Following our architect suggestion, we installed solid ipe floor in our bathroom. There are two contiguous areas: one is the bathroom floor (nailed t&g), the other one is the shower floor (gaps between planks that sit on top of a sunken shower pan).

We would like to finish it so that, through years of daily showers, the two areas will stay as similar in look as possible.
We also have a preference for the original untreated matte ipe look.

boiled lindseed oil

The BLO will look good at first, but won't last or have any durability. I don't know what you would apply to wood in a shower. Maybe a marine varnish?

I would look into Sikkens deck finish. This is used for exterior decking and would need to be reapplied annually at a minimum. All sides of the wood in the shower should be treated. This will give you the lasting look you desire.

After posting I noticed the date on the original post. Heh, heh, heh. Not so timely.

Hi.
I have a project where client what's to use Ipe wood.Can you describe how did this wood permormed in the bathroom. Have you had professional hardwood floor installer do the project?Do you know what finish did he used? Thanks a lot.
Rafal