Tiling on Hemp Walls

The second bathroom was the last room to be finished, it could not be rendered because thee tiling had to go in first and I had not finished the mosaic tiling behind the toilet and sink. With the shower tiled in a mosaic pattern I wanted to follow this scheme through the rest of the bathroom. So as soon as I finished my TAFE Diploma in Building Design in November several evenings were dedicated to mosaic making.

Mosaic laid out upside down ready to go on wall

As with the earlier mosaic I chose and put together, and cut a little if they did not fit, the pieces of broken tile. I laid them out on a paper patters then as I completed each section I stuck clear contact to the front. I then cut the now stuck together mosaic into pieces about 300 - 350 mm square. These sheets of mosaic were then adhered to the hemp wall with tile adhesive. I pressed them against the wall with my rendering hawk so that the whole section would be flat, rather than having uneven areas where pieces of the mosaic were pressed down more than others.

Mosaic adhered directly to hemp wall

 The bathroom had been waterproofed and the waterproofing came up the walls just over 50mm. The waterproofing had no problems adhering directly to the hemp wall, care just had to be taken that no stray pieces of hemp got stuck in the waterproofing as this would have left an uneven surface for the tiles to be adhered to. Except ensuring that there was no loose hemp no special technique was used to adhere the tiles to the hemp wall.

White Adhesive

Grey Adhesive

I used a white flexible tile adhesive called "Gripflex" This worked well on both the hemp wall and the Magnesium Oxide Board. Unfortunately I ran out of this product, which had been recommended to me by the professional tilers who had done the floor tiling and wall tiling in the front bathroom. The same product was not available at the chain hardware store and so I tried to match up the properties of the product, but in doing so did not check the colour and ended up buying a 20kg bags of grey adhesive. I did not find out it was grey until I opened it at which time it was too late to take it back. Grey adhesive is not recommended for use with white tiles and white grout as any adhesive that oozes through to the top of the grout gaps has to be scraped back to prevent it showing along the edges of the grout.

Tiling with white grout

Tiling with grey grout not so good

Once the adhesive had set (and both the adhesives I used were quick setting meaning they could be grouted in 8 -12 hours after adhesion) I removed the contact on the front of the tiles and grouted them with a flexible white grout called "Kemgrout Flexible". By choosing both a flexible adhesive and grout I hope to avoid any cracking due to movement, although any cracking will be harder to see due to the mosaic pattern.

Flexible white grout

Along the top of the tiles where they abutted the hemp wall I ran a line of grout so that if the render did not match the width of the tiles exactly the bare top of the tiles would not be seen. However I had laid the tiles on the adhesive so that they would match the thickness of the render and for the tiles beside the window frame I ensured that they finished flush with the window reveal. The area between the window and the wall was tiled as we planned to install a mirror and shelf unit where the shelves were open to that wall and it would be easier to clean spills from tiles than a rendered wall.

Grouted mosaic

Finish along top adjoining hemp wall

With the tiling finished and the wall behind the toilet rendered we were able to get Len, our plumber, to come out in the week before Christmas and install the shower, toilet and basin. The only thing left was to render the last two bathroom walls.

Toilet and basin installed