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GSBN: Digest for 9/26/07



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---------------------------------------------------------------------


-> GSBN: Lime plaster problems
     by "Andy Horn" andy@...
-> Re: GSBN: Lime plaster problems
     by jswearingen@...
-> Re: GSBN: Lime plaster problems
     by David Eisenberg strawnet@...
-> Re: Lime plaster problems
     by "moehlmann" moehlmann@...
-> RE: GSBN: Lime plaster problems
     by "David A Bainbridge" bainbrid@...
-> Re: GSBN:Re: Lime plaster problems
     by john@...
-> Re: GSBN: Lime plaster problems
     by jeff@...


----------------------------------------------------------------------

Date: 26 Sep 2007 12:50:06 -0500
From: "Andy Horn" andy@...
Subject: GSBN: Lime plaster problems

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 & 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




----------------------------------------------------------------------

Date: 26 Sep 2007 14:06:51 -0500
From: jswearingen@...
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 & 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
>
>

>



- --
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
- ---


----------------------------------------------------------------------

Date: 26 Sep 2007 14:44:39 -0500
From: David Eisenberg strawnet@...
Subject: Re: GSBN: Lime plaster problems

Actually, John, Andy in Cape Town, South Africa would need to move the
project north to a warmer climate...

Andy, I wish I had more direct experience to be able to offer you some
advice or guidance, but I know that there are many people on this list
who have more of that I do and hope they chime in with it soon. I wish
you good luck with the resolution and applaud your willingness to share
the experience so that hopefully we can all learn and benefit from it.

Warmest regards,

David Eisenberg
www.dcat.net

- -----Original Message-----
From: John Swearingen john.skillfulmeans@...
To: GSBN GSBN@...
Sent: Wed, 26 Sep 2007 11:57 am
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 & 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


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- ----







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----------------------------------------------------------------------

Date: 26 Sep 2007 15:25:07 -0500
From: "moehlmann" moehlmann@...
Subject: Re: Lime plaster problems

Hi Andy, dear all,

seems that your building is not protected at the moment and because of the
cold its not the time to repeat any of the rendering options.
You might choose a temporary protection for the winter or directly change
the outer design and add a woodden cladding, something I did when
winterstorms blew into a not yet and as such poorly protecting lime plaster
(takes a year to complety protect with 3 layers of limeplaster: 1. layer
airlime/hydraulic lime, 2nd and 3rd layer airlime) and frost which let the
3rd layer fall down....
Pictures of the cladded house www.ecovacancesbretagne.com

Best wishes,
Martin Oehlmann

- ----- Original Message -----
From: "Andy Horn" andy@...
To: "'GSBN'" GSBN@...
Sent: Wednesday, September 26, 2007 8:37 PM
Subject: GSBN: Lime plaster problems


> 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
>
>

>
>




----------------------------------------------------------------------

Date: 26 Sep 2007 15:50:47 -0500
From: "David A Bainbridge" bainbrid@...
Subject: 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 &amp; 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 ---
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  text/plain (text body -- kept)
  text/html
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For instructions on joining, leaving, or otherwise using the GSBN list,
send email to GSBN@...HELP in the SUBJECT line.

- ----



----------------------------------------------------------------------

Date: 26 Sep 2007 16:59:45 -0500
From: john@...
Subject: Re: GSBN:Re: Lime plaster problems

G ' day Andy

My two rands worth mate.

You will need to remove the lime coat and scratch up the earth as
others have said.

I would then apply a mix of earth/lime/sand and chaff or chopped straw.

All depends on the clay content of your earth but I would look at
something like this 3 parts soil 2 parts lime 3 parts sand 1 part
chaff.  I use buckets for this mix.  It works well and binds well with
the earthen render.  Then if you want you can apply a finish coat of
lime render however I have not found that necessary in most cases
except for look.

You can see a house we renedered with earth, then
earth/lime/sand/chaff, then lime/sand, here:

<a  target="_blank" href="http://glassford.com.au/Jumbo.htm";>http://glassford.com.au/Jumbo.htm</a>

No delamination no cracks and it is nearly 6 years since we finished there.

Was in Cape Town a few weeks ago but did not have time to see much it
was a Rotary trip with Hout Bay.  We will be back next year for an
extended visit, see you then.

Kind regards
The Straw Wolf
Huff 'n' Puff Constructions
<a  target="_blank" href="http://www.glassford.com.au/";>http://www.glassford.com.au/</a>

61 2 6927 6027

Mount Kilimanjaro Climb 28/8/07
<a  target="_blank" href="http://www.coolamonrotary.com/kili/";>http://www.coolamonrotary.com/kili/</a>


----------------------------------------------------------------------

Date: 26 Sep 2007 17:29:30 -0500
From: jeff@...
Subject: Re: GSBN: Lime plaster problems

Andy,

We have dealt with freezing temps with lime plaster with very little
consequence.  My first reaction is that the wind and fast drying time
would be the biggest culprit.  We have also done lime over earth plaster
with good results so I don't think tearing off the earth base coats is
necessary.

I would suggest taking off the lime coat in a small area and re-apply a
test patch of the same stuff under more desirable conditions to observe
if you can get better results.  Make sure to really wet the wall prior
to applying it.

Jeff Ruppert, P.E.
Principal
Odisea LLC <<a  target="_blank" href="http://www.odiseanet.com/";>http://www.odiseanet.com/</a>>

*/Front Range Office    /*        */West Slope Office/*
1460 Lee Hill Road, #7       337 Main Ave (physical)
Boulder, CO 80304              P.O. Box 1505 (mailing)
303.443.4335                        Paonia, CO 81428
303.443.4355 fax                  970.948.5744
                                                1.866.795.6699 fax
jeff@...
www.odiseanet.com



John Swearingen wrote:
> 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
>>
>>
>>
>>
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>> Version: 7.5.488 / Virus Database: 269.13.30/1030 - Release Date:
>> 2007/09/25
>> 08:02 AM
>>
>>
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>>
>
>
>
> --
> John Swearingen
> Skillful Means, Inc.
> Design and Construction
> www.skillful-means.com
>
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