On 8/22/2015 8:42 PM, J Burns wrote:
On 8/22/15 5:24 AM, Don Y wrote:
On 8/21/2015 4:20 PM, J Burns wrote:

If the current damage is tolerable, you can keep it from progressing
with a
borate spray. The glycol helps it penetrate wood deeply.

Even if the wood surface is painted? I.e., does the solution permeate
the paint *or* do I have to rely on it gaining access via the "rotted"
portions?

It will kill fungus
and bugs and keep them from reappearing, as if you'd built with
pressure-treated wood.

Thanks! I think I have to open things up to see what's really going
on, there. It's a small portion -- but exactly coincides with my first
footfall when leaving the ladder. I.e., it could be that mechanical
stress is what has weakened the roof *seal* in that area (despite the
fact that no cracks or tears are visibly evident).

In preparing to repaint a shed, I sprayed exposed edges where there were signs
that rot might be starting. I don't remember how many days I waited to paint,
but the paint stuck.

OK. Did the painted surface *prior* to your adding that new coat (of paint)
show visible signs of having been sprayed? I.e., if I opt to spray it,
would I then have to paint it afterwards?

When mixing, more water means less penetration. The standard is 1:1, but the
instructions says you can use 2 parts water if the wood isn't over 2" thick. So
two coats of 1:1 should penetrate more than 2" beyond where you can spray.

So, for plywood underlayment, this is a lead pipe cinch! (?)

The glycol (ethylene or propylene, the same as antifreeze) is intended to draw
the borate into the wood. I've read that the borate won't go through paint, but
the glycol will. I've read that if you spray a painted surface with antifreeze,
it will go through the paint and give the underlying wood some protection. Not
having tried it, I don't know if it could loosen paint.

frown I think the best course of action is for me to remove that portion
of the underlayment and replace it (then paint it and repair the roof
covering).

Then, I can examine the damaged piece more thoroughly -- to see how far
the damage had progressed beyond what was visible. And, spray it
to see how the paint behaves -- as well as cut the treated board open
to see how well the stuff penetrated.

I.e., learn specifics in case I encounter something similar in the
future.

Thanks!