How To Sand & Seal Floorboards
Jan 25, 2010 DIY tips, how to, sanding wood floors, sealing wood floors, staining wood floors, wood flooring
We have been sanding and sealing, staining and restoring floors for over 10 years, although we would recommend that you use a professional to sand and seal your floor, you can do it yourself, if you follow this simple guide.
Click here to: Rent a floor sander in Farnborough.
Preparation
It is the key to every job we do, if your prep is bad the finished job will be terrible, if prep is excellent the finished job will be outstanding.
The whole point of sanding and sealing is that you should be able to recreate a factory applied finish on site (at least that is what we aim to do).
Firstly you need to prepare your floor for sanding, you need to remove all nails from any gripper rods that were in-situe before, also any bits of carpet underlay that have become stuck to the floor. Once you have fully cleaned the area you need to check for any loose boards, if you find any lift them up fully to check for pipes underneath, then, using cut nails 1 ½ to 2 inch, nail them back down carefully. Then set all the nails in by at least 3mm using a centre punch and hammer, this will increase the life of the sanding belt, and limit and damage to the drum.
Sanding
You are now ready to start sanding; you should start with a 36 grit belt or 40 Grit (depending on the state of the boards). Sand in the direction of the boards, never work diagonally or across them as this will put scores marks in that will take forever to remove. If you are using a Hiretech HT8 then you will need to be very careful, as these machines are really light and they tend to jump and skip over the boards rather than sand them. When sanding never leave the machine in one place for more than 2 seconds as it will create burn marks in the board that are impossible to remove. Rather keep the sander moving at all times and let the roller gently coast on the floor.
Bona FlexiDrum
We use (and hire out) a Bona Flexidrum, this has a continuous belt on a rubber drum, the belt just slides on, no need for metal bars and screws as on the HT8. It weighs around 60kg (very heavy) and has a 2.2kw motor, it is incredibly fast at removing material and is 98% dust free; it always leaves a beautiful finish.
The 36 or 40 grit should be used until all of the boards are sanded back to bare wood, if the boards are particularly curved you could use a small sander to get the very edges of the boards cleaned up. Once you are back to bare wood you can start working through the other grades, don’t be tempted to skip grades you must work through them all – 60, 80, 100, 120 grit. Once you have sanded to 100 grit you should start sanding the edges, again keep the sander moving at all times, start with the most coarse disc and work to the finest (80 grit). After the edges are done, do the corners and around any pipes with a detail sander 40 to 60 grit (no need to go any finer it’s a very small area). After all this is done its time to do the final pass with the 120 grit belt, before running a random orbital sander around the edges (60 working to 100 grit). The final pass should be no more than twice in each direction, you’re not trying to remove material but just giving a final light sand. With this part done now your onto the final stage (at last)…go around the whole room with a random orbital sander, sand out any score marks or swirls that are in the boards, start at 60 grit, then 80 and finish with 100 or 120.
I know this all sounds very long winded, but trust me if you put the preparation in you will be rewarded when it comes to applying the finish.
Staining
If you are going to stain the floor you obviously need to do it before the seal is applied. We recommend the use of a solvent based stain that can be lacquered over. We use Bona Décor. We apply this stain with a rag in a circular motion, working the stain into the boards; you must make sure that all the stain is fully rubbed in with no ‘wet looking patches’. Once you have done this the stain needs to dry for 24-48hrs before applying your primer coat.
Most stains that are oil based cannot be lacquered over; instead a top coat of oil is applied after the stain. We have in the past used spirit based stains; however these can be notoriously difficult to apply evenly, especially on woods that are porous like beech. If you are using a spirit based stain you have to work very quickly and always keep a ‘wet edge’, on porous woods the stain should be diluted with white spirit so that it can be applied more evenly.
Sealing
Before Sanding
You’re now ready to seal the floor, so firstly fully vacuum it off ensuring that there is no dust of any kind on the floor. We always recommend the use of a base coat primer such as Bona Prime Intense or Prime Classic. A primer stops any side bonding, this is when the floor expands and rather than each block moving individually, they more as a section creating a shear line in the pattern (herringbone block). A primer enables the floor to move under the lacquer (the primer has elastic type qualities) avoiding any cracks from side bonding. This is obviously very important on any parquet or herringbone floors, not so important for floor boards but it is still good practice, as it is an extra layer of protection and aids adhesion of the top coat.
