Placing hempcrete - The Hempcrete Topic: Designing and Building with Hemp-lime - page 362

Any unfilled voids in the wall such as this, under the back
boxes, can be filled in afterwards.
If this happens, resist the temptation to start picking at it straight away to remove the loose
bits, otherwise there is a tendency to go on and on and end up scraping out a massive sec-
tion of the freshly cast wall, as none of it is set hard at this point! (It's a bit like picking at a
thread and unravelling the whole jumper.) Instead, it is best to do nothing for a week to ten
days, to give the surrounding areas time to harden sufficiently that the loose stuff can be
removed without taking out more than absolutely necessary. Fresh mix can then be placed
into the hole and shuttered with a small section of board with something propped against it
to hold it in place.
If there is only a small localized area of low-density hempcrete it may not actually need re-
placing, as it might eventually set firm enough to carry the plaster or render. It only needs
taking out if it's so friable that it won't hold a finish. Test this, after ten days or so, by
pushing firmly against it with the palm of your gloved hand. If it feels firm it's probably
OK; if bits of it fall out, or come away stuck to the glove when you take your hand away,
you need to scrape out the loose stuff and re-cast it.