Portland pozzalan peeeeyew
>Thanks for the reply Mike. I've done a little moreTo be optimistic I hope the addition of non
>reading and my new plan is to use 4/1 lime/cement for
>the ext scratch coat,
> so it sets up in a day and adds
>structural integrity to the house right away. I'd
>follow up with almost all lime for the brown coat with
>a little cement just to set it up faster. I want to
>use lots of lime not just for the finish but also for
>the increase in permeability. The interior would be a
>higher cement scratch coat 2/1 lime to cement followed
>by a 4/1. Hopefully this will give it a more lime-like
>finish with a reduced permeability.
>The house is two story built up post and beam with the
>beams sunk into the wall and 3' overhangs.
vapour permeable Portland cement to your vapour
permeable lime plaster will produce the result
you are looking forand that the consequences of
your action if any will be minor As you wish to
experiment with this (perhaps you think "Just a
little Portland is OK?") then could I suggest you
at least keep a record over the years? I would
think you might know whether or not you have
caused the bales to "sweat" (even a little bit)
by reducing their ability to shed EMBODIED vapour
within a few years, perhaps around ten years or
The "sweat/transpire" bale cycle should be firmly
established within ten years and you should know
if your bales are going to survive the next 150
years or so being covered with something that is
not going to let moist bales shed vapour as well
as Lime plaster would.
My personal main concern would be the issue of
crack filling but if you have no cracks then
maybe no problem?
My reasons for not using any Portland myself
remain the same however and that is my wish to
remain within a maintenance regime that is
centuries old, time tested and enjoy a building
coat that can be repaired through regenerative
application. And will also allow water vapour to
pass through it easily. I also prefer the
appearance of brilliant lime washed limestone
rather than Portlands twentieth century drab.
Not to mention the analogy of Portland mixes "get
it done real fast in one day eh?" with a deep
frozen hamburger and diet 7 Up and Lime plaster
with Quails eggs and Dom Perignon but to each
The right way is the hard way.