[Cob] lime mortar- must be softer than stone/history of use

[Charmaine Taylor]

I believe he said it lacked cement which means it must have been lime
mortar. Is this an indictment of a non cement mortar?
Is lime mortar as good or close to as good as cement mortar for
building stone walls?

_________
Lime is considered a perfect mortar for stone, granite, etc.. because
the mortar must ALWAYS be weaker than the    stone it  holds. cement
will not crack, it is too strong therefor  it will  not fail, and the
stone and other materials will crack, spall, fissure,  and fail.

  the purpose  of a soft mortar is to protect the natural materials...
water gets behind cement, allows freezing and cracking of the
stones/walls.   re pointing and repairing a softer lime mortar meant
the wall remained strong for centuries.  just a little maintenance
required.

it was our need for SPEED IN THE 1900S TO BUILD BRICK  BUILDINGS  that
caused th switch to cement mortars.

before then a mason would lay the first layer,   go all around the
building, while the lime was curing, he came back to the start and did
the next layer, this took too long..  we were a nation of  industry.

so they added SOME cement to set the  lime faster.. we went from a 10%
cement in a pure lime mortar  to a 90% cement with only 10% lime to
keep it barely workable.   so much for  modern needs.  it is
understandable, but not necessary on a small human scale of home
building or wall building.

the lime will grow stronger over the decades, and get to a   several
hundred + psi, but will never achieve 3000+ which is cement.

  the  old lime mortar with sand can be reground up and used as the
aggregate again to new fresh lime.. or just left to return to the
earth from your wall.


-- 
Ms. Charmaine  Taylor/ Taylor Publishing
Toll Free Order: 1-888-441-1632
www.dirtcheapbuilder.com   www. papercrete.com
PO Box 375, Cutten CA 95534