Plyboard vs Chipboard as a sub-floor

As a professional wood floor installer of over 15 years, I’ve got some strong opinions about different sub-floor materials. Two sub-floor types that I see often are Plyboard and Chipboard. In this article I’ll be looking at both and giving you some insight as to which one is the best..

We will be comparing the like for like cost per square metre, the usability, durability, quality and finally I’ll be summarizing what I think of these too products to hopefully give you a clearer picture while you’re considering an adequate material for your sub-floor.

Like for like cost

Let’s look at the cost per square metre between 18 mm thick structural plyboard and moisture resistant treated tongue and groove chipboard. I’ll be basing this on 18 mm thickness sheets as this is the minimal ideal requirement for sub-floor materials.

Structural Plywood 18x1220x2440mmStructural Plyboard – A sheet of 18 mm x 1220 mm width x 2440 mm length, currently at around £28.85 per sheet (Please note, square cut ply may require support noggins along the edge of the ply from joist to joist. Tongue & Groove ply will not require support noggins at these points). This gives a price of £9.69 per square metre. Amendment (24th March 2014) in relation to current improvements in sub-floor ply. Certain issues with cheaper standard ply has lead to the creation of sp101 plyboard which is fast becoming the recognized choice within the industry for acceptable sub-floor ply. This has been developed in recognition of blurred lines with regards cross use of different plywood products and given a definitive particular sub-floor plywood product.  

Tongued and Grooved Chipboard FlooringTreated Chipboard – A sheet of 18 mm thick x 600 mm width x 2400 mm length, currently at around £9.32 per sheet. This gives a price of £6.47 per square metre.

WOW! Has your mind just been made up? Well, I urge you to wait a couple of more minutes and read the rest of this comparison. There’s good reason for this price difference and you should be fully aware of this on a practical level before you go clicking that button.

Usability

You’ll find the usability of both these sheet products very similar although the plyboard has square edges and the chipboard often comes with a machined tongue and grooved (T & G) edge for each sheet to interlock. They both cut relatively easily although I find the chipboard gives a far finer dust. I’d always certainly recommend wearing a mask when cutting either.

Plyboard is essentially several thin real wood veneer sheets glued together and can often splinter slightly on one side while cutting, however, I would not consider this an issue as we are talking about a sub-floor product that will be covered and rarely chips to the point that it would lose it’s integrity. When handling plyboard, if you’re not careful it tends to be much easier to get a splinter stuck in ones hand than with chipboard although working with both materials can leave cuts and splinters if care isn’t used when handling them.

On the grand scale of things there really isn’t a huge difference between the weight of each. Often the range of sizes tends to be better with chipboard as it’s manufactured for the purposes of a sub-floor material and often comes in 600 mm width for ease of maneuvering within a home environment and general handling, whereas plyboard is produced as a multi purpose material hence often comes in larger set sheets.

When installing chipboard, as mentioned, it is often machined with a T & G edge. This means it is installed by slotting together each sheet. When installing chipboard in this manner it’s always worth checking each T & G to make sure that no poorly machined tongues or grooves will obstruct the sheets fitting together. Damage is easily caused to the edges during transport and should also be checked for, as again any crushed parts of the T & G can cause obstructions. Damage rarely happens to plyboard as it is a solid sheet material with no fine edges to damage and does not lock into itself as with chipboard, so any minor damage is often not a huge issue. For this reason alone plyboard is much faster to install.

Durability

From past experience I have always found plyboard to be the most hardy of the two materials. Even with chipboard that has been treated to resist moisture, it will often still swell, eventually rot and become weak after constant contact with water. I have always found that plyboard is far more resilient to water for a longer period of exposure and doesn’t lose it’s structural integrity compared to chipboard. Don’t get me wrong, they’re both wood based products and whether they’re treated or not , given enough water, both will still often require replacing.

Chipboard seems to sag between the joists. In my travels I have noted this on many occasions. Very rarely have I seen the same happen to plyboard. Due to chipboard being made with compressed wood chips, it doesn’t have the same core strength as plyboard. When I go to look at an installation where I’m installing a wood floor on top of chipboard, I see the sagging phenomenon an unacceptable amount and find myself advising customers to either remove the chipboard or look at ways to strengthen it. Have a guess what material I advice to strengthen the chipboard, yep, plyboard.

Quality

I judge quality of a sub-floor on several factors. Strength, longevity and sound.

It’s clear to me that plyboard is by far the strongest of the two products. To give a clear comparison, when installing a solid wood floor directly to a sub-floor, It’s a widely recognised fact that the secret nailing method cannot be used when installing on top of chipboard as it isn’t made from a strong enough material to allow the fixing nails to hold. Plyboard has more than enough core strength to hold fixing nails.

Plyboard certainly has longevity. It doesn’t tend to sag and, as mentioned, will often deal with water far better than chipboard. Although replacement of both material may be required if subjected to too much water, I have always found plyboard to keep it’s strength far longer than chipboard. Chipboard can often become a hazard. I’ve seen many a foot go straight through it after being rotted away from prolonged moisture.

