# Another vault.



## Fundi (Jan 5, 2009)

We had been talking to an architectural firm in Dar es Salaam for awhile. This year they got a job for primary school and designed with vaults and arches (thinking of us). They can't get clay bricks in Dar and build permits needed so they went with cement paving stones and building the arches on formwork. Much more engineering and design and stamps than we have done. arches are two in middle of room of 6 meters and then 3 vaults on them and the walls.


Not what we like to see but it is a job. We havent had a vault job since early in the year Now they want to do one classroom with clay bricks vault. So Dickson has gone 200 km away looking for bricks. 

Dar is 700km away and just sent Dickson and a helper. So i rely upon phone and pictures.

We only do the vaults and arches the foundation and walls are someone else.


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## Fundi (Jan 5, 2009)




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## Fundi (Jan 5, 2009)

oops meant this for the picture section.


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## JBM (Mar 31, 2011)

Always impressed with your anti gravity masonry skills!


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## artisanstone (Nov 27, 2007)

Fundi, can I come work for you? How's the pay?


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## Fundi (Jan 5, 2009)

artisanstone said:


> Fundi, can I come work for you? How's the pay?


I wish you would / could.


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## heavyc (Jul 2, 2013)

How long does something like this take? Looks kinda warm there. What is the mortar type used?
Great work.


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## 91782 (Sep 6, 2012)

Fundi said:


> oops meant this for the picture section.


No, no, this is way cool being here!(Serendipity)

I was just thinking about you today. I've been researching clay and brick dwellings, and stumbled on this guy at a TED talk: Diébédo Francis Kéré

https://www.google.com/search?q=Dié...gpuVdazN8jRoAS_7YDwCA&ved=0CAYQ_AUoAQ#imgrc=_

Every time I look at one of your posts here, it gets me motivated.

Thank you!


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## dom-mas (Nov 26, 2011)

So glad you're posting again. I liked the exterior architecture at my highschool, the interior was blah...that school on the other hand is just inspiring...as it should be


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## Fundi (Jan 5, 2009)

SmallTownGuy said:


> I've been researching clay and brick dwellings, and stumbled on this guy at a TED talk: Diébédo Francis Kéré
> 
> https://www.google.com/search?q=Dié...gpuVdazN8jRoAS_7YDwCA&ved=0CAYQ_AUoAQ#imgrc=_


Wow! Thanks for that. I can't believe I have never come accross Diébédo before. I have to check him out more.


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## Fundi (Jan 5, 2009)

heavyc said:


> How long does something like this take? Looks kinda warm there. What is the mortar type used?
> Great work.


time: varies but about 3m(2) per day. Dar is hot. mortar in this case is homemade but type S.

Mortar in next pictures is clay sand.


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## Fundi (Jan 5, 2009)

Architect wanted to try some vaults in clay bricks. So now formwork is only used to mark the shape on end walls. 

Mortar is clay sand. 

























Bricks dont look as good as mine but better than the first one in last picture.


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## dom-mas (Nov 26, 2011)

Never having worked with a clay/sand mortar I'm guessing it only works with a clay product? Is that becaase of the absorptive properties of the clay unit or something else?


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## Tscarborough (Feb 25, 2006)

I think it only works because the structure is in compression, the mortar is holding the brick apart, not together. There may be a very slight hydraulic set, but not much.


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## dom-mas (Nov 26, 2011)

In most modern masonry i would say the same, that the mortar is holding the units apart...it;s acting a sa gasket between the units, but here he doesn't use a centre for the vault when he's using clay mortar so the mortar has to be holding the units together, same as fireclay and firebrick


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## JBM (Mar 31, 2011)

How many 2x4 legs would be have trying that!


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## Fundi (Jan 5, 2009)

dom-mas said:


> Never having worked with a clay/sand mortar I'm guessing it only works with a clay product? Is that becaase of the absorptive properties of the clay unit or something else?


Exactly dom, it is the absorptive properties that allow capilliary action on the bricks to keep a brick in place while building one arch in the vault , until the adhesive properties of clay take over. so it doesnt work with a clinker brick. After the arch is finished the dynamics change. 

After the arch is finished it is keeping the courses apart like Tsar mentioned and dealing with irregularities of the bricks. Compression comes in AFTER the one course is finished. 

I could work on a cement product that is somewhat porous and thinner. Just as if the clay brick were thicker compared to length it would be harder. So you need a good sized face and not too thick.

Did i ever post pics the the timbrel / catalan vault ceilings? I cant find on CT. There the first layer of clay tiles are put up with gypsum as the adhesive. 

It is also interesting that we put nothing on the ends of the brick while building an arch. After the arch is done the extrados are "open" and where the radius is sharp it could be even 2cm (3/4"). there is a possibility with loading on one side it could move so we lightly tap stone chippings into the extrados. Mortar could work but only after it is dry.


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## fjn (Aug 17, 2011)

Thank you for sharing,besides the beautiful projects,you take some great photos !


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## blacktop (Oct 28, 2012)

Very Impressive Work !


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## patrick grey (Jun 13, 2013)

Excellent work .the Spanish and the Mexican,s have some really good videos on YouTube doing the boveda Catalan (Catalan vaults)and the escalera catalan.they use a soupy kind of mix with lime in it ,very tacky stuff .the mix they use is posted in the comments section on one of the videos.


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