Floor Laying Technicalities
THE ADVICE
PRE-INSTALLATION REQUIREMENTS:
A hardwood floor is a serious investment. It should last for one lifetime and possibly
several. Hardwood floors are things of real and lasting natural beauty which can add both
aesthetic and monetary value in excess of their cost to your home or office.
You must expect some disruption and inconvenience if you have a hardwood floor
installed in an occupied building. Make sure you give the flooring contractor the time he
says he needs to carry out the work without interference from other trades.
Remove from the room everything you do not wish to dust - all furniture,
ornaments,pictures, curtains, and old floor coverings should be removed from rooms where
flooring is being installed.
The building should be completely weather-tight, with external windows glazed and doors
fitted.
ALL wet trades (plastering, drylining, water based paintwork, ceramic
tile, etc.) should be completed and their work dry.
Air conditioning, heating and ventilation systems should be commissioned and operating
for at least 14 days prior to beginning hardwood flooring works.
The temperature and relative humidity must be at "normal living conditions"-
i.e. between 60 & 80 degrees Fahrenheit and between 30-50 percent humidity- for a
minimum of 6 days prior to delivery of the wood flooring.
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Preparation.
It is an old 'saw' that good preparation is everything. If you do not prepare the base correctly you will be very fortunate if you do not struggle to fit the floor and the quality of the finished floor may be seriously compromised.
Joisted floors . Ensure that the joists are sound, free of infestation and rot, particularly where they join the walls. In newly built works it is worth investing the extra little bit in kiln dried joists. Very many buildings, old and new suffer from joists which have shrunk after the building is finished. The floor drops away from beneath the skirting, leaving an ugly dark gap between skirting and floor. This is a difficult problem to correct or cover neatly. Once you have fitted the expensive hardwood floor it will be very costly to put right any inherent defects.If the joists are uneven in their height they may need to be 'firred' or packed. Firrings are strips of timber laid over the tops of the joists to equalise the levels accross the joists. Packers are used to lift the ends of sunken or shrunken joists to bring them level with their neighbours.
Board floors . When fitting over exisiting softwood floors it is vital to ensure the boards will provide a sound, flat, firm base. Lift any boards which are loose to check the positions of services (electricity cables, water or gas pipes etc.) and then refix, marking the services positions on the face of the boards.
N.B. Never put fixings through boards if you have even
the slightest suspicion that there may be services below. Murphys
Law dictates that if there is something there you
will definitely hit it with the only nail or screw which penetrates
the underside of the board and you will not know about it until
you have laid and finished the whole floor and the damage will become
most evident just as you and your family are about to set off on
the most expensive holiday of your life - or the damage will greet
you as you open the front door when you get back and your neighbour
says, "I wondered why there was a constant stream of water running
out of your front door all month, but I did not want to interfere.
What a shame."
Walk the floor, taking note of any creaks or movements, particularly in doorways. Screw down loose or creaking boards. Use screws instead of nails because they hold firmly and can easily be removed. If screwing down does not cure the creak, take up the section and investigate the cause.
Sand the floor smooth and flat if it is uneven or the boards are badly curled.
Fit overlay boards at an angle to the run of the exisiting boards - either
obliquely (45 deg, 60 deg.), or across (90 deg). A satisfactory
result is sometimes achieved with new boards overlaid in the same
direction as the existing boards, but these are the exceptions to
the rule. If this procedure is carried out it is common to find
that sooner or later the new floor copies, even exaggerates, the
undulations of the floor below.
Many parquets, particularly 6mm, 8mm, and 10mm thicknesses, are
fitted over a plywood subfloor of the same or greater thickness.
Fit plywood underlay sheets with slightly open joints so that there
can be no possibility of the edges of the plywood rubbing together.
Fit plywood with screw nails or screws at regular intervals suited
to its thickness. This may be at 150mm centres.
If fitting 18mm plywood bases over joists then joints should either be tongued and grooved and glued or, if square edged, set at a couple of millimetres gap between sheets. Do not forget. You cannot easily cure a creak in the subfloor once the parquet is fixed and finished.
Screed bases. . Screeds must be sound. This means they must not be cracked and breaking up. They should be non-dusting. It is difficult or impossible to achieve a good adhesive bond to a dusty screed. If the surface is friable it should be sealed with a suitable binder - PVA, polyurethane, or epoxy damp proof membrane. The surface should be flat and level to within 3mm + or - over 3 metres in any direction. The screed should be free of snots of cement or plaster etc.
Acclimatising the timber.
N.B. David Gunton, our consultant parquetier,
is not an enthusiast of acclimatising timber floorings for every
situation. However, he concedes that there are situations
where it is useful. Further, he recognises that there is
still a long standing overhanging belief that acclimatisation of
the timber to the site is the 'old fashioned' craftsman's way of
doing things and therefore must be correct. It is hard to
break down ancient fallacies. Acclimatisation of timber is
a wide ranging subject upon which volumes can and have been
written.
