[Strawbale] waterproofing the bathroom

André de Bouter m.ep at laposte...
Tue Jan 21 10:21:04 CET 2003

Re: [Strawbale] waterproofing the bathroom> The problem with gaps is that the mice like to live in them. 
The gap is also a higher risk for condensation, and (when we talk of greater surfaces) could act as a chimney if there were to be a fire behind that cladding etc.

I like Harald's suggestion to push tiles in the clay, but care needs to be taken on the joints as they will be the danger zone. 
The plaster behind the glued tiles needs to be absolutely dry and finished settling in order to prevent cracking. When Tom Rijven needs to garantee a no crack earth plaster he will wait for a year (the 4 seasons with their caracteristics)before he will do the last layer.

A bit further south than where you are, Marocco offers an other suggestion. Taddelact (or whatever is your favorite spelling)
A lime plaster that has been waterproofed by 'crushing it' with a stone during the curing and treated with what we call 'green' soap in Holland. (The grandmothers type). A very interesting technique that we want to try in our bathroom on our SB wall. Search for more info on the Internet, or take a workshop in Marocco with the experts. 
Little warning, it gives an absolutely beautiful finish, but may not be a simple owner builder technique. 

Martin Oehlmann suggested a natural paint from Holland that makes plaster waterproof. Seems the most simple to me, though (linseed) oil should also work. The problem is only, what if it doesn't work? 
How to detect any moisture problems in your sb wall before it is too late.
With a moisture meter, either bought at a farmers shop or hand made (see TLS no?)

  ----- Original Message ----- 
  From: Barbara Jones 
  To: strawbale at amper....muni.cz 
  Sent: Monday, January 20, 2003 4:26 PM
  Subject: Re: [Strawbale] waterproofing the bathroom

  Hi Rikki
  I agree with Herbert's thinking. You'd be best with some sort of rigid board that does not deform when wet to fix your tiles to such as heraklith, or there are some clay boards available commercially but not necessarily in your part of Spain. I'd try to only tile the bits that get direct splash from water and leave the rest breathable, and then there should be no need to leave an air gap. The problem with gaps is that the mice like to live in them. If the straw is loadbearing and therefore under compression, as long as you gave it a close haircut before plastering (to reduce bounce) I would think you could fix tiles directly onto the walls as you do for other wall systems. As far as I know, this hasn't been tried before, but let us know if you do it!
  Best wishes and good luck

  Amazon Nails: Strawbale building, training, consultancy, empowerment.
  Building With Straw Bales by Barbara Jones £9.50 post-free from Amazon Nails or from Green Books
      Warning! Strawbale building can seriously transform your life!   

    ----- Original Message ----- 
    From: Herbert Gruber 
    To: strawbale at amper....muni.cz 
    Sent: Monday, January 13, 2003 6:29 PM
    Subject: Re: [Strawbale] waterproofing the bathroom

    Dear Rikki
    Knauf is a gypsum-board, the problem is, that such boards (even the cement-boards) tend to make a bow, 
    when you fix the tiles on it or glue it to the wall (in combination with water).
    Better work with Heraklith-boards (3 - 5 cm, magnesium-glued) and fix the tiles with cement-based tile-glue (Fliesenkleber).
    You need no space between board and straw. You only need space when you have two materials - one cold (like stone) and the other warm (like strawbale) because of water-condensation or as a ventilation-space. In the last  case you had to make holes above ground and under the ceiling, so that the air could circulate. But in this case the damp would go in the bales. 
    So: Make no ventilation space.

    Best wishes


      I am thinking of putting panels of  pladur or knauf (a type of cement board) covered with tiles in the bathroom to protect the bales from the water of the shower (not yet installed), but i was wondering if I should put a layer of plaster under the board? Also, should I leave an air space between  the board and the bale wall, or should they touch? Does it matter?  

      any comments or alternative ideas are appreciated; I haven´t started the work there yet, so I  am open to other suggestions  . . .

      love , RIKKI 


      MSN 8 helps eliminate e-mail viruses.  Get 2 months FREE*. <http://g.msn.com/8HMUEN/2022>  

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://amper.ped.muni.cz/pipermail/strawbale/attachments/20030121/f7af1546/attachment-0001.html>

More information about the Strawbale mailing list