Even board surface
There are some conditions that affect the surface of the boards and these should not generally occur in timber
fl oors. However, fl oors exposed to heat sources after occupancy (e.g. no curtains, fi replaces, vents from
appliances, houses closed up for extended periods) may cause movement in the fl ooring resulting in effects
such as gapping. Similarly, changes that affect the conditions beneath a fl oor can also result in board movement
and shape changes resulting in cupping. It should be noted that the actions or inaction of owners and builders
can contribute or even cause these effects to occur. Therefore it is benefi cial for fl ooring contractors to make
builders and owners aware of aspects that could affect their fl oor and that any concerns that the builder or owner
has, be brought to the attention of the fl ooring contractor at an early stage. Product choice, particularly in terms
of board width will also infl uence movement after installation, with wider or thin boards often being more prone
to some cupping and gapping in a dry internal environment. The conditions defi ned below should however not
normally occur in a fl oor and if they do, remedial work is often necessary.
Cupping – boards with their edges higher than the centre of the
board. Moist conditions beneath a fl oor can cause cupping and
heat in a specifi c location or a very dry environment above the
fl oor can also cause boards to cup. Cupping is more likely to
be observed in overlay fl ooring and in wide standard thickness
boards. To some degree a small amount of observable cupping
may occur in some locations where these types of fl ooring are
used (e.g. sun exposed fl oor).
Peaking – This has the appearance of cupping but is the result of
expansion pressure in the fl oor. Again it is generally expected that
a fl oor would be free of observable peaking.
Tenting – This is not acceptable and occurs when the adjoining
edge of two boards has lifted above the level of the adjacent
fl ooring. This is often associated with high moisture beneath the
fl oor and can be from a number of other causes.
Buckling – This is not acceptable in a fl oor and occurs when a section of fl ooring containing a number of boards
has risen above an adjacent section of fl oor.
Crowning – boards with their edges lower than the centre of the board. This is not acceptable and occurs when
a cupped fl oor from moisture effects has been prematurely sanded. Crowning may not become apparent until
some months after fi nishing.
Gapping at board edges
Gaps at board edges do not necessarily constitute a problem with a fl oor and simply refl ect seasonal changes
in weather conditions. Shrinkage gaps between boards may average 0.75 mm for an 80 mm wide board fl oor
during drier times of the year or dry internal conditions. For wider boards, proportionally wider average gapping
can be expected. Therefore owners of wider board fl oors need to be more accepting of gaps as this simply
refl ects the natural response of timber. Some gaps will be larger than the average and others smaller, however
the appearance should generally indicate gapping between most boards. An appearance can be expected that
is free from irregularly spaced wide gaps across the fl oor associated with edge-bonding (the fi nish gluing groups
of boards together). The provision of expansion gaps as part of the installation process and evident throughout
the life of the fl oor is acceptable.
Vertical movement at T & G joints
Flooring is manufactured with the board tongue narrower than the groove. This is necessary so that boards
will fi t together during installation. When fl oor boards are laid over joists or battens, some differential vertical
movement may occur between adjacent boards when there is foot pressure on an individual board. This is due to
the clearance between the tongue and the groove. The clearance should not exceed 0.6 mm to comply with AS
2796 Timber – Hardwood – Sawn and milled products, but with this tolerance movement will be observable.
A small amount of noise can be expected from most timber fl oors when walked on. Noises can occur from
movement of one board edge against another or from boards moving on nails. A fl oor is often more noisy during
drier weather due to loosening at the joints. A fl oor that squeaks excessively requires remedial action.
Timber strip fl oors can be expected to show some indentations depending on the hardness of the species used,
variation in density, volume of traffi c and type of foot ware worn. Softer timber will indent more readily than harder
When timber fl oors are laid direct to concrete slabs, drummy sounds can occur under some boards. When there
are a limited number of instances associated with one or two boards in some areas of the fl oor, and no vertical
movement when pressure is applied, remedial work is unlikely to be required. Refer to ATFA Information Sheet
No. 6 Hollow Sounds.
Acceptable Floor Appearance
Timber Colour, Grade and Species
Within a single species the colours and colour variation can
be quite pronounced and can differ markedly from one fl oor
to another. It is also possible that a limited number of boards
of different species but similar in colour and character will
be present in some fl oors and this should not be cause for
concern. Through grading errors or when a fl oor is sanded, it
is also likely that some features will appear or be a little larger
than the grade description. There is however generally a clear
difference between a fl oor that is of the incorrect grade and a
fl oor where grade limits have been exceeded in some boards.
Such fl oors where the grade description is exceeded in some
boards should also not be a reason for concern. Refer to ATFA
Information Sheet No. 5 Floor Colour and Grade.
Board lengths and distribution in the fl oor
Board lengths are generally a minimum of 900 mm long when laid on joists or battens. When laying over a
structural sub-fl oor the minimum length may be shorter. Where possible end joints should not cluster together or
align. Generally, only one end join should occur in a group of three boards between fl oor joists. In the case of glue
fi xed fl ooring, it is preferred that end joints be a minimum of 300mm from end joints in adjacent boards.
The sanding process involves hand controlled equipment and due to this there will be some evidence of the
sanding process in the fl oor. It can be expected that the fl oor will be fi ne sanded and that edging will not result in
scalloping. Similarly it can be expected that corners will be scraped to an even surface and sanded to provide a
fi ne surface. As such sanding marks in the timber should not be visible from a standing position. Generally, the
viewing angle for assessment should be 45° from the eye to the fl oor.
