Silicone Resin Emulsion Paints: Tested on a “Living Object”
For us at WACKER, it’s always exciting to see how our products actually perform in real life. Consider, for example, silicone resin emulsion paint, which was first patented in 1963. In 2003, our colleague Dr. Heinz Geich decided to paint the exterior walls of his house with it. What does that look like 20 years later? Let’s have a look!
Exterior Paints in Comparison
Acrylic paint:
Forms an intact film, good moisture protection, poor breathability.
Silicate paint:
Porous surface, very good breathability, poor moisture protection and poor color consistency, if not modified with hydrophobic additives.
Silicone resin emulsion paint:
Forms a hydrophobic, vapor-permeable system that is weathering-resistant and extremely durable.
Anyone who has ever built a house knows that, as the builder, at some point you automatically become an expert in the best materials and techniques to use. It was no different for our colleague Heinz Geich when he built his house in the idyllic town of Marktl am Inn in 2003.
In his case, however, there was an additional factor: by virtue of his role as technical service manager in the WACKER SILICONES building protection team in Burghausen, he was already “predisposed.” In other words, he was fully aware of the importance of effective facade protection. “We wanted a solution that would permanently protect our facade and look good for years to come,” he recalls today. “When you’ve just moved in, you don’t want to be thinking about renovating again straight away.”
Silicone Resin Emulsion Paint Wins Out
The Geich family’s house was built in brick in 2003 and then plastered and painted. The bricks and plaster were not given any special treatment with an impregnating agent. “For protection against water and moisture, we opted instead for a outer coat of silicone resin paint,” says Geich. “Our painter, too, recommended it to us as the most modern form of facade protection back then.” And as a WACKER employee, I naturally had every confidence that our products would deliver on the promises that we make every day,” he adds with a grin.
“Silicone resin emulsion paint was recommended to us as the most modern form of facade protection. And as a WACKER employee, I naturally had every confidence that our products would deliver on the promises we make.”
Dr. Heinz Geich
Silicone Resins: The Network Holds the Key
Silicone resins protect mineral surfaces against water, without impairing their water-vapor permeability – and they do this reliably and permanently. The silicone resin forms a UV-stable and water-repellent network within the paint. The paint is permanently protected against water ingress, but is still able to breathe because water vapor can continue to pass through it. So, on the outside, the brickwork is protected against moisture and, on the inside, natural water vapor is able to escape unhindered.
SREP®: The Best of Both Worlds
Silicone resin emulsion paints (SREP®, Silicone Resin Emulsion Paint), patented by WACKER in 1963, combine the outstanding properties of mineral and synthetic-resin-bound paints: very high water-vapor permeability, extremely low water absorption and extreme durability. All these properties stem from the silicone resin binder that we at WACKER market today under the brand name SILRES®.
| Dispersion Paint | Silicate Paint
(Not Hydrophobized) |
Silicone Resin Emulsion Paint | |
|---|---|---|---|
| Surface/structure | Intact film | Porous surface | Network structure |
| Moisture protection | Very good | Poor | Very good |
| Breathability | Poor | Very good | Very good |
Ask our experts!
Do you have questions about silicone resin emulsion paints from WACKER or are you looking for the right product for your application? Our experts will be happy to advise you!
Contact us nowThe Paint Job Has Lasted. But Is it Still Delivering on its Lasting Promises from 2003?
A great deal has happened since Heinz Geich had the outside of his house painted with silicone resin emulsion paint 20 years ago. The family moved in and set about making the garden bloom. 20 summers and winters came and went. And the exterior paint? It has lasted.
At least, at first glance. But is it delivering on the lasting promises made back then? Heinz Geich wants to know. And so he invites us to carry out a few tests on his exterior walls and put the 20-year-old paint job through its paces.
Test 1: Abrasion – No Sign of Chalking
One measure of the durability of silicone resin emulsion paints is their mechanical strength. Chalking is the formation of a fine white powder on the paint surface. It is caused by weathering and leaching of the binder to expose the pigments and fillers – and indicates deterioration. There is no sign of this on the exterior wall of the Geich family home as he repeatedly runs a sponge over the wall. Chalking? Nothing. No fillers or pigments stick to the sponge. The “durability” promise has therefore been kept.
Test 2: Water Beading – The Droplets Keep Forming
To test the beading effect of the paint, Heinz Gleich sprays the wall with water. It is soon obvious that the paint is doing a lasting job of keeping the house dry. Instead of soaking into the wall, the water droplets simply roll down it – entraining any dirt particles along with them. “It’s like a self-cleaning effect,” says a delighted Gleich. “Every time it rains, my outside walls automatically get cleaned. No need to reach for the pressure washer!”
Test 3: Karsten Tube – Not Even Cracks Are a Real Problem
What about water getting in through cracks in the wall? Wait a minute, cracks? Lo and behold: there are hairline cracks here and there in the plaster. But Heinz Geich is unfazed: “Nowadays, it’s standard practice to incorporate a nonwoven into the plaster to prevent cracking. That wasn’t done back then, so it would be quite normal for hairline cracks to have appeared over time, for example due to movement in the walls.”
We want to know if this affects capillary water absorption by the wall in any way. So, Heinz Gleich carries out a test with a Karsten tube. This is designed to simulate a downpour in strong winds. What happens? The water emerges from the crack below the tube. In other words, it does not penetrate into the depths of the brickwork. The crack acts almost like a drainage channel. The silicone resin paint can therefore still be relied on to keep water out, even from cracks. Paint flaking around cracks in exterior walls painted with film-forming systems is a common occurrence, but not here. “The cracks in the paint are essentially deactivated by the silicone resin. So this is purely an aesthetic problem,” says Geich.
Test 4: The North-Facing Wall – No Moss in Sight
Shaded, north-facing walls are particularly likely to become disfigured by algae, lichen and moss – and even mold. These are all unmistakable indicators of permanently damp walls. For, no matter how good the paint is, no exterior paint provides 100% protection against condensation. The paint system therefore needs to be highly permeable to water vapor. This is the only way to allow the wall to dry out completely.
Heinz Geich leads us around his house and shows us the north-facing wall. Disfiguration? Algal growth? Nothing. On the contrary, the wall looks almost the same as it did 20 years ago. That’s a sign it is dry through and through. “The paint job still looks great. But to be honest, the silicone resin emulsion paint has far exceeded our expectations in terms of performance,” he says.
The Economics Are also Right
In 2003, the silicone resin paint alone cost 300 euros more an alternative standard paint. However, that extra cost would barely have shown up in the construction costs. Proving the motto ‘If you use cheap paint, you’ll end up painting twice – when it’s time to do the first renovation after a few years’, this small additional investment has already paid for itself several times over.
“The painter back then put it in a nutshell: If you use cheap paint, you’ll end up painting twice – when it’s time to do the first renovation.”
Dr. Heinz GeichRenovate the Exterior Wall? No Need!
The fact is that the use of silicone resin emulsion paints cuts out every second round of renovation on the average. This saves not only on the money for buying the paint, but also on the costs that make up the lion’s share of any exterior paint job: tradesmen’s wages, preparatory work and scaffolding costs. The carbon footprint of a facade renovation should not be neglected either. Over the long term, therforee, silicone resin emulsion paints are definitely economical and sustainable.
Heinz Geich’s own observations corroborate this. “In our neighborhood, many exterior walls dating from the same period have been painted, some of them several times, but our original paint job is still delivering for us, even after 20 years!”
Silicone Resin Emulsion Paint – Invented by WACKER
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