Firstly shake the bottle of lacquer well for one minute, then using the filter provided, decant it into your roller tray. Brush all the edges of the floor first using a fine bristled paint brush, making sure to cover all corners and come about 4 inches of the wall. There is no need to wait for this to dry you can carry straight on with covering the rest of the floor.
We apply the lacquer with a roller, again from Bona, don’t be tempted to use a paint roller, the lacquer roller that Bona make are guaranteed to give an orange peel free finish without dropping any pile.
When you have covered the entire floor, and checked that you have not over applied in any areas (this can be seen by a blue looking film on the surface) leave it to dry for 2 to 3 hours. You have a choice now, you can either nib the lacquer back with a buffing machine or not, if you don’t you will get a rougher grippier finish than if you nibbed it back.
After Sanding & Sealing
If you go down the buffing route then you need to use the buffer on the slowest speed with a maroon pad and a scrad wing (a small sanding sheet that sticks to the maroon pad). Work over the floor quickly keeping the sander moving all the time, if you stay in one place to long you will rip through the primer.
After this, vacuum the floor again to ensures a dust free surface, then apply the lacquer in exactly the same way as you applied the primer, leave to dry for 3-4 hours then repeat for the final coat. The floor will need two top coats, making three in total, if you buffed the primer the first time round then you need to do the same with the first coat of lacquer. Do not buff the top coat; it should be pretty smooth if you buffed the two previous coats.
So that’s it! All done!
NB – Make sure you put felt pads on any furniture in the room as this will stop any scratches when moving furniture about.
Tags: Bona, Flexidrum, sanding, sealing, staining, wood floors
Traditional Secret-Nail Fixing of Wood Floors
Jun 10, 2009 DIY tips, bonding, how to, wood flooring
Solid tongued and grooved strip and plank flooring may be installed by secret-nail fixing to suitable wood-based sub-floors such as floorboards, flooring grade chipboard, plywood, or OSB.
In most cases existing decorative hardwood floorcoverings should be removed before the installation of new hardwood flooring.
Environmental Conditions
- All wet trades must be thoroughly dry before flooring materials are delivered to site.
- Maintain suitable ambient humidity 40 to 60% RH. (Monitor with a hygrometer)
- If necessary employ a domestic humidifier or dehumidifier to maintain suitable humidity.
- Ambient temperature to be 18 to 22 Celsius during acclimatisation and installation.
Basic Requirements of the Sub-floor
- Wooden sub-floors must not be installed as a floating floor, but be securely fixed (e.g. floorboards to joist).
- Ensure all sub-floors are sound, free from decay, and of load-bearing strength.
- Wood based sub-floor materials must not be more than 2% higher in moisture content than the new wood flooring materials being installed.
Tip
- Flooring must not be exposed to artificial heat sources from the sub-floor. Hot water pipes beneath suspended wood floors can cause excess heat and should be thoroughly insulated. Floor temperature must not exceed 24 Celsius.
Evenness of sub-floor
- All wood based sub-floors must be even to within 2mm over any 2 lineal meter area.
- In order to achieve the necessary degree of evenness, traditional softwood floor boarded sub-floors typically require a WBP plywood covering to be securely fastened (preferably by screwing) to the floorboards before secret-nail fixing new wood flooring. (Plywood must also be of suitable moisture conditions. See ‘Basic Requirements of the sub-floor’ above.
- It is recommended that flooring grade chipboard, OSB & old floorboards are first covered with WBP plywood which is securely fastened to the sub-floor before secret-nail fixing new wood flooring, as this will hold nails well and help avoid squeaking.
Suspended wood based sub-floors at ‘ground level’
- Voids beneath suspended wood based sub-floor on ground level must be well ventilated to avoid high humidity in the sub-floor void.
- First lay a building paper moisture barrier (e.g. Sisalkraft Moistop), over the existing sub-floor overlapping joins by 100mm and taping with a waterproof tape.
- Then install a WBP ply layer, securely fixing through the building paper to the sub-floor.
Secret-Nail Fixing
- When fixing flooring solely by secret-nailing, we recommend that a building paper moisture barrier (e.g. Sisalkraft Moist Stop), is laid over the existing sub-floor overlapping joins by 100mm and taping with a waterproof tape.
- Boards of 150mm or wider may be secured with adhesive in addition to secret nail fixing.
- When using the combination of secret-nailing and adhesive, a moisture barrier building paper is first laid over the existing wood based sub-floor, followed by WBP ply. The WBP ply is securely fixed through the building paper into the wood based sub-floor. Hardwood flooring is then bonded to – and nailed through the ply base into the existing wood based sub-floor.
