Thanks to all who made comments on my
problem with green algae growing on the
outside of my vinyl siding and that lower
pressure 'washers' may do the job but
maybe at a slower rate.

I will look into 'siding cleaning' agents
and maybe try them, too. We've had a variety
of experience with fungus (black, rather
than green, smudgyness and dots) and
cleaning that with soap/bleach by hand (not
fun at all).

The warning about water being injected
behind the siding is a valid concern
and I'll have to think about this. I do
know that it is not uncommon for people
to power wash their homes at some interval
and that unwanted side effect is certainly
a possibility. I was present during one
power wash of someone else's house and
water did get injected behind roof flashing
and started drippingfrom an interior room
ceiling.

In the house we owned before the present,
we had the exterior power-washed before
selling the house AND also after the power
wash I replaced some of the siding (cedar)
because of unsightly pre-existing cracks
and/or warps (the moisture barrier was,
believe it or not, roofing felt) and I
noticed no moisture residue or short-term
rot (house & siding were about 20 years old)
and I mention this as an FYI.


Art Sowers
(email is invalid)

"straydog" wrote ' in part ' in message
...



..............(the moisture barrier was,
believe it or not, roofing felt) and I
noticed no moisture residue or short-term
rot (house & siding were about 20 years old)
and I mention this as an FYI.

When you say 'Moisture barrier' are you referring to the "roofing felt"
being immediately under the exterior clapboard cladding/finish?
If so that would not be a moisture barrier; those are installed on the warm
or inner side of a wall or ceiling, to prevent warm (and therefore moisture
laden) house air from seeping out and condensing inside the walls and
insulation.
What should have been used under house siding AIUI, back before today's
'Type style' products, would have been some kind of permeable barrier which
would have allowed moisture that did get within the wall to have 'breathed
out'. Maybe your roofing felt would have met that requirement?
I have used 'Building paper' in such a situation and plastic sheeting
internally on the walls etc. as the 'Vapour Barrier'.
Curious.