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Particle board flooring

Many of you know it as yellow tongue, which is an industry terminology that's used out there. But particle board flooring has been around for many, many years in the construction industry. And somehow it found its way into waterproofing applications as a substrate for tiling and membranes in wet areas.

Its application is still a grey area. I'm going to give you my position on it, which is Gripset's position and how we handle it, and our thoughts and processes on how to treat particle board or yellow tongue flooring.

So firstly, let's look at internal wet areas. Most builders these days will use an inert material, inert meaning that it doesn't react to sustainable temperatures like cement sheeting, or compressed fibre sheeting, several other substrates out there that are of a synthetic base or your old form concrete that is used for wet area flooring. It's more stable and even though it still has to be waterproofed, it's not as volatile to temperatures.

Timber, for those of you who know it very, very well, is a living and breathing thing, okay? Almost like a bottle of wine. And so, very important to understand that, with timber, every time the temperature changes, you're going to have the timber move. Now, it's not visible to the eye, it doesn't move and flex to the point where you can see it, but small movement will happen in the substrate. So we have timber joists on building sites, but then we've got timber flooring.

Now, particle board flooring is commonly used in dry areas. Very stable for things like vinyl or carpets, but when we've got tiles and you've got something that's a solid, sound substrate in a wet area, and then you've got particle board flooring underneath, you need to be certain that, if it is the floor that you're going to be working over, there are precautions being taken to ensure that it's been fixed correctly. Now, all building substrates need to be fixed properly, I get that; however, if you're tiling over anything with particle board or timber flooring, ensure that it is glued and screwed, otherwise, you could be the latter: screwed.

Yellow tongue and particle board flooring, it doesn't always have to absorb water for it to move. It will find its way into a movement effect just from the thermal changes that happened within the building substrate, or within the construction. And what that does, it will compromise the finish on top. When you've just nailed timber flooring down, like you would in a dry area, then its fixing strength is a lot different than when it's screwed and glued down.

So get that piece spot on first. Then, you need to make sure it's a timber, which is designed for wet areas, and if you're not certain about that, ask your builder or your client and ensure it is. If it's not, you're taking a big risk to try and waterproof or tile over it in a wet area.

It's imperative to understand that if the timber flooring is not fixed properly and it's not the correct grade of timber for a wet area, do not take the risk. Now there are options in that situation, I've seen many tilers and waterproofers when they're faced with that situation they will perhaps nail cement sheeting down, thin hearty flakes, or the equivalent of that, 4 to 5, 6 mils thick, over the top it's a more stable surface which works like an underlay, and then they can put their waterproofing or tiling directly over that, it's very important.

Tilers or waterproofers must make sure that they have put some sort of cement sheeting underlay down on top of that flooring before they go and lay tiles or waterproof over the top to ensure that it is isolated from the surface. Otherwise, the particle board or timber will move and flex and compromise your finish, that's critical.

We do have our GC range, you have GC1 and GC2, that are used for anti-fracture systems for that, and the GC2 is more of a decoupling. It's a great option, and it's a lot quicker that nailing cement sheeting down onto timber flooring. Our choice for many tilers and waterproofing friends so, thanks for your support there, but the feedback has been that it's very, very quick and it allows you to just fly on and get your tiles down without all the noise of nailing every hundred mil of cement sheet underlay down. Different application again, but just going in terms of how to prepare the surface.

My preference is I would ask the builder or your client to ensure that you're going to get paid to take the precaution with a membrane like this over the top, or, as I said before, you put the cement sheet down on top of that before you start tiling directly over it because it's not so much that you're going to have a failing with the waterproofing, but you could have a failing with the tiles cracking, and that brings up the waterproofing, and it all compounds from there. So get that part right, I've just seen so many situations where I've seen timber, actually, mushroom out in applications, cause it doesn't just absorb the thermal moisture from the top, it's from the underside in the cavity, and that there would tend to change, creates the timber to react as it is designed to do.

