3 Attachment(s)
Appropriate cover for self-leveling compound
I have a 6900mm X 6200mm double-garage basement workshop built in Besser blocks with a 3200mm high structural slab ceiling and concrete slab floor. Beyond that there’s a staircase at the back to our villa Unit home above, about 4500mm elevation from garage floor to top step.
In the garage proper I have a workbench, drill press, and lots of storage including 2400m X 2400m peg board, 5000mm X 2400mm X 570mm industrial shelving, lumber shelf of 5200 X 350mm, metal chemical cupboard, and 2 X storage cupboards. Outside of that I have a 4200mm X 1500mm X 1000mm loft added on the garage above the entrance. For that reason I’ve never used properly the potential storage under the stairs. I’ve just used it as dumping ground for garden materials etc.
Anyway, the day has come that I’ve used all that space as we’re painting and have a room’s worth of furniture extra to store temporarily. I cleared out under the stairs and immediately got the project bug. The space is L-shaped and roughly 2100mm X 2100 X 800mm wide.
Two thirds of the floor in this area (1.9m2 of 3.1m2) was left unfinished by the builder - it’s rough and slopes away to the back wall to a level about 10mm below the floor. This seems ideal to use self-leveling compound on. I can scribe the levels on board and thus cut level formwork. However self leveling compound needs to be under floor covering. Why is this? Is a flake epoxy finish as you would use in a garage adequate cover for self-leveling compound?
5 Attachment(s)
Project Progress report: concrete grinding of waste and drain footings
So, finally getting some momentum with this project. As stated above, the plan was to level an unfinished portion of the floor of my basement garage, under a stair, and turn it into extra storage. The concrete levelling is complete, but now I need to finish the surface, wall to wall.
An issue with using this spandrel for storage is wicking of moisture from the bluestone drainage gravel in the perimeter drain to any cupboards or shelves I might install. Also, it would be difficult finding a level for this furniture on uneven bluestone. (BTW Despite this being a long term project, I only discovered today that the technical name for the area under a stair is a spandrel.)
My solution, somewhat over the top, was to install ss drainage grates above the bluestone, thus creating an impervious barrier to wicking and getting a level floor, not just on the concrete, but wall to wall. I bought the cheap ones with plastic bases, rather than ss.
So, to install these I needed to:
- Empty the bluestone gravel from the perimeter drain (discovered that there's no ag drain installed - getting the whole perimeter drain inspected by a plumber to see if it needs upgrading)
- Installing ss angle fittings to the outside wall to hold the plastic drain base - these are removable if the perimeter drain needs to be accessed;
- The drainage grates are 100mm wide, and the perimeter drain about 80mm. I removed or trimmed my formwork to meet the 20mm difference. I found the walls and floor were not square in plan, so the floor had some add corner angles).
- Grinding the ledge thus created, around the new concrete floor, so that the top of the installed drains (c. 25mm) will match the levelised concrete (I could have set the concrete level higher instead, but this would have meant a step up from the garage proper, which I didn't want). In any case, the ledge created by the formwork, like the concrete proper, needed to be levelled too.
- I planned to use an angle grinder with a diamond cup grinding wheel and dust shroud connected to a shop vac.
- I tested this setup by finishing a section of the wall where a concrete leak from poor blockwork had filled the perimeter drain. I'd removed the concrete plug thus created by masonry hammer drilling and cold chisel work, but the resulting visible wall surface was uneven. The grinder worked well with little dust and I got the wall smooth to within about 20mm of the corner. Attachment 468435Attachment 468436
Note that I had already installed the vinyl covering required by the specs of the concrete leveliser. I was concerned that I would damage the concrete with the work I would be doing, so I followed the instructions to the letter and installed the vinyl early. In hindsight, this was probably a mistake, as it just exposed the vinyl to damage. However, I can always repair or replace the vinyl.
So, grinding testing went fine, but the job didn't. The space available to grind the concrete ledge was of course, the width of the ss drains, 100mm. So, no room for guard or dust shroud on the 100mm grinder. So, I sealed off the spandrel with builders film from floor to ceiling, taping down the edges to get a dust tight result on one side and above, but had to leave the floor and one side loose for access. Then I employed full dust mask, eye protection etc. I moved my shop vac intake to the out throw of the grinder, step by step, but probably didn't get that much of the dust.
In such conditions, it was impossible to see where my level was. I rigged up some jigs from yellow tongue and masonite scraps, attached to the ss angle supports, that meant I could feel (or smell, from wood burning) where the level for the ledges was as I ground. See photos of brown yellowtongue (to the right) and white masonite (above and to left) jigs.
Attachment 468437Attachment 468438
Anyway, after much dust, but safely, job done, a levelled base for the ss drains. The jigs worked only partially. I used them to find my initial level, but they got damaged by the disc and then I had to just work off my initial level as best I could. I reckon they were still crucial, as they allowed me to get 60% of job done. Yellowtongue was more durable, so if I was building jigs for this again, I'd use that throughout (but what I used was the scrap I had on hand).
Attachment 468439
There was a bit of fiddling to complete some concrete removal that the grinder didn't reach, at each end of the ledges and on the vertical part of the ledge (eg. bulges stopping the drain width fitting across the 100mm span between concrete floor and wall - the non-square walls meant that in some spots I needed not just to remove formwork, but to trim the levelised concrete as well).
Now to complete the floor with drain installation.
