Wood apparently stained by lath?

[Stephen M]

My BIL is helping someone with a home renovation which involves gutting a

100+ year old house. The original walls were plaster on lath which has been removed. They would like to rebuild in such a way that the original structural members are visible. (I have not seen it but I assume that it must be post & beam construction). The structural members are some type of confer. It is unknown what type of wood the lath was.

The problem is that the lath apparently left a dark brown stain where it contacted the structural wood. The stain is not just superficial. it goes in at least 1/8". Pressure washing and sandblasting were attempted with no success.

What would cause this type of stain and might there be a chemical remedy?

Thanks,

Steve

[No]

Paint? Probably not what you wanted to hear. Semi transparent stain? probably better than paint but will still leave a bit of evidence.

Bleaching probably wouldn't work but you could try. oxalic acid is often used for wood bleaching.

Second google hit found this

luck

[Duane Bozarth]

Cause is probably plaster reaction. As someone else noted, almost surely it could be bleached out w/ oxalic acid, but my question would be "Why would you want to do that?" Would seem the character of 100+ years would be desirable...of course, after the previous adventures outlined above, there won't be anything left so may as well give it a go...

[Andy Dingley]

The "character" of 100+ years often looks quite different to what 100+ years looks like.

Certainly in interior design.