How to fill gap between wall and concrete pation and crack along bay window?

[SamMac]

Hi Bunnings Team, a question on this crack. 

I have a crack between the brick wall and a concrete patio area that then bends round beneath a bay window. As seen in the pictures the gap is about 1cm wide, and the depth varies from between 10.5 cm against the brick to 3-4 beneath the window. Wondering what the best way t0 fill this would be.  My initial thought was back fill the crack with paving sand then put a backing rod e.g. Moroday 10 mm on top, then Silkaflex Pro+ on top of that ( not sure what depth to do the silka to ie between top of rod and the 'ground' level). But also thinking a sturdier option might be to fill with Dunlop Ardit (which I have on hand from patching other concrete areas) particularly for the section between the patio and under the white painted timber of the window as on the other side it all sits flush together. My main concern is water getting in the gaps etc. 

Any advise on what I'm looking at and how to go about it appreciated.  

 

[SamMac]

Thanks @MitchellMc , and @EricL and @Dave-1 , here is how I went about it this morning.

First I brushed the area clean and got out any debris from the cracks near the surface with a wire.

Then I applied the masking tape.

I then put in a 10mm Moroday backing rod to a depth of around 10mm – the backing rod naturally settled between the patio and the mortar of the brick at around this depth, in other areas I pushed it in with a caulking tool (the curved smoother end) to around the same depth though it was uneven under the window bit. The sika flex product guide indicates a joint depth of 10mm and width of 10mm is ok, so went with that,  in the uneven sections there were some slightly deeper and shallower areas but didn't get to fussy on them so long as there was at least a depth of 5-6mm..

I then applied the Sika flex, along the length then using the caulking tool pressed it gently down a bit onto the backing rod, the applies another layer and smoothed out. Then removed the masking tape and smoothed a little more where the edge to the masking tape lifted a bit, then tidied with a kitchen handy wipe. Not perfect finish but should be OK.

There are a few more sections to do along the place but will see how this cures over a week or so first.

[MitchellMc]

Great work @SamMac! 

Many thanks for sharing your results and how you went about achieving them. I'm sure they will be very helpful for any members referencing your discussion with a similar issue.

Mitchell

[Dave-1]

@SamMac 

Now id be happy with that! It As they say "looks like a bought one" It looks good. 

Thanks for showing us how you went about it, makes it easy for another person with the same issues

Dave

[SamMac]

Exactly, figure someone else will have a similar issue so start to finish pics would help. Will update if there are any issues as it cures etc. Now to the next job!  

[SamMac]

As a further follow up a few months later everything is still in place, but a mistake I made is that I put in the filler too 'concave' - dipping inward, rather than pushing outward so it collects dirt a lot, a flatter or convex application would have been better, so I may need to pull out and change at some point. But that is my error, the combination of the backing rod (moroday 10mm white) and Sika Grey, links below worked well overall and is still firmly in place.

https://www.bunnings.com.au/moroday-10mm-x-5m-white-gap-filler-rod_p4061881

 https://www.bunnings.com.au/sika-310ml-grey-concrete-sikaflex-pro-polyurethane-sealant_p0083588

[Dave-1]

Afternoon @SamMac 

Wooohooo Thank you for the update! And love your suggestion about concave/face outwards. There have been a few people with similar issues and I will try and remember your job to show them. 

Dave

[SamMac]

Happy to help, I guess I wasn't sure how much caulk to use and obviously a concave finish will require more hence another tube perhaps, but long term of course better to get it right the first time, I did better on other sections but yeah hopefully someone learns from the mistake.

[Dave-1]

Afternoon @SamMac 

You just nailed why I enjoy admitting to my mistakes, If it helps someone else then its a win

Dave