You should order flooring kiln dried to the correct moisture content
for the building. This will be at 8 to 10% average moisture content
for most modern or well modernised buildings. The lower range will
apply for floors with underfloor heating. Modern buildings have
a high level of atmospheric stability. This is created by
good ventilation, by draught free windows and doors, central heating
and insulation. However, in an unrestored draughty Victorian
vicarage, with single glazed sash windows and coal fires, beautifully
situated in water meadows by a river, you would want the timber
flooring delivered at around 12 to 14% average moisture content.
Do not acclimatise the timber to building site atmospheric conditions.
It is no good acclimatising timber to conditions which are not
as they will be when the building is in occupation. If you are not
confident that the conditions are correct, do not acclimatise kiln
dried timber but keep it well wrapped up - top, bottom, ends and
sides - until you are confident!
If you are confident of the conditions, but not confident of the moisture
content of the timber, the timber floor should be allowed to acclimatise
in the rooms in which it is to be installed for 3 days or longer.
A lot depends upon the time of the year and the weather conditions
prevailing. You should ask the floor contractor to test the moisture
content of the flooring before the floor is laid and record the
readings.
Be sure you understand how long the installation and finishing will take. Very broad
guidelines suggest you should allow approximately one eight hour man day per 2.5 sq.m. of
floor to be laid and finished. However, border takes much longer to lay than the field of the floor,
and corners take more time than the straight run of the wall. So, a 30 sq.m. long narrow
Victorian style hallway with lots of corners and doorways will take, proportionately,
considerably longer to lay than a 30 sq.m. modern rectangular room with one doorway and no
fireplace. Prefinished flooring is usually fitted very much more quickly than hand finished flooring.
In some situations the flooring contractor will not want to apply finish
to the floor until the floor has acclimatised to its new situation.
However, finishing is normally carried out 1-7 days after installation
of unfinished floorings. You can usually walk on the floor during
this waiting time unless the floor has been fine sanded in preparation
for finishing, in which case the contractor will not want you to
put dirty footmarks upon it.
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Cover doors and any ventilation ducts with plastic sheeting, properly taped
with low tack masking tape to seal off the work area.
Expect some noise during installation.
There will be noise, dust and there may be some fumes if spirit based lacquers are
being used during this process. Water based lacquers do not usually have any unpleasant
odours.
Even though the area is sealed off, sanding dust may still infiltrate other areas of
the house.
Pilot lights should be turned off if spirit or thinners based lacquers are being used.
Keep pets and children away from work area at all times.
Go over the work schedule with your contractor. Know how many days it will take until
you can walk on the floor. Do not push your contractor to complete quicker than he says is
the correct time for the job. If he is a good contractor he will want to make the best job
possible.
On completion, properly protect the floor against damage. Following trades, grit and
dirt will damage any exposed flooring – and that is a promise! Your flooring
contractor is not responsible for damage done by others. If you cannot prove conclusively
who caused the damage you may end up footing the bill for repairs yourself.
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Expectations
Things you should NOT expect from a wood floor finish !
1. Do not expect a completely flat, table top, finish. Your contractor is
making your floor by hand in your home or office. He is not working
in the ideal conditions of a factory. Each section of flooring responds
differently to the sanding process depending upon its grain type
(plain or quartered), making it virtually impossible for a completely
flat surface to be achieved on site. The joy of a hand made floor
is partly in the imperfections which are not usually present in
factory made products.
2. A dust-free finish. Whilst the finish should not be 'dusty' it is inevitable that
some air borne dust will settle on the lacquered surface. This is normally quickly worn
off by normal cleaning and foot traffic.
3. A single colour floor. Wood is a natural product. Species vary in the amount of
their colour variation. Even the plainest species vary from piece to piece. Patterned
floors show variation because of the way the light is shed when reflected from the grain
as it runs in different directions. Hence, herringbone floors appear to be made from rows
of light and dark wood.
4. A floor that will not indent. The term 'hardwood' has nothing to do with the
hardness of the wood, unfortunately. Balsa is a hardwood. Some 'softwoods' are harder than
some 'hardwoods'. Stiletto heels severely damage hardwood floors. No surface finish has
yet been invented which will entirely prevent indentation.
5. A floor that cannot be scratched. Floor finishes vary in their resistance to
scratching, but no-one has yet invented a finish that cannot be scratched. See our page on
Lacquers (this page is under construction).
6. Do not expect a floor without any open joints between the boards, or within the
parquet pieces. A new floor may have tight closed joints but it will continue to absorb
and release moisture with seasonal changes in humidity. It will expand and contract - even
if imperceptibly. Open joints will appear in the finest of solid wood floors. Joints are
more apparent in pale coloured or white finished floors. However, wide open joints greater
than 1% of the width of the widest element adjacent to the joint are not usually
acceptable - except where planned for effect.
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ON COMPLETION.:
Immediately the floor is completed, inspect the work with your contractor to ensure
that you are satisfied with the quality and finish.
Fit felt protective pads beneath chair legs. Avoid allowing pot plants to leak onto the
floor. Remember, a high quality hardwood floor is a serious investment.
Ask for a maintenance sheet, describing how you should look after your floor. Proper
maintenance will give you years of improving beauty and enjoyment !
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OTHER ISSUES:
1. Oak and Iron.:
3. Fixing methods.:
2. Underfloor Heating.:
3. Thickness of surface.:
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