How to Sand and Polish Timber Floor

 

Preparation

The floor to be sanded must be free

from all furniture. If the room has built in

cupboards or wardrobes, do these as

well, otherwise they will be different to

the main part of the floor and may look

odd. In the scheme of things, not doing

this won’t save much time or material

anyway.

If you have removed carpet from

some of the floor, ensure the carpet

ripple bar sits just inside the room.

That is, if the door is closed, the carpet

cannot be seen. This gives the hallway

continuity. If possible remove curtains.

If not, wrap in plastic sheeting and raise

well above floor level. Remove ducted

heating covers and stuff ducts with

paper (below floor level). Ensure that

metal duct casings are below floor level,

if not they will damage the sanding

paper when running over the edges.

Seal off open doorways with drop

sheets. Check the type of masking tape

as some may adhere to painted surfaces.

Step 1. Punching and

puttying

If your floor is new, it will most

likely be secret nailed. The secret

nailing process typically involves fixing

the boards at each edge with the nails

driven at a 45 degree angle. As the

name suggests, the nail holes are not

visible when the floor is completed. The

boards are also glued to the substrate for

added strength.

If it is an older floor and the nails are

visible then sinking them down with a

nail punch and hammer to a depth of

approximately 4mm will be necessary.

Any nails not sunk will damage the

sanding paper and the machine drum.

Vacuum to remove any dust particles

in the nail holes and between boards. To

ensure a good match with your timber,

choose a putty to suit your flooring,

or putty can be mixed to achieve the

colour required. Do not use an epoxy

type of putty if you will be using natural

penetrating oils such as the Livos oils

- Timbermate is a good match Putty.

larger holes slightly overfull as putty may

sink lower than floor level if the hole

is not filled properly. If you have wide

gaps in between your floor boards, it is

best to get used to them. By puttying

along the length of them, with time and

floor movement these have a tendency

to crack and fall out and will cause an

  

unsightly appearance, more so than

having a nice even gap.

Wait till the putty is completely dry

before continuing to sand. When oiling,

no cutting back is necessary so puttying

must be done in the initial stages.

If the flooring contains natural

features such as black gum veins, putty

these in black while the nail holes are

puttied as close as possible to the colour

of the timber.

Step 2. Coarse sanding

(cross sanding)

This first step of sanding is to

provide a level and evenly sanded, bare

floor free from any coatings. For new

floors, this first step is used to cut the

boards level by taking out any ridges or

high points. With old floors, it removes

the old varnish or paint. If your flooring

has a heavy varnish finish or bitumen

paint, you may need to start the sanding

with a 24 grit belt otherwise 40 or 60

grit will be sufficient.

Start at a point 45 degrees to the

floorboards and from which will allow

the longest and widest path through

the room. When starting the machine

ensure that the drum is not touching

the boards. Move forward slowly, easing

the drum onto the boards. Lowering

the drum quickly may leave grooves or

‘chatter marks’ that may be difficult to

sand out. Attempt to sand as close to

the wall as possible. Maintain an even

pressure and slowly raise the drum

as you reach the extremity of the line

of sanding. Begin to walk backwards,

pulling the machine, easing the drum

to the floor. Continue back to where

you started from.

When the original starting point is

reached gradually raise the drum from

the floor. Move the machine to the right

or left of this sanded path ensuring an

overlap of 50 to100 mm onto the first

cut path. Check and replace clogged

belts as required.

Continue in this manner until you

have reached the limit of accessibility.

Go back to the original starting point

and work away from the first cut. That

means if you went to the left away from

centre, then work toward the right side

of the room. Much depends though on

the room layout.

During this process the need for

repair work may become evident. Once

the rough sanding has taken place,

borer or termite damage may have

been exposed. If repairs are required,

do those before you continue with the

sanding.

If the floor is in a sad state the

second cut can be made in the same

manner as above but working at 90

degrees to the first cut. Only do this if

absolutely necessary and ensure that the

boards are thick enough.

The third cut (or as in most cases

the second cut) is carried out in the

direction of the boards. As the boards

are now mainly level and most of the

old coatings removed this cut may be

done with a higher grit paper than the

diagonal cuts.

