Floor Laying Technicalities

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. Go back to top. 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.

For more information on Floor Laying Technicalities talk to Parquet & General Flooring Co Ltd