Appropriate cover for self-leveling compound

[ruadh]

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?

[woodPixel]

Just did a manky garage floor with this: https://www.bunnings.com.au/lanko-5k...eller_p0760338

It was gravel, terrible concrete and clay underneath. A right mess. The crap was removed and set with cement, then this poured over the top for a fine finish.

On top is battens and yellow tongue.

But if it's just for storage and understair, why bother with a super dooper finish? Bog it up!

[ruadh]

But if it's just for storage and understair, why bother with a super dooper finish? Bog it up!

Lanko is the sort of thing, but I was looking at Ardit or Sikafloor. The epoxy finish was because I wanted a consistent look across the whole workshop. However, if foot traffic damage is the weakness with these self-levelling compounds then I was concerned that epoxy would be too light a protection. Certainly it’s a long way from yellow tongue in that regard. However if the issue is light exposure then epoxy might be perfect cover. Anybody know why self-leveling compound must be covered, and what constitutes acceptable cover?

[Beardy]

Lanko is the sort of thing, but I was looking at Ardit or Sikafloor. The epoxy finish was because I wanted a consistent look across the whole workshop. However, if foot traffic damage is the weakness with these self-levelling compounds then I was concerned that epoxy would be too light a protection. Certainly it’s a long way from yellow tongue in that regard. However if the issue is light exposure then epoxy might be perfect cover. Anybody know why self-leveling compound must be covered, and what constitutes acceptable cover?

Where are you getting the self leveling coating must be covered? Traditionally it is used as a prep coat for floor coverings but I wasn’t aware it must be covered, have seen it and used it to repair factory floors over the years without an issue.
Just a side point, the existing slab may not have a membrane under it so be mindful of any finish coatings / coverings you use that may be effected by rising moisture

[ruadh]

Where are you getting the self leveling coating must be covered? ...
Just a side point, the existing slab may not have a membrane under it so be mindful of any finish coatings / coverings you use that may be effected by rising moisture

• Can only be used on concrete floors. Not suitable for driveways or areas subject to vehicular traffic. Must be covered by tiles, carpet or vinyl.

• [my emphasis]Dunlop DIY - Dunlop Ardit Floor Leveller

That’s from Dunlop’s Ardit instructions.

On the side point, I’ll certainly test for moisture emissions before I commit to installing epoxy.

[ruadh]

Where are you getting the self leveling coating must be covered? ...
Just a side point, the existing slab may not have a membrane under it so be mindful of any finish coatings / coverings you use that may be effected by rising moisture

From Dunlop’s Ardit instructions:

So, I looked up the equivalent instructions for your suggestion of Lanko and I think I found
my answer.

Lanko 173 Floor Leveller is not a wearing surface and must be protected with a compatible topping, floor covering

or coating.

Davco Floor level Lanko 173 .

That is, it is the ability to stand foot traffic or other wear that is the deficiency with self-leveling compounds. In which case epoxy might be okay, particularly since the Larko instructions allow coatings which the Ardit instructions do not.

[woodPixel]

That floor is dry as a bone. Dig it out a bit and just fill it with concrete mix. Level it with the floor and paint it.

Easy peasy.

[ruadh]

Dig it out a bit and just fill it with concrete mix. Level it with the floor ...

Yes, but this sounds like more work than just sealing and self-leveling.

[ruadh]

That floor is dry as a bone. Dig it out a bit and just fill it with concrete mix. Level it with the floor and paint it.

Easy peasy.