The bounce! Chipboard can and often does bounce. Either over time or straight away depending on the thickness and quality. Although, in over 15 years I’ve seen very few that don’t bounce in one way or another. This leads me on nicely to my next point..

If installed correctly, plyboard doesn’t creek! If installed correctly chipboard often eventually does! With the explosion of fast, newly build homes over the past ten years and the increasing use of chipboard as a cheap sub-floor material, I’ve seen the common chipboard squeak too many times. If you have ever experienced it, believe me, you’re not alone! The squeak is basically wood particles rubbing together due to movement. As chipboard doesn’t have the core strength of plyboard, as mentioned, it can sag between joists. With this sagging comes bounce, with bounce comes movement, and with movement comes the squeak! Do not be fooled by people that say the squeak won’t happen if you glue the T & G with pva adhesive. This will not solve the eventual squeak..

Summary

I think you know by now my opinion. Although you may be enticed by the cheaper chipboard flooring, I have to strongly advice you not to be. Chipboard really doesn’t cut the mustard.

Is a saving of around £3.22 per square metre really worth the future under performance of a chipboard floor. After reading this, I hope you’ve come to the right answer and I hope you’ve made the right decision, choose plyboard. Although I sound extremely biased, I am so with good reason and good experience of both sub-floor materials.

Have you arrived here due to a failed chipboard floor? We now have a dedicated website dealing with squeaky floors nationwide. Call over and take a look at our example video’s to see what can be achieved…THE solution! www.squeakyfloorsolution.co.uk

© Copyright 2013 Wes, All rights Reserved. Written For: Fitmywoodfloor
About

I am a Pergo trained professional installer of 20 years. I've been up close and personal with lots of floors and have the knobbly knees to show for it...Should you have any questions or comments please feel free to add them below. Thanks for taking the time to call by and I hope the information you've found has given you some insight!........................................................................................................................................................................“When you click on links to various merchants on this site and make a purchase, this can result in the site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network, amazon.com, amazon.co.uk, amazon.fr, amazon.de, amazon.it, amazon.ca, affiliate window network.” This statement is to comply with current internet regulations regarding transparency to consumers.

Posted in Problem floors and poor installations, Sub-Floor preparation
  • Lauma Lauma

    Hi there,
    I found your article very helpful. However I need a bit of an advice regarding a situation we have and so far my searches over the internet haven’t returned much results. We have room that has had raising damp issues and that we are looking to renovate and hope to finish in hardwood. At the moment the floor is concrete so I would like to know how to go about the different levels of things to install. As I gather we would need to have a tanking/vapor/damp membrane on the floor first to prevent any moisture getting to the wood above it. But what do we do after this? Plywood subfloor? How to go about installing it on top of the membrane (as I assume nailing or screwing through it will damage it?). Any words of advice would be greatly appreciated as we are desperately tying to save on any costs possible. Many thanks, Lauma

  • Hi Lauma,

    I’ll gladly help the best I can. Firstly, can you tell me what type of room we’re talking about, more specifically below or on ground level?

    What is the sub-floor material at present?

    How old is the property?

    Regards,

    Wes.

  • Lauma Lauma

    Hi! Thank you so much for responding! It is a ground floor garage conversion (hence all the raising damp problems) and at the moment it is just concrete that is on the floor. It had carpets on it when we moved into the property however those all had to be thrown out due to the raising damp issues so we are looking forward to sorting it out for good this time and would like to have a wooden floor instead as we have an allergy prone child and dust mites just LOVE carpets! Oh and the property is 1960ties bungalow. Kind regards, Lauma

  • Hi Lauma,

    Thanks for clarifying.

    Okay, so the first choice you need to make is whether you’ll be having a ‘floating’ floor or ‘directly fixed/bonded’ floor.

    As a brief outline that will be relevant to your circumstances :-

    ‘Floating’ floor …Typically an engineered wood board (Not solid wood – there are some exceptions) –

    Pro’s – Easier to install. Quicker to install. Easier/cheaper to deal with problem sub-floors i.e. concrete without a mechanical DPM in place.

    Con’s – Can sound a little clacky under foot.

    ‘Direct Fix/Bond’ floor …Typically solid wood and most engineered wood floors –

    Pro’s – Once installed, will ooze quality. A firm solid feel under foot. No bounce, no clacky sounds. Quality!

    Con’s – Often expensive to prepare the sub-floor. Requires a deep technical understanding of sub-floor preparation and almost compulsive detail when it comes to the execution. Easy to miss something out and the floor to fail dramatically. Certainly requires an experienced installer.

    Let’s start with these two choices Lauma and take it from there 🙂

    Regards,

    Wes.

  • Lauma Lauma

    Floating floor it is please 😉

  • Great. I’ve got to go out and see a client, but will edit this post asap with an idea of an approach for you.

    Regards,

    Wes.

  • Hi Riko,

    They are a very narrow centre . However, I still think I’d opt for thicker that 12 mm. Trada.co.uk stipulate 15/18 mm thickness ply over joists. For the sake of a 3 mm difference, I’d opt for 18 mm ply. Indeed, for the sake of a 6 mm difference between the 12 & 18 mm ply, I’d opt for the 18 mm ply. Are you really going to notice a 6 mm difference?