Once a new path has been cut,

move to the left or right and ensure

an overlap of 50 to 100 mm. Continue

this process across the room. When

the full width of the room is sanded,

turn around and sand the other side of

room.

Step 3. Edging

Now it is time to use the edge sander.

The perimeter needs to be sanded level

and blended into the body of the floor.

Overlap a distance of some 100 to 150

mm. Care should be taken that the

machine is held level so that the edger

does not dig groves into the boards.

Repeat the sanding and edging gradually

working up to a finer grit. Grades of

paper used on the edging machine

are the same as those used on the belt

sander; if you started sanding with a 40

grit and finished with 120 grit then use

the same sanding grits for the edging.

If you think you can take shortcuts by

starting off sanding with 40 grit and

then jumping to 100 grit, you will have

a badly scratched floor and will need

more time and materials to rectify the

scratches left by the 40 grit papers.

Never use an edge sander in the

middle area of the floor. It could leave

swirl marks or deep cuts that may be

very difficult to sand out.

Middle sanding

The second sanding removes the

scratches left from the previous sanding

and creates a finer surface. Repeat the

same process, but this time use a finer

grit than previously. This time, only

move the machine along the length of

the boards; no cross cutting is necessary.

Again, use the edge sander with the

same grit paper that you have just used

to do the main part of the floor.

 

The final sand

The final sand uses a finer grade of

paper – once again reducing the depth

of the scratching and prepares the floor

for the coating system.

Vacuum the floor, not forgetting the

window sills and door frames.

Corners

For areas that the edge sander

cannot reach use a triangle sander

and sand close into the corners and

around the door frames finishing off

with at least 120 grit sandpapers.

Ensure that all sanding marks have

been removed.

If no machine is at hand, use a sharp

paint scraper. The scraping action

should always be in the direction of the

grain. Then sand by hand along the

grain of the timber to a fine finish.

If you do not have a paint scraper

and your corners are heavily varnished

or have paint spills, use a sharp chisel to

gently remove the varnish or paint, then

sand by hand again along the grain of

the timber.

Buffing

If using a synthetic varnish, then this

step may not be necessary. If, however,

you intend to use natural oils, it is

highly recommended. This will achieve

a finer finish and a surface that will not

require re-sanding when rejuvenation is

necessary.

Fit the buffer with a white pad and

a 100 grit screen back (sanding screen

disc). If you have never used a buffer/

rotary sander previously, start in the

centre of the room and work it towards

the wall slowly. Never let it sit in one

place and over sand a spot.

Work around the perimeter of

the room. Once back to the starting

point move the buffer backwards and

forwards across the grain. Overlap

each pass generously and sand the

entire floor. Move slowly and get close

to the edges. Pay particular attention

to the area where the belt sander and

  

edger overlapped. One side of the

screen back should be enough for a

20m2 room. Turn the screen back

upside down and repeat the procedure,

however this time working along the

grain of the timber.

Repeat the buffing with a 150 screen

back in the same manner as above.

Cleaning

Vacuum thoroughly not forgetting

window sills, door frames etc. It is

recommended that floors be vacuumed

in the same direction as the floorboards.

Do not drag the vacuum cleaner along

the freshly sanded boards as marks may

be left.

The floor should now be scratch free.

If using natural penetrating oils these

will enhance the colour and structure

of the timber but will also highlight any

imperfections in the sanding, even more

so if using stains.

If using a varnish, then it is

imperative to remove all dust and grit

from the floor and surrounding areas. If

not, the dust will adhere to the freshly

lacquered floor and give a gritty look.

Finishing the floor

Apply the floor finish you have chosen

once sanding is completed. Do not allow

others on the floor as they may have

contaminants on their shoes that will

only show up once the floor is coated.

Follow the manufacturer’s instructions

and wear protective equipment if

necessary to guard against strong vapours.

It may be necessary to arrange alternative

accommodation for some days.

Sanding floors is strenuous to say

the least and you need to weigh up the

cost of and accessibility of machines and

materials and the time involved. It may

be more cost effective to have it done

professionally and have someone else

accountable for the sanding and finishing.

If you do sand and treat your floor,

the sense of achievement will far exceed

the aches and pains.