Flooring can be laid on a plywood sub-floor or secured to timber floor battens. Ensure the sub floor is flat and free from moisture particularly on ground floor slabs. As with tile setting the layout of a floor is paramount. Locate the longest wall and lay parallel to that wall. Decide what length timber planks you will be using and establish a center line. Also establish the height of the floor to calculate the height of the transition if any to a neighbouring floor surface. The hardwood flooring should have a moisture content of between 10-15%. Remember to offset the planks so that each end joint is separated from its neighbour. Remember to leave the appropriate expansion joints no less than 8mm along the perimeter of the sidewalls.
Do not beginning installing a hardwood floor until all the wet trades have completed their work including the testing of all overhead pipe work. Floors should be flat to a tolerance of less than less than 3mm per 3m. Where this is not the case a self leveling compounded should be used. The concrete sub floor must be completely cured typically 4-6months after pouring. Moisture content to be no greater than 5% using a hygrometer. If one is not available a 300mm x 300mm sheet of clear polythene can be taped directly to the floor. If moisture forms on the underside of the polythene sheet after 24 hours the sub-floor is not ready.
Start by measuring the width of the floor (the wall to wall measurement at 90 degrees to the run of the boards. The final row of boards may need to be sawn lengthways. If laying on battens establish the direction and position of the battens and mark this carefully on the wall.
Install a moisture barrier on the top of the sub-floor using black builders plastic or asphalt or thick polythene sheeting. This should be overlapped by 8cm and sealed. Establish the longest wall. Drill pilot holes and face nail the first two rows of boards parallel to the wall and 8mm from the longest wall. Recess the nails using a nail set. Use 1 ½” finishing nails. After two rows blind nail the remaining flooring at 10” intervals along the length of each board. Use a piece of flooring and a mallet to tap the boards tight against their neighbours. Remember that the end joints in adjacent rows can not be closer together than 15cm. If you are installing planks over 15cm thick leave a crack the width of putty knife to allow for expansion and prevent cupping.
When you reach the final row, use a block and a pry bar to wedge the last boards (cut lengthways if necessary) tightly into position. Drill pilot holes and face-nail boards where a base shoe or skirting will cover, using the reference marks along the wall to locate the joists. Face nail along the batten lines. Set the nailheads below the surface using a hammer and nail set.
Where the flooring is to be laid on plywood sheeting ensure a small gap of 3mm is left between the plywood sheets as a vapour channel. The plywood sub-base should be no less than 12mm thick, with 18mm being recommended in Europe and the US Nail gun the plywood sheeting to the sub-base, mark face nails lines and follow the above procedure.
CRJ – 14 May 2010
Floors can be sanded with a drum sander or an orbital floor sander. Where possible opt for a vacuum sander as this will reduce clean-up. Although it may sound strange fine wood particles suspended in air is a potentially flammable mixture so it is advisable to tape up any electrical outlets. Smoking on site should not be allowed. Check the thickness of the boards and in particular the distance between the face of the board and the upper surface of the tongue as this will determine the depth to which sanding can take place.
Mask up the entire room removing wall hangings, rugs and curtains. Mask over AC vents and where possible avoid allowing dust from rising into high roof spaces. Remove any shoe molding but not the skirting. Check surface for protruding nails. Always sand along the length of the floor, overlapping and stepping sideways in small steps (3-4”) and overlapping backwards and forwards. Always keep the machine in motion as this will avoid gouging. Professional floor finishers recommend sanding a floor 2/3rd in one direction and 1/3rd in the opposite direction.
Work from coarse grit paper 30 gradually move through finer grits 60, 80 before finishing with fine100 grit. Use an edging sander to sand along the walls. After sanding down the floor for the first time check again for protruding nails, vacuum thoroughly and then begin the filling process. Use wood putty that matches the floor colour. Allow to dry. Repeat each process through the various grit sizes.
When sanding is complete ensure the floor is completely free of dust. Check for any flaws or imperfections. Darker stains can sometimes be removed using bleach. We recommend applying a protective sealant as soon as possible (even on the same day). This protects the floor from moisture and other problems that might cause the wood grain to rise and create a rough surface.
Applying stain can be a tricky process. Pour all the stain required into one container and mix thoroughly to assure an even application. Apply the stain using rags, brushes, or a roller. Go carefully and be sure it is penetrating to give an even color. Apply a generous coat and, after 5 to 10 minutes, vigorously, wipe with a rag to remove excess stain. The amount of time the stain is allowed to set on the floor will determine the degree of darkness. Where possible buff the floor with a professional buffer and a #2 steel wool disc and thoroughly vacuuming before the final finish coat is applied.
Keep rags handy to wipe up any excess. The pigments of the stain are in suspension, not in solution, so the stain must be stirred regularly during application.
CRJ – 14 May 2010
There are several different types of protective finishes. The most common are penetrating sealers or surface finishes, including polyurethane, varnish, and shellac. Penetrating sealers (mentioned under staining) penetrate the pores of the wood, so the finish wears as the wood wears and can be retouched with wax in heavy-traffic areas. They come tinted or clear. These penetrating sealers are often used as an undercoat with surface finishes; but be sure the two finishes are compatible before you begin. Surface finishes provide a tough, clear coating over stained or sealed wood. Polyurethane has largely replaced varnish, shellac, and lacquer. Often a heavy-traffic wax is applied over the polyurethane. Finishes come in a clear gloss finish (high gloss) and a satin finish (low gloss).
There are three main types of polyurethane floor finishes. Oil based finishes, solvent borne finishes and water borne finishes. Sometimes composites made up of oil-based and solvent borne finishes can be used. Oil based finishes require greater maintenance and may darken with age. Solvent borne finishes provide the hardest and glossiest finishes but are sometimes prone to edge bonding and thus later cracking at the joints. Water borne polyurethanes are flexible and those products containing little or no acrylic are also hard wearing. These products are not prone to edge bonding and in practice tend to dry quicker. Water borne finishes have minimal odour, do not darken but cannot provide a very high gloss finish.
Be sure that the polyurethane is well stirred before you apply it. The hardeners settle in the bottom and, if it is not well stirred, the floor will not dry evenly. Use a paint stick or install a bent coat hanger in a drill that has a variable speed. Stir at a low speed so as not to create bubbles in the polyurethane. Do not shake.
Ventilate the room well and wear a mask made for use with toxic fumes. In ventilating, however, be sure you're not creating a dust problem that will cause dust particles to settle on the wet floor. It is best to apply the finish with a lamb's wool applicator and a paint tray. A brush is used at the walls and in hard-to-reach areas. Apply the polyurethane evenly, moving the applicator in the direction of the grain.
Usually four coats are applied. You will need to sand with fine grade sandpaper such a (Number 100) between each coat after they have dried. The drying time will differ according to the humidity and temperature. Be sure you don't begin sanding until the previous coat is entirely dry, with no tacky feel. Sand with a buffer equipped using a #2 steel wool disc. This is easier than using a hand sander. Hard-to-reach areas should be sanded by hand. Vacuum after each sanding, and then go over the floor with a damp mop to remove all the dust. The second coat can be applied across the grain. The final coat does not need buffing.
CRJ – 14 May 2010