Internal & External Waterproofing Methods In Construction – Which Is Cheaper & Better?
All structures must at one point or the other during their service lives, be subject to moisture. It is therefore, pertinent to take effective steps to contain water that may damage the structure during its service life.
There are basically two approaches used to waterproof buildings and construction works.
While the effectiveness of none of the methods can be totally annulled, a comparison of the two methods shows that one is cheaper, and works to contain water better than the other.
This is because the quality of DPMs available these days do not have the tendency to effectively control dampness in buildings.
Surprisingly, many engineers and construction personnel have gone the way of the other because they believe its cheaper.
A critical peep into these approaches actually debunks that this other method is not actually cheaper.
In my last post, I did mention that there are internal and external waterproofing methods. Many construction workers opt for the external method which entails the use of DPM polythene (nylons).
To make these DPMs serve well for the purpose of waterproofing, it is recommended to use double ply and they should overlap at least 150mm at joints. They should flush over grade beams or walls in order to checkmate moisture seepage at those points.
The other method is through the use of crystalline admixtures, known as internal waterproofing.
Many of these admixtures are available in the market, and the approach, is to mix a given proportion of the admixture with concrete during mixing and placing.
Examples include Dr. FixIt, Krystol Internal Membrane (KIM), etc.
Let’s compare these two methods for cost affordability.
Let us assume the price of DPM per square meter to be #400 and price of screed done on DPM to curtail DPM puncture to be #2,900 per square meter.
400 + 2900 = #3300 per square meter.
Let’s use KIM to calculate for internal dam proofing method.
Price for pail of KIM = #89,000
A pail 🪣 of KIM is sufficient for 50 bags of cement.
