[Cob] Attaching concrete roofing tiles to cob walls

[Dean Sherwin]

Saw the query, found an example among my pics of an old cob wall in 
Devon with clay tiles on top.  The top row is a curved ridge tile, 
that sits along a wider band of interlocking tiles below which are 
set sloping down from the wall on each side.  The top tiles are 
cemented or grouted to the ones below and that all stays firm even 
tho the lower level which looks to be set in cob may crack and 
move.  suspect the weight mainly (and the fact that the whole thing 
forms an inverted 'v' over the wall) ultimately keeps it in 
place.  Its obviously been there for many years, who knows how long, 
80 - 90 would be my guess.  I'll send you the pic, since I do not 
have a direct link to put here.


At 03:00 PM 5/10/2011, you wrote:

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>Today's Topics:
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>    1. Attaching concrete roofing tiles to cob walls (Hugh Withycombe)
>    2. Re: Attaching concrete roofing tiles to cob walls
>       (Scott Alexander)
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>----------------------------------------------------------------------
>
>Message: 1
>Date: Tue, 10 May 2011 23:38:01 +1000
>From: Hugh Withycombe <hughali at webone.com.au>
>Subject: [Cob] Attaching concrete roofing tiles to cob walls
>To: coblist at deatech.com
>Message-ID: <D2E7FA04-D1BE-499A-8775-A79B14708961 at webone.com.au>
>Content-Type: text/plain; charset=us-ascii
>
>Hey there to cob world
>I have a question about getting concrete roofing tiles to stay 
>attached to the top of cob walls.  My family and I have built a 
>garden wall, with bench seat, windows and arched gate as an 
>introduction to more complex cob projects.  Now that we are starting 
>to get regular morning frosts (Canberra, Australia) the curved 
>concrete roofing tiles with which I have capped off the walls have 
>detached.  I bedded them on with a slightly clay rich, straw poor 
>mortar mix which adhered well during the warmer months but 
>differential thermal expansion seems to have broken them free.  They 
>were stuck with about a 20 degree pitch and even loose the weight 
>still seems to hold them in place.
>So, should I worry at all or can someone suggest a better fixture?
>Hugh Withycombe
>
>
>------Dean Sherwin CPE
Certified Professional Estimator
LEED Accredited Professional
CONSTRUCTION COST MANAGEMENT
3, Cherry Street
PO Box 11
Media, PA 19063-0011
(610)892 8860
fax (610) 892 7862
costman at verizon.net