Brick is a highly durable and attractive building material and there are many fine examples of brick buildings and structures that are centuries old. However like all building materials, if no or inappropriate maintenance is carried out, then problems can occur.
In my opinion these are the five most common causes of avoidable damage to brickwork:
- Repeated saturation
- Vegetation growth
- Corrosion of embedded metalwork
- Inappropriate cleaning
- inappropriate repairs/maintenance
This can be due to blocked or damaged gutters and downpipes, running overflow pipes or poor design details.This repeated saturation can cause internal dampness, the corrosion of embedded metalwork, the rotting of built in timbers, the growth of plants including mosses and liverworts, the deterioration of mortar joints, the spalling of brick faces due to salt migration and recrystallisation behind the brick face, efflorescence, frost damage due to repeated freeze thaw cycles and unsightly staining of the brickwork.
Not all plants that grow on or against brickwork cause serious damage. However, trees and woody shrubs that become established in walls are always harmful as their root systems invade cracks or crevasses in the walling and grow in thickness. The expansion forces caused by the thickening roots can eventually force the brickwork apart and displace it. This can ultimately lead to full or partial collapse of walls and chimney stacks.
The trees and shrubs that most commonly invade walls are ash, sycamore, hawthorn, yew and elder. A major problem can be caused by buddleja which is a non native, invasive plant which can quickly become established and overwhelm brickwork especially chimney stacks and boundary walls.
Climbing plants such as the common english ivy (according to new research) are generally not, if at all as damaging as previously thought and in some instances may even be beneficial by protecting the walling from rain and other damage. However, if they are not properly managed they can block or dislodge rainwater goods and may conceal other building defects. Vast growths of ivy on slender walls or chimney stacks can also cause unsafe loading (especially in windy weather where it can act as a sail) and in severe instances this wind loading may even cause collapse.
Ivy which is rooted in the wall and not the ground is always damaging. This rooting in the wall can be caused if the ivy is neglected or the main stem at the base is cut (usually to kill the plant). When this happens damaging roots may be produced, usually at leaf nodes which can then invade the walling.
In part two I will discuss the damage caused by corrosion of embedded metalwork, inappropriate cleaning and inappropriate repairs/maintenance.