The importance of surface preparation.

This one is very, very dear to me and I talk about it a lot when I do talks to applicators, and in trainings, and our staff continue to do this, and it's in all our data sheets, yet it amazes me how many times we still see issues out in the marketplace, where applicators get it wrong, and I'm not sure why that is.

When we do training, we say there's three important things you must know before you start applying any product; surface preparation, surface preparation, surface preparation.

It is the key, reinforced time and time again, yet so often we see jobs when they fail. I'm not talking about specific products, it could be across the market. I've been out to many projects at times over the years and have seen opposition product being used there, and it would be a great opportunity for me to bag the opposition but I don't because the product is of good quality, but the problem is, the way the surface has been prepared before the application. And this is not just for remedial works, this is also for new jobs.


Let's talk about concrete first. Concrete. Sometimes there's additives in the concrete. Sometimes the way that the concrete cures, you've got a surface residue sitting on top. It might look sound and stable, but if I get a key, or I get a trowel, and I scratch into that surface, and I can start to see that it's not solid and hard, then, to me, obviously that means I need to look at grinding that substrate and taking it back to a condition or a stability where it is sound and stable.

I even see people, when they're putting self-levellers on floors, and I'm sure many of the flooring guys reading this can testament to it, where flooring comes up, because what happens is when you put a new product on top, there's a curing phase. If it's a cementitious membrane, or even a water based membrane, or a solvent membrane, or a 2 pack epoxy, or a 2 pack urethane, there's a curing process. What happens is, it'll give a bit of stress on the substrate. Now, if that's a real weak surface, and it's not solid and sound, you'll get a separation, and then that's going to continue, and then it compromises everything else.

So with concrete, make sure it's solid, sound, and stable. This information, that's on our data sheets, and on many other data sheets, is not there for just to take up space on a data sheet. It's there for a reason. Refer to it.


Then you've got to put the correct primer down, which we've gone through before. So this is not about primers today, it's about the stage before you prime. So concrete's one. If I've got things like pre-cast concrete or concrete that's been poured, particularly where you may have vertical surfaces and they've used form release agents on the formwork, or they've used things like diesel, sometimes there's a separation layer. It’s things that are not visible to the eye, you need to check.

So what we've said before about doing the water droplet test. Get a water misting bottle, mist some water on there, see if the absorption's happening. Ensure that the surface is reacting like it should be. If you start to see that you're putting water on a concrete wall, mist water on there, and it's beading, then there's something on there. It could be a wax residue, it could be a diesel residue, it could be something else, clean it. There are a number of degreasers out there. There are a lot of other good surface prep products. It might need a pressure clean, but don't just guess and think, "This will be okay," and put any membrane on it, because you are going to be ultimately responsible once you start laying that product down. That is critical.

Metallic Surfaces

Metallic surfaces, okay, galvanized iron, ZINCALUME, aluminum. When they're aged, you're going to make sure obviously they're rust free, and if there is rust or corrosion, treat the rust, because rust is like a concrete cancer. It'll continue underneath the coating. The next piece, though, is if it's new metals that you're going over, again, a lot of the new metals, in the factories when they come out, they have an oil release on them. So it's important that you might think, "I can brush a primer on there and it's sticking at the moment," but is there an oil residue on there? So take precautions, use a degreaser.

Cement Sheet

Now, cement sheet, unless you've got contamination or things that have dropped on there, it should react as it's designed for. But again, just make sure. There may have been guys that have been walking out on a deck or a podium, that have had all sorts of crap under their feet, and it might not be visible to the eye, and then you start rolling out primers and membranes and find that the membrane just can come up easily. Check the surface first. That extra 10 minutes, to a half hour, to an hour if it needs, of checking the surface prep, can save you a lot of money and time and your reputation. Risk taking is not where it happens.

There's two things I always see with good tradies out there; clean tools and clean surfaces. They get that piece right. If I walk on a site and I see the attention to detail that an applicator's gone to in getting his area right, making sure that it's cautioned off, there's no one walking in there, it's cleaned, it's vacuumed instead of just getting an old broom that's already got shit and dust in it, clean that properly, then you know that you've actually got someone who knows what they're doing. It gives me a lot of confidence in training these people, certifying them, and also recommending them. They're the sorts of little one-percenters that give away that an applicator knows exactly what they're doing. It's so important.

We talk about surface dust. Guys say to me, "Oh, I don't want to prime because of ... I'm just going to clean the surface down." You still, on some substrates, get surface dust, and a primer, after you've cleaned it, will lock that in. Just don't cut corners. It is so important on the surface prep.

If used on things like Dincel, which we've spoken about before, it's a plastic type surface, or a PVC, these sorts of surfaces need to be cleaned, then you look at the OP primer on top. Same if you're going over ... I see we've got our OP primer that's used particularly on tiled surfaces or glazed tiles, but if I'm going inside a shower alcove that's had people in there, I might have washed it down and cleaned it and dried it, but there's soap and scum residues on top of those tiles, that have they been removed and cleaned properly before you go and put a primer like the OP down on top of it, or an epoxy surface?

These are the little hacks that you just need to understand, not take the risk. It's very, very important. Get the surface prep right, and ensure that any of your guys that have got people in your workforce, that you contribute to and get them to actually do the work for you. Sometimes, I know applicator crews get some of the younger apprentices or other guys to clean the surface and prep it for the main guy to put the membrane down. Don't think that the guy who's just the laborer or the young lacky that's doing the surface prep is the one that he needs to understand what he's looking for and what he needs to make sure that can stand up to, so the guy that does come and put the membrane down, it's a surface that is in perfect condition, can handle it, and you rest assured, you sleep well at night, knowing you got full adhesion.

Really keen to hear more from you guys if you've got any photos or stories or comments about this one, surface prep. No one's going to convince me about shortcuts in this area. It is the main one you've got to make sure of in waterproofing. Get it right and you'll seal it for good.