How does water drainage affect your home's foundation?
May 15, 2015
Water drainage is the single most important aspect of building a house's foundation. It can affect the foundation if the drainage is poor. Water can be very destructive to foundations, basements and crawlspaces and will be very costly to repair.
By Umar Nsubuga
Water drainage is the single most important aspect of building a house's foundation. It can affect the foundation if the drainage is poor. Water can be very destructive to foundations, basements and crawlspaces and will be very costly to repair.
Abdu-Wahab Nyanzi, an architect says drainage is one of the things we deal with regularly that it would not seem like a problem. But it is, and a lot of houses have deteriorated due to bad drainages.
“Drainage for foundations in particular should not present as a big challenge. But for the fact that the house is built once, ensure that you have a good architect. If water stays undetected and does not drain properly, then the water will soak into soil. This causes the area where the standing water is to swell up more than the adjacent swells”, says Nyanzi
When looking to build a foundation, the first thing to do is make sure that the ground has good, smooth slopes away from where the location of the home will be.
Nyanzi says the key on this matter is to understand the site at the stage of site analysis. Take note of how surface water runs off when it rains and how the slopes are. This will help you provide for the drainage appropriately.
Drainage systems
There are two drainage systems that are required in a home. The foul water drainage and the rain water drainage systems.
The foul water is what comes out of your sinks in kitchen and bathroom and the rain water is those that fall off from the gutters and off into hoppers.
Many areas in Kampala have poor drainages, probably because the home drainage system is poorly designed.
“People trying to save money by taking shortcuts on foundation construction are actually throwing away money instead. Unlike walls in the super structure that can be easily repaired, mistakes in the foundation are usually guaranteed to stay forever with demolition of the houses as the alternative if any correctional actions to take place”, Nyanzi says.
Proper drainage
It increases stability of the ground, alleviates dampness in basements. If water is not properly drained away from the home’s foundation, it will pool around the outer foundation and contribute to a condition known as heaving.
Poor drainage
If you have a plot in wetland, many things should be done. You have to raise the house ground floors and it is also good to use hard core.
It is also good to create French drains around your plot. It will be good to fill all the trenches with hard core after cover them with soils on top.
Contributing factors to poor drainage
Clogged gutters contribute to foundational problems by causing water to spew over and overflow out of the gutter to accumulate around the foundation of the home.
Improperly angled downspout drains also contribute to water accumulating around the home’s foundation.
What can go wrong?
Nyanzi says if foundations are not properly drained, they can collapse completely causing loses to the owner.
The risk is higher in foundations that form basement or go-downs. If one of these goes down life could also be lost.
Poor drainage of foundations can cause continuous dampness in the house. “The floor keeps pushing water or moisture to the surface. As a result, you find water accumulating under carpets, furniture and other house hold items that are left lying on the floor”, Nyanzi says
Damage to walls, the creeping dampness can cause walls and wall finishes to get destroyed. Plaster could start crumbling, paint peeling and timber claddings rotting.
Nyanzi says in some cases due to extreme dampness in foundations; cause the house to start sinking. It starts sinking slowly because it gets very soft.
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