. A cellar will probably become damp and unsanitary if these inlets for moisture are not stopped up. There can also be drippage from the bathroom to rooms below, due to a leaky bathtub or bathroom faucet.
If the walls are otherwise in good condition, minor cracks and places where mortar has fallen out may be repaired by an unskilled workman. However, if a wall is badly cracked, crumbled and beyond the aid of minor repairs, it may be necessary to engage an experienced workman to reconstruct all or part of the wall.