Balcony renovation - construction of slope

[chillichi]

The balcony of our house, which was built in the late '40s, is in need of renovation. In the existing construction, the balcony slab was sealed with a thick layer of asphalt, on top of which some kind of leveling compound was cast for slope, and on top of that were tiles in mortar:


I think the slab looks OK, there are no cracks, although there are some damages along the edges and weathering on the top edges under the drip edge (probably due to the worn-out waterproof layer). The edges have been patched/repaired previously, but not by me.





The balcony slab is completely level and thus lacks slope. My idea is to build up a slope first and then apply a new waterproof layer on top, and decking on top of the waterproofing.


Does this sound like a good way forward?

To build the slope, I had planned either some repair concrete that can be cast in thin layers, such as Weber REP 920, or some leveling compound for outdoor use like Finja 260. For the casting, I thought of building a simple mold from masonite held in place by the balcony railing's fixtures.

As a new waterproof layer, I was thinking of using Mapei Mapelastic, which according to the data sheet can handle decking placed directly on the waterproofing. Decking on the slab and tiles in the upturn against the facade.

A couple of considerations I have are:
- Movement joint between the built-up slope and the facade, is it needed and what would be suitable, perhaps a few layers of construction plastic or thin cell foam (10mm)?

- The embedded threaded rods for the balcony railing are rust affected, and some frost damage has occurred around them. Is it advisable to paint them with some anti-rust paint before I patch/repair the edge?

- Before the new waterproofing can be applied, the brick needs to be plastered or patched to make it even so the waterproofing can be applied, what would be a suitable material for this?

 

[Andreas Lundgren]

Are the rebar rods still okay then maybe start by cleaning them and then play with zinc spray for cold galvanization perhaps? Although I'm not sure if it can have any negative impact since half of the steel is embedded...