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Gurus To Get Grips With Chipboard

Martin Cummins reports on CFA manufacturer meetings

THE CFA manufacturers’ meetings give a great opportunity for discussion among representatives from the various manufacturers involved in flooring.
They include floorcovering manufacturers as well producers of adhesives, screed manufacturers and those who make moisture testing kits.
The pool of knowledge available from both the technical and sales sides is vast and on the occasion that we all open up the conversation we can get to grips with ‘real’ industry issues and concerns.
Over the last 18 months identifying and addressing issues relating to poor quality and consistency of plywood entering into the overboarding market has resulted in what is effectively a new standard being ‘created’ for flooring grade plywood … notable SP101.
A recent meeting looked at whether the same can be done with chipboard. Can we create a standard, can we engage manufacturers to create a product suitable for flooring and what work will be required to enable this to happen?
A decent discussion then ensued on what issues were presently being found and also what approaches manufacturers generally take at present.
My background in technical support and training means I am always looking at what may go wrong and how to avoid things going wrong…a sad approach to be fair, but that’s the role requirements.
So what do I believe to be the ‘issues’ with chipboard and why is it such a problem. The answer in my opinion is three-fold.
Firstly, the nature of the chipboard itself.
Secondly, the site conditions where it is installed.
Thirdly, the method of securing the chipboard.
A definition of chipboard would be: Chipboard (particleboard) is an engineered wood product manufactured by binding wood particles together with a synthetic resin which is then pressed together under high temperature.
Chipboard by design is an excellent product for creating a robust floor that can take trafficking and has a good resistance to compression. In other words, it supports materials applied above it.
However, the actual surface itself is not particularly strong as it is made up from compressed materials that may be pulled out of the bulk of the board. This means that flooring materials bonded to it need to have, in my opinion, a degree of ‘give’ under the loads being applied to the flooring.
As long as the right flooring system is used then chipboard itself may not be such an issue… long as it is flooring grade, fixed properly, conditioned and without surface treatments.
When we refer to flooring grade chipboard it is generally referencing products that are classed as moisture resistant or P5. Typically these types of boards are coloured green and stamped with P5 on them.
The moisture resistant element is key because in most situations the materials we are applying contain a fair proportion of water, whether they be primers, smoothing compounds or adhesives. Also knowing there is a consistency in the product helps when developing materials to function in tandem with the boards.
The most difficult recommendation to offer is when the chipboard is installed as a ‘floating’ floor. Often this is over insulation and sometimes over acoustic layers with the chipboard simply adhered together at the tongue and groove.
Presently this is a situation where most material manufacturers will not recommend bonding flooring materials as there is no way in which the movement in the chipboard can be automatically compensated by the flooring systems. The movement can be through loading on top of the chipboard or could be due to temperature or moisture changes in the building.
Specifiers will normally advise that chipboard be mechanically secure to the substrate using screws, not nails (they will work loose over time). Typically the boards should be screwed at 150 to 200mm centres; however, this is not always possible when joists are 300mm apart!!!
Moisture changes in chipboard are, in my opinion, the main enemy to the flooring contractor. Normally chipboard is not laid by the flooring contractor but has been installed in the building by a different trade. Their requirement is simply to get the floor down with no real concern as to what may be required down the line.
This results in damp chipboard being installed which only truly dries out once the building is an occupied stable environment. Even if it arrives on site dry it will undoubtedly suffer under other trades and inclement weather (chipboard often is installed prior to windows being installed and sometime upper floors have been completed).
As we all know in flooring these days, the flooring projects are carried out well before the building has been fully acclimatised so it is at risk too as and when the chipboard shrinks on drying. A method of testing the chipboard for suitable dryness prior to laying may be a good starting point.
To address this specific issue, chipboard manufacturers now produce materials with protective coatings to give, typically, a 28 day grace from inclement conditions and trades. The boards do not suffer from moisture ingress as they have a protective film or a coating applied. Great news for the boards, but not for the flooring contractor who now has a board of unknown surface to try and bond to.
The coating may not be easy to adhere to and the protective film may leave an adhesive which poses problems….so one problem solved perhaps but another one created.
Another major concern for me is when chipboard is utilised in situations with underfloor heating. This is something of which we need to gather more understanding before offering recommendations.
So we know chipboard is here to stay and in itself is a cost effective and, from a building point of view, technically effective flooring substrate.
It may not be such a massive concern provided the key aspects are all met, including that it is flooring grade, stable in a stable environment, screwed and fixed to offer no deflection at joints or lateral movement.
The issue then is securing materials to it…..and this is our challenge as manufacturers. Is it best to use a lower strength softer bag and bottle system or a fibre reinforced water mix when smoothing over?
Should we prime, if so with what type of primer? Can floorcovering be bonded directly or will there be issue with joint grin through? UltraFloor will have its own thoughts as no doubt all manufacturers will and by working together we can hopefully come up with recommendations that have an excellent chance of success.
Martin Cummins is Ultra Floor technical sales manager

T: 01827 871871

This article has been reproduced from the Contract Flooring Journal website. You can find them at