- Secret-nail fixing is achieved using a purpose made floor nailer (e.g. Portanailer, Primatech etc) which are used with purpose made serrated galvanised floor nails of varying length depending on the thickness of flooring being installed. (18-20mm flooring thickness = 50mm nail).
- Tongue and groove flooring is secret-nailed (also called ‘blind nailed’) fixed through the tongue at approx 45 degrees into the sub-floor at intervals of 200 to 250mm.
- Nails are placed 40 to 60mm to each end of each boards, with not less than two nail fixings per board.
- In addition to secret-nailing on the tongue side, starting rows one and two are face nailed or can alternatively bonded to sub-floor to secure the groove side that is not linked into an adjoining tongue
- If starting from a centre line using biscuit tongues, the two centre boards may be face nailed or preferably bonded to the sub-floor using a flexible adhesive.
Provision for expansion
- As a guide only allow a minimum 15mm expansion wherever the floor meets obstacles including perimeters walls, structural supports, hearths etc.
- Create additional expansion breaks in doorways using suitable profiles such as T-section thresholds / transition strips.
- Create additional expansion breaks in large floors.
- Where possible install flooring so that planks, strips run parallel to the longest walls, so the direction of greatest potential expansion (i.e. across the grain) does not coincide with the direction of greatest dimension, esp. in large floors.
- The precise combined provision for expansion must be judged by the installer taking into account environmental humidity, moisture content of wood at time of installation, timber specie and size of the floor.
For more information see our wood flooring site.
Tags: adhesives, Bona, bonding, DIY guide, secret nailing, Sika, solid wood flooring, underlays
Bonding to Wood based Sub-floors
Jun 10, 2009 DIY tips, bonding, how to, wood flooring
Wood-based sub-floors are materials such as floorboards, flooring grade chipboard, plywood, or OSB.
Existing hardwood floor coverings should be removed before installation of new hardwood floors.
Environmental Conditions
- All wet trades must be thoroughly dry before flooring materials are delivered to site.
- Maintain suitable ambient humidity 40 to 60% RH. (Monitor with a hygrometer)
- If necessary employ a domestic humidifier / dehumidifier to maintain suitable conditions.
Moisture condition of Wood based sub-floors
- Ensure that wood based sub-floor materials are not > 2% higher in moisture than the new wood flooring materials being installed.
Suspended wood based sub-floors at ground level
- Voids beneath suspended wood based sub-floor on ground level must be well ventilated to avoid high humidity in the sub-floor void.
- First lay a building paper moisture barrier (e.g. Sisalkraft Moistop), over the existing sub-floor overlapping joins by 100mm and taping with a waterproof tape.
- Then install a WBP ply layer, securely fixing through the building paper to the sub-floor.
Soundness of sub-floors
- Ensure all sub-floors are sound, of load-bearing strength and free from contaminants that may impede adhesion. (Note: If sub-floors are contaminated or affected by adhesive residues seek further advice).
Evenness of sub-floor
- In order to achieve satisfactory contact between wood flooring and adhesive, sub-floors must be even to within 2mm over any 2 lineal meter area.
- Floor boarded sub-floors typically require a WBP plywood covering to be securely fastened to the floorboards before adhesive fixing new wood flooring.
- It is recommended that flooring grade chipboard, OSB & old floorboards are first covered with WBP plywood which is securely fastened to the sub-floor before adhesive fixing new wood flooring to protect against surface contaminants that may impede adhesion.
Adhesive bonding of wood flooring to wood based sub-floor
- Use a purpose made, permanently flexible adhesive such as 1-part polyurethane, when adhesive fixing.
- Always use the trowel type recommended by the adhesive manufacturer for the type of flooring being installed (e.g. solid plank, strip, woodblock, engineered plank etc).
- Replace worn trowels.
- Ensure full contact between the underside of the flooring element and adhesive.
- Any adhesive that that comes into contact with the face of the boards must be cleaned off whilst wet, as residues are not removable when cured.
Provision for expansion
- As a guide only allow a minimum 15mm expansion wherever the floor meets obstacles including perimeters walls, structural supports, hearths etc.
- Create additional expansion breaks in doorways using suitable profiles such as T-section thresholds or transition strips.
- Create additional expansion breaks in large floors.
- Where possible install flooring so that planks, strips run parallel to the longest walls, so the direction of greatest potential expansion (i.e. across the grain) does not coincide with the direction of greatest dimension, esp. in large floors.
- The precise combined provision for expansion must be judged by the installer taking into account environmental humidity, moisture content of wood at time of installation, timber specie and size of the floor.