    Hope that’s of some help Riko. I think we may have spoke before, apologies if this is referring to an earlier conversation that I’m not picking up on it.

    Regards,

    Wes.

  • Riko

    Thanks, Wes. I think you are right; even though head height is under 2.3m, doubt it’s worth taking the risk for the sake of 3-6mm. 18mm OSB/3 is what will be used in the loft (for 450cc), so i think i’ll just stick to that for the rest of the house too.

    We haven’t spoken before, but you may be thinking of a message i sent regarding Pergo Sensation vs. QS Impressive (which is still pending i think). But, anyway, i am going for QS Perspective simply because i like the plank better.

    Thanks again!

  • I think you’re making the right decision with the 18 mm OSB Riko.

    My apologies if I’ve not replied to your previous message. I’ve got a large number of messages pending and yours must have slipped through the net. QS Perspective is a solid choice, of which I very much doubt you’ll be disappointed with.

    All the best.

    Regards,

    Wes.

  • Hi Bill,

    Glad you found the article of use.

    If chipboard can be used over stilts, I see no reason why ply can’t be. However, we’ve never actually installed ply over stilts, therefore, I would have to advise you contact the manufacturer of the stilts to fully answer your question.

    You should try and incorporate a 2 mm expansion gap between sheets and 10 mm expansion gap around the entire perimeter.

    Regards,

    Wes.

  • adam

    Hi Wes i wonder if you could give me some advice.
    I am half way through building a new 2 story extension which comprises of a kitchenlounge with bedrooms above.

    I would like to stop any squeaking in the new floor as well as stopping noise transfer from below, so having read your views on chipboard flooring i have decided to install wisa spruce 22mm 2400 x 600 T&G ply onto the new 8x 2 joists.

    I note you have mentioned ms polymer glue for the installation of the floor in your yoga studio article but can only find glues that are trowled on.
    so i have the following questions –

    1. Would you recommend 22mm T&G wisa spruce ply
    2. What glue should i use & should i apply to the joist & T&G – is there a specific glue for the application ie fixing ply to joists?
    3. Should i screw or secret nail T&G joints – how many fixings per board?
    4. Is there a particular brand of passivated screw you recommend?

    I have spent weeks trying to decide what the best option is as i have 50 sqm to fit so appreciate your input so i get the correct materials.

    Great site by the way.

    Kind regards,

    Adam

  • Hi Adam,

    In reply :-

    1. Absolutely. Great choice!

    2. You could use an ms polymer adhesive such as ‘evo-stick serious stuff’, which is a fantastic adhesive. It has a number of qualities relevant to this application. It will act as a gasket that will help absorb a certain amount of impact, will flex to allow for expansion of the ply, and grab/adhere to prevent movement. The adhesive should be solely applied to the joists one board at a time. We tend to only do two methods of fixing. However, you also have the option of a third by applying D4 pva to the T & G. Do remember to leave room for expansion around the perimeter.

    3. Screw (In conjunction with the adhesive). Five screws per joist row. This will naturally make sense as you’re doing it.

    4. No.

    Additional advice – We tend to install our plyboard in a remedial context. Therefore, to avoid any potential of movement, we cut the ply on the lengths to have each short end finishing on a joists. You don’t have to follow our method but I think it was worth mentioning.

    By far, you are choosing the best option. Trust me!

    Thanks, the site has been hard work but well worth it 🙂

    Regards,

    Wes.

  • Hi GP,

    Tongue and Groove Ply.

    Regards,

    Wes.

  • Hi Jwoolard,

    For height consistency purposes and for the fact that you may have to cut close to walls where the floorboards are beneath partition walls, essentially meaning small sections of the floorboards will still be in play, I’d go for 25 mm thick ply. If square cut, supported at each join across the span of the joists. That may make more sense when you’re installing.

    If installing LVT, you’ll want to use a micro topping (feather compound) over the ply. Where any floorboards are, again, in play, you’ll want to make sure they are flattened out. This can often be done with a combination of sanding and micro topping compound. Alternative, you could apply a layer of smoothing compound over the lot. If you go for this option, be sure to dam around the perimeter to prevent the smoothing compound from escaping. This is particularly important should the room be on or above the 1st floor, as escaped smoothing compound can find its way down below room walls and make a right mess (especially if decorated).

    I hope that’s of some help.

    Regards,

    Wes.

  • Anthony Joseph Stokes

    Hi mate, what would be the problem using 18mm shuttering ply as a subfloor instead of structural ply? I intend to use full sheets of birch ply, screwed down on top as the actual floor. Cheers.

  • Hi Anthony,

    To my knowledge, shuttering ply is non-structural, has a lower grade adhesive, and is typically of lower grade wood. In other words, produced as a temporary board or one that would not be suitable in a structural application. For your purposes, it needs to be structural.

    Would the earth end should you use shuttering ply? Who knows. I can say, if it does go wrong, you’ll deeply regret doing this on the cheap.

    I hope that’s of some help Anthony and all the best with your up coming project.

    Regards,

    Wes.

    P.s. Don’t forget all the noggins between boards/hoist spans.