Revarnishing timber floor.

aujopimur

I have semi solid oak floor, the original varnish has worn away.
It has a few black spots from where the dog took a pi$$ a few times.
What's the best treatment for the black bits, and what's best to revarnish it with after I've sanded it back?.

the_pen_turner

the hardest part is going to be the black parts. that is where the amonia in the urine has darked the colour of the oak . it has reacted with the tanins in the oak. its a nice finish on fine furniture (no dog pee involved thow).
its hard to tell haw deep it has went without sanding it. it might be too deep to remove .

you might be better staining a darker colour to hide the darkness.


on the flip side it might be really easy to remove of the varnosh has sealed the pores in the oak.
get soe 80 grit sand paper and sand with the drain on the dark areas to see if the darkness is really thin or thick.

sanding the floor will need a big industrial sander hired out and a days sanding depending on the size.

Dublin City Handyman

Unfortunately I don't think your going to get rid of the black pee marks.. I have tried before.

aujopimur

Any suggestions on what to use for recoating?.

tabby aspreme

aujopimur wrote: »

Any suggestions on what to use for recoating?.

Three choices , oil or water based polyurethane, or cellulose lacquer .
Oil based polyurethane probably the hardest wearing will need 24 hrs between coats and will darken the wood slightly, water based polyurethane 3 hrs between coats won't darken the wood not as hard wearing ,both easy too apply, can be brushed or rolled on, cellulose based lacquer 1 hour between coats , won't darken the wood difficult to apply due to fast drying and fumes, harder wearing than water based , there are also some wax and pure oil based finishes but they are more suitable for solid wood and will require ongoing maintenance.

dathi

Dublin City Handyman wrote: »

Unfortunately I don't think your going to get rid of the black pee marks.. I have tried before.

http://www.lenehans.ie/oxalic-acid-500g.html
oxalic acid will take most of the stain out be careful with it as asthe dust is nasty and extremely bad for your health

allycavs

I would use steel wool before sanding paper. you be surprised how easily you get down into wood. sometimes sandpaper takes too much away on softer parts and on heavier darker parts no amount of sanding will do if the amonia is ingrained. When you go to varnish then you will have patches that are darker. I found the wire  wool will give you a more even finish in the end. i used ronseal diamond floor varnish (with a walnut stain in varnish). its not down long enough to say if it will be long lasting finish but i was happy with finish (except for parts where i used sandpaper as opposed to wire wool).

tabby aspreme

A word of caution if using wire wool on oak, small fragments of the steel remain in the wood pores, so do not use a water based varnish as this will cause the tannin in the oak to react with the steel resulting in dark blue / black spots forming in the wood pores