You can contact us for more information at www.floorcraft.uk.com or call us on 01252 372227/07970 491384 ask for Gavin Winder (we are based in Farnborough, Hampshire, UK and stock all of the above mentioned wood flooring adhesives, latex, underlays etc).
Tags: adhesives, Bona, bonding, DIY guide, Duralay, latex, Sika, underlays, wood flooring
How to Bond a Wood Floor
Jun 10, 2009 DIY tips, bonding, how to, wood flooring
Both solid & engineered wood flooring can be bonded to a variety of sub-floors using purpose made adhesives, creating a traditional solid feel underfoot.
Environmental Conditions
- All wet trades must be thoroughly dry before flooring materials are delivered to site.
- Maintain suitable ambient humidity 40 to 60% RH. (Monitor with a hygrometer)
- If necessary employ a domestic humidifier / dehumidifier to maintain suitable conditions.
Moisture condition of mineral based sub-floors
- Ensure that screeds, concrete, etc are less than 60% Relative humidity before installation commences.
- Employ a suitable primer moisture barrier if necessary, we recommend Bona R410 or Sika MB.
- At ground floor level and below, wood flooring must be protected from ground water by an integral DPM.
We recommend Duralay Excel or Duralay Silent Gold or in the case of basements by tanking, however due to moisture levels normally being particularly high in basements we would not recommend the use of solid wood flooring.
Soundness of sub-floors
- Ensure all sub-floors are sound, of load-bearing strength and free from contaminants that may impede adhesion. (Note: If sub-floors are contaminated or affected by adhesive residues seek further advice).
- Check that the sub-floor has a satisfactory cohesive strength before adhering wood flooring. i.e that it is not breaking up or loose
- Avoid accelerated drying of new concrete/screeds as this may lead to poor cohesive strength and may also cause the screed/slab to slump
Evenness of sub-floor
- In order to achieve satisfactory contact between wood flooring and adhesive, sub-floors must be even to within 2mm over any 2 lineal meter area.
- If levelling is required above a suitable primer moisture barrier, apply a purpose-made fine graded aggregate over the second coat of wet primer, allow to cure then vacuum off all loose aggregate; (This will aid adhesion between primer and levelling compound). Then use ‘rapid dry formulae’ water-mix (i.e. instead of latex mix) levelling compound, as these are typically stronger and develop strength quicker, we Recommend Dunlop or Aritex Yellow bag and bottle
- Ensure that levelling compounds are fully cured and thoroughly dried in favourable drying conditions before installation commences
Adhesive bonding of wood flooring to sub-floor
- Use a purpose made, permanently flexible adhesive such as 1-part polyurethane, when adhesive fixing, we recommend Bona R850 or Sika T54
- Apply adhesive to the sub-floor not the wood flooring or the tongue and groove.
- Always use the trowel type recommended by the adhesive manufacturer for the type of flooring being installed (e.g. solid plank, strip, woodblock, engineered plank etc).
- Replace worn trowels.
- Ensure full contact between the underside of the flooring element and adhesive.
- Any adhesive that that comes into contact with the face of the boards must be cleaned off whilst wet, as residues are not removable when cured.
IMPORTANT NOTE
Always check the mutual compatibility of moisture barriers, primers, aggregates, levelling compounds and adhesives before installation. Refer to instructions for use for each product.
Provision for expansion
- As a guide only allow a minimum 10mm expansion wherever the floor meets obstacles including perimeters walls, structural supports, hearths etc.
- Create additional expansion breaks in doorways using suitable profiles such as T-section thresholds or transition strips.
- Create additional expansion breaks in large floors.
- Where possible install flooring so that planks, strips run parallel to the longest walls, so the direction of greatest potential expansion (i.e. across the grain) does not coincide with the direction of greatest dimension, esp. in large floors.
- The precise combined provision for expansion must be judged by the installer taking into account environmental humidity, moisture content of wood at time of installation, timber specie and size of the floor.
Tip
- Flooring must not be exposed to artificial heat sources from the sub-floor. Hot water pipes within screeds can cause excess heat and must be thoroughly insulated. Floor temperatures must not exceed 24 Celsius.
You can contact us for more information at www.floorcraft.uk.com or call us on 01252 372227/07970 491384 ask for Gavin Winder (we are based in Farnborough and stock all of the above mentioned adhesives, latex, underlays etc).
Tags: adhesives, Bona, bonding, concrete, DIY, Duralay, flooring, glues, latex, screeds, Sika, underlays, wood