At times there can be vibration that occurs which may be induced by the sanding machine or the sub-fl oor
framing. Although this vibration can lead to chatter marks in the fl oor, it would be usual to expect a fl oor free of
With the re-sanding of an older fl oor it must also be recognised that the sanding process will not remove existing
deep cuts or damage and that stains may also not be removed if they have penetrated deep into the timber.
Nail Holes and Filling
Unless otherwise requested, all fl ooring nails are to be punched below the surface and the nail holes are to be
fi lled. With solid T&G fl ooring it can also be expected that any gaps at board ends will also be fi lled. Filling at board
edges is generally not recommended except for parquetry where fl ood fi lling is to be undertaken and in some
instances with direct adhesive fi xed fl oors. When one colour of fi ller is used, that colour should match the darker
tone in the boards as with time the contrast generally becomes less.
Coating and Finishing
A fl oor is subject to much heavier wear than furniture and although a good quality fi nish can be expected, the
same fi nish quality to furniture should not be expected. There are a number of imperfections that are likely to
be present to some degree in a fi nished fl oor and the degree to which they occur, where they occur and the
presence of other imperfections, will determine their acceptability. When assessing the appearance of a fl oor
it is to be done from a standing position and the fl oor should be viewed at an angle of about 45°. Common
imperfections present to some degree in fl oors are outlined below.
Dust and debris – A degree of contamination in the fi nal coat is unavoidable and will vary from one site to another
being dependent on a number of factors such as draughts, heating and ventilation systems, insects and the like. It
can be expected that the contractor will take reasonable measures to minimise the risk of contamination and that at
job completion there will not be heavily contaminated areas in the fl oor that are obvious when assessing the fl oor.
Swirl marks – Swirl marks are caused by rotary sanders and to some degree will be present in all fl oors. Down
lights will highlight sanding imperfections due to light refraction through the coating and as such this is not
controllable by the contractor. Fine swirl marks that are not obvious under natural light when assessing a fl oor
should not be a concern.
Coat levelling – Rejection, orange peel and quilting all relate to unevenness in the coating resulting in either a
mottled effect or in the case of quilting discontinuity across joints. If instances are isolated, minimal in nature and
not in areas frequently viewed then remedial work is unlikely to be necessary.
Delamination – Separation of one coating from another or from the coating to the board should not generally
occur in a fl oor and in such instances remedial work is necessary. Minor delamination due to movement at board
joints or ends can occur and provided it does not progress, remedial work is unlikely to be necessary.
Gloss variation – Differing conditions in the dwelling at the time of curing can result in gloss variation. Although
consistency can be expected at the time of a particular application, some variation may be apparent between
areas when fi nished at a different time. Gloss variation within a room particularly with satin fi nishes usually
requires remedial work.
White lining – When gaps appear at board edges the stretching of the bridged coating can cause a white line to
appear at board joints. Unless severe this conditions requires no remedial work.
Lap and roller marks – Some fi nish systems are more prone than others and should lap or roller marks occur,
they need to be minimal in number and not able to be observed from all directions, to be acceptable.
Edge bonding – Some fi nish systems can act as an adhesive and bond board edges together. With shrinkage
in the fl oor, wide irregular spaced gapping and splits in boards can occur. Only minor edge-bonding resulting in
small gaps at board edges is acceptable. Frequent splits and wide gaps are not acceptable.
Ghosting – Lighter toned boot and foot prints can occur in fl oors 6 to 18 months after the fl oor has been fi nished.
In most instances the source of the mark cannot be identifi ed and in most instances not likely to be associated
with the sander and fi nisher. Re-sanding and fi nishing may correct the problem and a compromise between
parties is often necessary to resolve the problem.
Colour Changes to Timber and Coating
Over the course of time colour changes occur in timber fl oors from the
effects of ultra violet light. Therefore it is usually more pronounced in sun
exposed areas of the fl oor. This is partly associated with the changes
in the timber and partly with the coating that is applied. Some coatings
darken with time more than others and some timbers are more prone
to colour changes than others. This process is natural and gradual but
can result in distinct colour differences where rugs have been put on
the fl oor. Some of this change can be minimised by not putting rugs
down till six or so months after the fl oor has been completed. To avoid
severe effects it is benefi cial for fl ooring contractors to make clients
aware of how the coating used may result in colour differences. From
there it is up to the owner to manage how rugs are used.
This information sheet outlines reasonable owner expectations
for an onsite sanded and fi nished timber fl oor. This includes solid
T&G fl ooring, parquetry and other fl ooring types that have been
sanded and fi nished onsite or recoated. Concerning this, there are
performance aspects of the fl oor which generally relate to fi xing
integrity, board shape and movement, and then there are appearance
aspects which focus more on the sanding and fi nishing.
Although an imperfection free fl oor is the desire of any tradesperson,
it is the process of installation and fi nishing where the environment
and other conditions cannot be fully controlled that moves the
completed job to one that is ‘normal’ and of an industry accepted
standard. This however is not to say that the completed fl oor
won’t be of a high standard and well suited to its purpose as a
fl oor which is to be walked on, but it does acknowledge that the
fi nished product will not be the same as fi ne furniture and that
due to seasonal infl uences and heating and cooling, that some
movement refl ecting the nature of timber will occur.
Concerning the installation of the fl oor, the provisions are outlined in either the ATFA publication ‘Timber Flooring’
(2009) or specifi c manufacturer recommendations for their products. The sanding and fi nishing of timber fl oors
is covered by AS 4786 – Timber Flooring – Sanding and Finishing along with a general description of the process
provided in ‘Timber Flooring’.
Our expert floor sanders who use state of the art floor sanding machines can handle all resurfacing projects as well as new floors.