So, I went ahead finally, laying out 19mm width wood formwork, scribed and cut to a level with the highpoint across the the uneven floor cross section. The formwork was set for the north and on each line edged at the perimeter drain on three sides and on a diagonal. (c. 0mm to 30mm high). On the south end, there the existing uneven surface went right to the besser brick walls, so I just taped along the level and poured to it. At the exit (where two parts of East side formwork and the diagonal converge at the high point) there was a small gap with a drop (0mm to 4mm to 0mm) across maybe 15mm and I just made a rough form with wood scraps to bridge the gap. This edge, despite it's minimal dimensions, failed during the pour. I had to top this up as the mix escaped and so you can see a tiny circle of uneven concrete (100cm diameter) which I'll fix manually.
IMG_5729.jpg
IMG_5731.jpg

And then poured and set:
IMG_5894.jpgIMG_5900.jpg

The result is fully level though the formwork is a bit high in places by a mm or two (poor carpentry) and I'll cut it down. I'm putting in ss grates 25mm X 100mm above the perimeter drain, with a 16 gauge ss angle (25mm by 25mm). The angle will seal the edge of the vinyl floor that I'm laying.

[ruadh]

That concrete leak in the pour was 100mm in diameter, not 100cm!

[ruadh]

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. Angle grinder removed concrete bulge just above floor level.jpgConcrete grinding in context above installed vinyl floor.jpg

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.

Formwork added to guide grinder.jpgFormwork guides on other side.jpg

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).

Completed ground ledges.jpg

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.

[ruadh]

That floor is dry as a bone.

woodPixel July 2018

Sorry, in thread quoting just gives a bouncing blue ball.

So, the basement garage has been dry throughout, and still is. But if you look carefully at my most recent photo, you'll see that there is water in the perimeter drain (it cannot be seen normally because of the drain gravel). That it's wet is not surprising after the equivalent of 7" of rain here in the previous two days (since 9am we've had another 3", and will surely have a full foot of rain before the day is out). However, the drain appears to be doing its work and the slab remains dry.

[ruadh]

Stainless steel drains now installed and level (a little fine tuning still required to get them all at the same level but only a mm or two in it. )

Note that, four days after the drains below were running following torrential rain (317mm for the week, or in Imperial terms, over a foot of rain), that water has wicked up the walls at the corner, top left. The drains below are now empty, but remains to be seen if this moisture has any effect on the levelised concrete. In the 18 months that I've been doing this project, the perimeter drains have been empty.
Floor leveled, covered with vinyl, and ss drains added.jpg

[ruadh]

Next steps. I now completed some long term maintenance that had been overlooked. The spandrel ceiling had some honeycomb concrete, with some exposed rebar and wire. This has been fixed in recent years throughout the common areas of the building, but not in the the private basement/garages. I should get the strata to do this, but it was easier to do it myself, rather than slow my project waiting for this to be done.

Exposed rebar.jpgEpoxy cover of rebar.jpgMortar cover of rebar.jpg

There were about five or six holes needing filling. These photos are just an example of one. The first photo shows the honeycomb concrete and a hole with exposed rebar and wire. The holes were opened up with a cold chisel and hammer, and then the wire was cut back with bolt cutters as much as possible, then the remaining exposed metal was polished with a wire brush. I was surprised how little rust there was in what is quite a humid environment. The second photo shows a two part epoxy covering applied to block air access to the metal. The third shows a mortar final cover applied. In the second photo, I noticed a dark spot to the left of the main hole and then realised I was missing some exposed rebar, which I treated, so that the mortar cover is larger in the final photo.

I didn't mention earlier, that when I started this job I washed the walls with dilute Hydrochloric Acid to clean the mortar stains left over from the original build, that had never been removed (see first photos above).

[ruadh]

Having got the floor levelled, drained, and covered, and the ceiling patched for honeycomb concrete problems, I then was ready to install my storage facilities.

This comprised:

• three bookshelves on the left hand side and two metal louvre panels on the back wall for pick buckets. Shelves and louvre installation .jpg
• single track and twin track shelving above the book shelvesSingle track and twin track shelving installed above shelves.jpg

I bolted the shelves to the walls with star plugs with 10g metal screws (8g countersunk wood screws to wood) across a zinc coated steel plate for weight (less load on the ss grates) and safety (tipping hazard) reasons: Bolting shelves to wall for support.jpg