Tag Archives: cretestone

Leak if you dare, bathroom floor

DON’T ask me why I got so excited when I walked into the apartment on Thursday, 27 January 2011 and found two guys at work on waterproofing the bathroom floor. Perhaps because the drama of the big events — the knocking down and building of walls — had been over for a while, and nothing more dramatic than the chases for the electrical wiring and the first plumbing work had happened since work on the apartment started again on 10 January?

Phillip Davids and Justin Fisher, who work for Seamless Waterproofing and Coatings, applied a product called “derbigum” to the concrete floor of the new bathroom. Derbigum is what people in the building industry call a “polymer-modified bitumen waterproofing material”. It is black and feels like a rubbery gum, and was melted with a blowtorch before it was pressed down onto the concrete floor and around the two water outlets in the floor. I noticed that about 80mm or so of the walls at floor level also received a coat.

The derbigum-coated bathroom floor, before the bitumen-paint topcoat was applied. The inlets/outlets in the two walls are for the hand-wash basin (left) and the toilet (right)

Once the derbigum had dried, it was covered in a coat of bitumen paint, which made the floor surface look as if a thousand dusty shoes had stomped over it, and then the walls of the shower area were painted with a waterproofing membrane called Cemflex. The latter product was applied straight onto the cement walls, and gave the cement a kind of permanently wet look.

The walls surrounding the shower area before the Cemflex was applied
In this pic the Cemflex had been painted onto the walls behind Lunga Kwayini, the tiler. The bitumen paint had also been applied to the derbigum on the floor

I also noticed that the Cemflex was painted over the derbigum right around the bathroom where the walls meet the floor, creating a kind of a Cemflex skirting board.

When all these waterproofing products had dried thoroughly, the bottom of the one bathroom wall that will remain untiled was finished off by continuing the CreteStone plaster over the derbigum-Cemflex “skirting board”, right down to floor level.

One can clearly see the band of CreteStone at the bottom of the right-hand wall in this pic. The Metro tiles had already been laid, and the untiled wall had received a coat of primer paint

After all this waterproofing, the bathroom was ready to be tiled and the slatted-wood floor could be installed. Onwards!

Sunday, 20 February 2011

Update: The stipple solution

LATE in December, I had an inquiry about the two tests our builder did to determine the most effective way to get rid of the stippled plaster that was used by the original builders of our apartment (see post, “Day 7: The rubble has left the building“). The person, who stumbled across my blog on Google, faced the same dilemma when his/her renovations started on January 3.

Our builder tested two skimming techniques: in the first, an area was chipped with a small chisel before applying “permabond” and then a 3mm layer of CreteStone; in the second, the permabond was applied without chipping the wall first. Because almost all wall areas in the apartment had been stippled, we really hoped that it would not be necessary to chip the walls first.

The two test patches can be seen in the background: the one on the left was chipped, the right-hand one not. When this photograph was taken, the permabond had been applied, but not the CreteStone

When I received the inquiry, I bothered Karin on her holiday to make sure I got the facts right before I replied to the question, and here is her advice:

“In the end, we skimmed the walls without chipping them first. However, you should do a test on your own walls as well, because walls may differ, and the technique that worked for us may not necessarily work for you. Do a test on two 1m x 1m areas, and let the CreteStone dry for at least a week before inspecting them and taking a decision. When the two test areas are thoroughly dry, inspect them carefully for hairline cracks before deciding which technique you want to follow.”

I hope this advice helps you to slay your own stipple!

6 January 2011

Day 7: The rubble has left the building

OUR building contractor is most certainly very hands-on. By three o’ clock this afternoon the pile of bags filled with rubble — which has rather started resembling the Tower of Babel — was gone. The excellent idea Karin Cronjé, the project manager, had to construct a wooden chute down which the bags would slide onto the back of a truck became unnecessary when the building’s caretaker allowed us simply to toss the bags over the balcony onto the truck. This was always the easiest solution, but we did not contemplate it because the body corporate has strict rules for removing building rubble and where vehicles are allowed to park.

With only 11 days left before the start of the annual builders’ holiday, Karin is pushing to have all the “wet” work completed so that everything can dry out properly before work starts again in January. The builders have almost completed all the new walls, and have already started plastering some of them.

Another job which Karin aims to complete before 17 December is the skimming of all the existing walls in the apartment. At the moment all the walls have a stipple effect, which seems to offend everyone from Karin to the building’s managing agent. I found Patrick Toontjies testing two skimming techniques in the future guest bedroom to figure out which one works best: in the first test he chipped an area before applying “permabond” and then a 3mm layer of CreteStone, and in the second he applied the permabond without chipping the wall first. I suppose we hope for the second technique to work.

I learned two new words today: a “float” is the thing with which Patrick applies the CreteStone to the wall, and a “hawk” (a square board with a handle underneath) is the thing from which he scoops the Cretestone. Hell, there’s an entire new language out there to wrap my head around. Now I only have to figure out whether “permabond” and “CreteStone” are proprietary names or not.

Karin and I are meeting at the apartment tomorrow morning to discuss details like where we should position the shaving mirror in the shower, and whether it is really necessary to have a second side wall in the kitchen — all things that make me dream of moving in within the next two weeks. Fat chance of that, though.

Patrick Toontjies testing techniques for skimming the existing walls to get rid of the much-derided stipple
Against the new wall in this photograph we will have a dishwasher, sink and fridge, with cupboards above
Jeffrey February, Patrick Toontjies and Conrad Swarts level fresh plaster against a new wall in the future sitting room. This wall will be covered in bookshelves one day

Thursday, 2 December 2010