[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: GSBN: Lime plaster problems



I liked the Japanese approach which made fairly sharp pock marks to key
the plaster. The failed skin is all to easy with a smooth wall.

You might also find a useful article or two in the Getty biblio
www.getty.edu/conservation/publications/pdf_publications/lmpbib_alpha.pd
f

David A. Bainbridge
Associate Professor, Sustainable Management
Marshall Goldsmith School of Management
Business & Management Division
Alliant International University
10455 Pomerado Road
San Diego, CA 92131
(858) 635-4616     (858) 635 4528 fax
 WEB: marshallgoldsmith.alliant.edu
 
 
-----Original Message-----
From: GSBN [<a  target="_blank" href="mailto:GSBN@...";>mailto:GSBN@...] On Behalf Of John
Swearingen
Sent: Wednesday, September 26, 2007 11:58 AM
To: GSBN
Subject: Re: GSBN: Lime plaster problems

Andy,

It seems to me that major problems were weather related, the drying wind
and
freezing. You don't say just how smooth the earth plaster was before
lime
was applied. If it's a porous material the lime would be able to adhere
even
without scarfing.

The lime plaster needs to be removed in any case, and you could no doubt
get
some teenagers to deface the surface of the earth plaster for a small
fee.
Then try again in warm weather, or move the building south to a warmer
climate.

John

On 9/26/07, Andy Horn andy@... wrote:
>
> Dear all
>
> Dear all
> I know this is not strictly a SB question, but rather one of lime
plaster
> ...but really could do with some experienced input.
>
> I recently was involved in the building of a large 2 storey mud brick
> school
> classroom...in a rural part of the country. To help protect the walls
we
> applied an earth plaster followed by a coat of lime plaster on the
weather
> side. We used a hydrated lime and added plaster sand together with a
small
> amount of the adobe soil to the mix. We applied the plaster and as
soon as
> it had set applied a colour "fresco" wash for a gorgeous looking
finish.
> We
> also rewet the wall continuously for good curing, but were not
equipped
> with
> proper scaffolds and drop sheets to cover the walls from the sun and
wind
> ...and made do with a large sail that was precariously positioned
around
> our
> 2 scaffold towers.
>
> While applying the plaster, we ran into a number of difficulties. The
wind
> suddenly picked up and was drying the plaster out excessively quickly,
> leading to much cracking. So we had to rework the cracked surfaces to
get
> the cracks out. On the first morning after applying the plaster the
> weather
> turned at night and brought frost...2 months ahead of when it is
normally
> expected! There were sheets of ice in the water buckets that morning!
>
> A few weeks later, it turned out there were major problems with the
> plaster
> delaminating from the walls, (see below).
>
> The supervising architect wants to know what to do....and is being
advised
> to strip off the existing plaster and attach a chicken mesh around the
> structure and reapply the lime plaster. I am not keen using the
> mesh....don't think it is needed if there is no cement in the plaster.
> Also
> it can rust and will be expensive. The whole idea with the project was
to
> train the locals in simple inexpensive methods they can employ on
their
> own
> structures.
>
> If anyone has some insights to share or advice as to how we can do it
> better, I would most appreciate your inputs. Maybe we should have done
2
> coats....The base earth plaster coat was due to a miscommunication on
site
> was not provided with a proper key....and we were not sure how to
provide
> one with the earth plaster already hardened, without damaging /
impairing
> its strength. Any ideas for how best to do this....drill holes, angle
> grind,
> soften with water and saw cuts...???
> I also have pictures I can email to you directly if you want to get a
> better
> idea of the problem we are facing
>
> Your inputs would be much appreciated
>
> Kind regards
> Andy Horn
>
>
------------------------------------------------------------------------
----
> --------
>
> Hi Andy
>
> Here are some photos taken earlier today of Block B.
>
> Owen, Dave Osborn &amp; I all agree that there doesn't appear to have been
a
> proper bond between the lime plaster and the earth plaster. The
surface
> treatment of the substrate appears to be too smooth for bonding to
take
> place. The bad news is that there are large 'hollow' areas - at least
50%
> of
> the plastered surface. We all agreed that a good solution would be to
> strip
> the plaster off and nail/staple a layer chicken wire onto the
substrate
> before replastering. I guess that we should have scratched the surface
> deeper before we applied the plaster. Weather conditions could also
have
> played a role. The lime plaster layer is approximately 10mm thick and
> appears to be strong.
> Please give me your thoughts on this.
>
> Regards
>
> Steve
>
>
>
>
> No virus found in this outgoing message.
> Checked by AVG Free Edition.
> Version: 7.5.488 / Virus Database: 269.13.30/1030 - Release Date:
> 2007/09/25
> 08:02 AM
>
>
> ----
> For instructions on joining, leaving, or otherwise using the GSBN
list,
> send email to GSBN@...HELP in the SUBJECT
line.
> ----
>



--
John Swearingen
Skillful Means, Inc.
Design and Construction
www.skillful-means.com


--- StripMime Report -- processed MIME parts ---
multipart/alternative
  text/plain (text body -- kept)
  text/html
---