The other piece is, which really concerns me, particularly when I see it in the winter months on building sites, these sorts of sheets are delivered on site and they're left outside, sometimes for a week or two before the carpenters start putting them inside, and, by that time, they've absorbed dew, rain, all the different moisture conditions that are outside. And then, by the time it's put inside it's already swelled, or absorbed a level of moisture. And so you actually don't know if you're going over a bone-dry surface. Now, there are moisture meters, very few people are using those, but these are the risks that I talk about that you run when you're waterproofing or tiling directly over them. So be aware of that one, it is a critical one to take note of.

Marine ply is a different type of timber, I do get that it's more stable than particle board flooring, from what many claim out there because it's not cheap board and such; however, I still would be very, very cautious in terms of how you treat that and how you approach it.

Now, I'm going to talk about the external piece. If you are finding yourself challenged, you go to a building site, and the client has timber on their balcony deck, it is red alert, do not even think about what primer's going to work and what I should be doing, you need to make sure that there's absolutely no chance in hell you're going to waterproof or tile over that.

If you do, be aware that all the risk is with you, and there's a major risk, because it doesn't matter what system you use and how good a job you do, that application is going to be at risk for the rest of the time it's out there, with the various thermal conditions outside versus an internal wet area, because you've got transfer of thermal conditions, whether it be the colder parts of Australia or the warmer parts of Australia, and as I said it's the atmospheric moisture that the timber will absorb from underneath in eaves and the cavity.

So, I don't believe anyone should be waterproofing over timber externally. Protect that substrate with a system like a cement sheet underlay first, and then waterproof it correctly, with one of our systems, and the outside now, for a longer time warranty we go to GC range, there are other systems there from other manufacturers that can handle the conditions for external panes or timber deckings, but do no run the risk of just putting a bit of sealant around there on the timber and then liquid membrane and taping the joints up and hoping it's going to work, because really, all you're doing is waiting for that phone call, the phone call you don't want, to go out and fix it again, and then it's all just a bitch-fight from there.

Get this right, warn your builder, warn your client if you see it, and explain to them that they run the risk as well, because I'm just saying this, the uneducated will give you a building where they've got this timber down, or plywood outside, and I'll just waterproof or tile it, it'll be fine. I don't know what people are trying to invent in that situation, but, at the end of the day, it's your reputation, and you're the one that's accepted the surface, and once you accept that surface, it's your baby and it’s a real ugly one to deal with once you accept that. So get that piece right.

Now, in terms of the challenges it presents for waterproofing, so, like anything, surface preparation we get right, but we judge the surface in the substrate, and once we know it is correct, and we can correct them, and it's suitable within the guidelines, because the thing is, if you go back to the manufacturers of all the supplies and the tinder, very, very gray in terms on what they'll state on the specifications for wet areas. You want to understand what they cover and what they're fixing manual is.

And so, I refer this many times with the James Hardie manual, I still find it one of the better ones and I'm not paid by Hardy to recommend their products but I find their manual, in terms of how to fix their deckings, whether it be scyon or compressed cement sheetings for balconies and decks is a great one to refer to. It's visual, they give drawings and there's a written specification and list in terms of how to fix joints, fix it to the joists, and how you treat it for the waterproofing recommendations. If timber covers can't do the same thing, then you should be asking the question "why not?".

And that gives you a lot of ammunition to discuss this with your client, so they understand where you're coming from. You're trying to protect them, and yourself, and make sure the job works. Imperative. Okay, so, if you've got any questions on yellow tongue, particle board flooring, when we've got a situation where we are tiling in an area that might not be a wet area, and there are good tilers that can handle the flexibility of the timber, we do use things like our Gripset OP, it bonds very well to particle board flooring, but in wet areas, please take caution, because we've seen this one come unstuck many, many times. And back in the day, when I started, I saw a lot of jobs where this was used on the outside and it had that mushrooming effect, doesn't matter how good the waterproofing is, you're compromised by the substrate below cause it just keeps moving and reacting.



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