Protecting Walls During Rain

Protecting walls during rain

Walls form an important part of the overall façade of your house. There is a tendency, however, for home owners to neglect walls when compared to other aspects of the home. This is in spite of the fact that walls form the primary protection of the home.   

Walls are exposed to the harshest vagaries of weather. With the possible exception of the roof, walls have the greatest exposure to the external environment. They are, however, required to retain their original look and feel even after facing adverse weather season after season. Whatever nature throws at your walls, they are supposed to come out unscathed. More often than not, the reality is far from this.

Some of the most notable effects that rain has on walls and by extension your home are:

  • Cracking of bricks. Cracking of walls.
  • Staining of external walls and interior finishes.
  • Corrosion of supports, anchors, exterior cladding etc.
  • Dampness, feeling of coldness and mustiness. 

Negligence, lack of maintenance, age, incorrect or poor installation as well as other factors add up to give room for rain to wreak havoc on your walls. For your walls to gain a measure of protection and ultimately achieve invincibility from rain, a number of protective measures have to be applied.

Before delving into some of the methods available it’s important to point out that the amount of rain has a significant impact on the performance of a wall. But the type of rain is just as important – is the rain you mostly experience driving, pouring, spitting, dirty, wind soaked, or, in these days of increased environmental degradation, acidic? Disparate answers will emerge. Each homeowner has a unique experience. With this in mind we look at some effective ways of protecting your walls against the rain, amounts and types factored in.


Periodic painting of walls using normal acrylic-based paints provides a beautiful decorative finish but little in way of protection from rain. Acrylic paints have a film thickness of 5,060 microns which just isn’t enough to prevent the development of cracks on your walls. Cracks lead to leakages which is a direct route for water to enter your walls.

The solution is waterproofing. Instead of using normal acrylic based paints, a high performance waterproof coating is recommended. Some elastomeric types have upwards of 110,500 microns film thickness that resists rain water. These coating are designed to repel water from your walls and are maintenance free. If your walls already have cracks a first step is to fill the crack using an acrylic-based crack filler.   

The state of your walls will determine the waterproofing treatment required. Old walls showing the adverse effects of penetrating damp that causes cracks, crumbling of mortar and plaster peels may require plastering before use of a coating. It’s always advisable to consult an expert for an assessment as each wall’s condition will be different. Keep in mind the amount of rainfall that the wall is exposed to also plays a role in the water proofing solution required.

Damp proofing

Dampness is one of the effects of rain. Rain isn’t the only cause of this. so before proceeding with damp proofing your walls it’s important to get to the bottom of the problem.  Broadly, dampness is due to rising damp, penetrating damp or condensation. Rain-related causes fall under penetrating dampness. Driving rain, more than any other type, is noted to cause this.

A damp-proofing method for internal walls involves use of damp proof membranes made of high density Polyethylene and Polypropylene. The application of the membrane is important to the overall effectiveness of the method. A properly applied membrane allows unrestricted evaporation of moisture from the wall. A suitable wall finish can then be applied to the wall.

Ventilated façade structures

Building designers worldwide have adopted ventilated façades to protect building exteriors. The façade, sometimes referred to as a rain screen or double skin, consists of a support structure and some external cladding. An air cavity separates the two, while anchor elements are used for joining the support and external cladding. A waterproof membrane is additionally incorporated to the external cladding for added water repulsion. The external cladding can be made from a variety of materials: aluminium, timber, cement composites, tiles such a terracotta, and even photovoltaic.

The ventilated façade has found great appeal and application in retrofitting old building. It’s also used in areas prone to wind driven rain.

Walls will always be exposed to rain. But you need not suffer the negative effects of this exposure. With the right maintenance and application of some of the techniques discussed your walls will stand the test of rain, retaining their original sheen and without losing any of their properties.