Black gunk on top of my floor boards

[BigCal]

Hi everyone,

I have some sort of black substance on top of some of my floor boards (i am unsure how large the area of it is as alot of tiles are still down...) I think its been used to level the floor, the floor used to have yellow tongue next to cypress boards, the yellow tongue had a lot of the black gunk on top of it the cypress not quite so thick...

Anyone have any ideas on what it is and how best to get it off? It's gind of softish, like its not hard and brittle... i think sanding it, its going to clog sand paper real quick... but is there any other option? i could scrape it with a chisel but I dont want to damage the tops of the boards...

Cheers

[Ashore]

will help alot

[BigCal]

Ok, here's a section of it... just been doing some reading which sparked my memory that apparently there was slate in the house once upon a time and this is quite possibly tar from under the slate? other sections of tiles i have removed tho don't have any of it... which still makes me think it was just used to level the floor...

In pic left is the old tiles that are going, middle is the black stuff and right is the recycled board i have just laid where the yellow tongue was...

[BigCal]

I rubbed a bit of metho on with a kitchen cloth and this removed quite a bit, I reckon metho with a scourer type pad would get most of it off... my question now is will metho affect the look of the timber if used sparingly? I read metho can be used to make timber look more "baltic"??

[Tools]

Looks like the black japan they used to use around the perimeter of a room with carpet in the middle. It will sand off easily.

Tools

[Tools]

Having re-read your post, maybe it is resaflex or similar flexible adhesive.

Tools

[kman-oz]

Looks a lot like Lino adhesive. My floor had this all over the kitchen area. I removed most of it with metho and a scraper, then sanded the surface.

[HappyHammer]

does it ball up when you rub it, if so it could be a lino adhesive or the rubber backing of something previously stuck to the boards. Could it be sap that leached from the boards when laid?

HH.

[BigCal]

Rubbing it with fingers/hands does nothing the stuff is stuck to well, scraping it with a chisel gets it moving... or rubbing it with a cloth with metho on it...