Sunday, September 21, 2014

Catalan vaulted roof/ceiling

This was a project done last year and  I thought I had made a post about it, but looks like I did not.

After several small span  Catalan  roofs  we decided to roof this room using our new skills.  This method is referred to by many names:  Catalan, timbrel, cohesive tile.  I will use Catalan.

(Note the modern scaffolding!)

First we built end walls to draw the catenary shape  templates, run strings to control the shape, and "glue" the tiles.
  I bought handmade  floor tiles for the first course for aesthetic reasons.

 Butter two sides of a tile with gypsum plaster.
Tap into place and hold 1-10 seconds.

And then move on to the next one.  It is a bit tricky as the first one has to be "set" so better to build in two places or use gypsum that is almost set.
  A video is found here

Building on each side .

Conduit pipe for ceiling light.

From above 3/4 done with first course of tiles.  Sometimes extra gypsum plaster applied to help hold until an arch is completed.  gypsum gives no strength to the vault, it is just to hold until an arch is finished.

About to close the first layer.  We were excited about how good it looks.

 After finishing the first course.   We had disagreement on whether to do the other 2 laminate layers as we went along or finish one course at a time. 

It did bring and issue .

Before I talk about the hole.  This shows the 2nd and third courses with different bonds, first at 45* then at right angle to original bond.  After 24 hours you can stand on the 3 layers.  Mortar is cement - lime - sand  1-1-6.

Mason Dickson preferred to finish first course then sit on the end wall and lay 50cm of other courses, next day sit on the first 50 cm and lay another 50cm.  Worked okay until someone put something heavy on current days work and it collapsed!

As it dried out efflorescence occurred on the beautiful tiles but i figured it would dry and fall off like our bricks.  It is a year and still ugly like this.  I just tried washing it off and that looks like it will work.
we filled in level and then put heavy plastic and then 5cm concrete sloped into a drain pipe.

On a small Catalan vault we roofed with tiles to see how well that would waterproof the roof.


  1. This is awesome Erik. Haven't checked out you blog in a while but I'm really glad you're experimenting with all these arches. I just wish that N America had more opportunity for these "aternative" (they've only been used successfully for centuries) styles of building

    1. Thanks for commenting Sean. So you cant becuase of code or permits?

  2. Erik, is there an advantage to finishing the first layer before you start the second? Because I think I would run the first layer to arms reach, then start the second so I could work both layers off the same scaffold set up.

    1. I think you should do all three layers and then move the scaffolding. then second day you have no problem putting tools and mortar on the previous days work. I let mason dickson do it his way but think it was wrong. Unless you are going to run plastic over the whole thing and then do thre layers .

    2. thanks for bringing it up.

  3. Erik, primary code issues here have to do with energy code. We're required to provide an R30 roof assembly, unless we can demonstrate whole building energy performance to offset that. We specified catalan vaults for a recent project but had to cancel due to lack of local labor and ability to get an accurate bid. I've since solved those issues and plan for a future effort! Thanks for sharing. David

    1. where you located? what kind of project.

  4. Erik, I've got our 12x 17' shed far along, foundation poured, walls built to 8'. Just designing out the catalan roof. Wanted to know if you had any feedback a year later on this structure & roof.

  5. start on something smaller. are you going to do thin tiles? how much rise? is there a tie in the middle? 17' it will have great outward force in the middle of the wall.
    carefull on the second course that the gypsum on first course does not get excessively wet. dont water proof until the ceiling is dry, as then it will take forever to dry. i used clay-sand-lime 2" and then limewash to make it water resistant on buildings after this one.
    send pics erikrowberg at gmail

  6. Bonjour, je suis de Madagascar et je construis des voûtes aussi et je voudrais savoir comment vous avez solutionné l’étanchéité du toit, avec quel mortier, pour ma part j'ai opté pour le toit végétal avec du plastique classique mais il faut surveiller régulièrement et ne pas marcher dessus. sympa ce que vous faites

    Hello, I am from Madagascar and I build vaults too and I would like to know how you have solved the waterproofing of the roof, with what mortar, for my part I opted for the green roof with conventional plastic but it is necessary to monitor regularly and do not step on it. nice what you do

  7. Andre. Thanks for posting and sharing your link. you do interesting stuff. I will comment more on your site.

    I have tried many ways to waterproof roofs, including green roof like you. But the clay-sand-lime-ash works the best but i lime paint every year and sometimes there is a repair. i will write a post about it

    I talk a bit about it here.

    1. The mixture i use is 3 clay, 5 sand, 1lime, 1/4 ash. you experiment with ratios.