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.  

 

[Dave-1]

Good Afternoon @SamMac 

I was trying to remember the name of the product I used at my place for sealing the edge of a patio and the brick wall from stormwater. Then you said Sikaflex and the lightbulb went off!

I used black sikaflex to seal my patio and brick wall. There was about a 1cm to 1.5cm gap and I just filled the hole with it. No more issues

sika 310ml grey concrete sikaflex pro polyurethane sealant This one is grey and may match your edge nicer.

Id also like to say howdy and welcome to the Bunnings community page Lots of similar questions to yours in here and def worth a wander.

Dave

[SamMac]

Thanks @Dave-1 . Have had a look at other posts so got an idea of what kind of info and photos to put in the question and some very similar questions on here, but none I've seen have mentioned backfilling as of yet, might be something I've missed. 

[Dave-1]

@SamMac 

The backfilling is just the way I went, I did think of a tar like substance but that might look pretty messy. Something flexible taht will move when the building moves with the weather. I was presuming thats how your gap shows up.

Water issues are a pain but at the same time its nice to solve them.

Dave

[SamMac]

Yes I think it's just moved apart with age and time, built in 1960's. I figure sand and backing rod is fairly flexible to fill with and proivde a base for the layer on top.  How thick a layer of silka though 5mm or just the surface?  

[Dave-1]

@SamMac 

I hesitate on the idea of using a backing rodd or filler. To me an easy fix in this case may be better (less materials to go wrong). I just had a look at sikaflex website itself and the spec sheet and it really looks like you could use it for the whole seperation area.

sikaflex pro plus Down the bottom of the page is the data sheet for the product.

Dave

[EricL]

Hello @SamMac 

Welcome to the Bunnings Workshop community. It's marvellous to have you join us and thanks for sharing your question about filling the gap along your wall.

It's great that you've received excellent advice from @Dave-1. 

The purpose of the gap filler rod is to prevent the Sikaflex from flowing down the gap. It's just a temporary holder and once the Sikaflex cures on top of it, it will no longer have to rely on the gap filler rod. I believe a 5mm space should be enough to provide a sufficient seal.

Please make sure not to push the gap filler rod too deep into the crack and remember to leave space for the Sikaflex to settle on.  

Please remember to wear personal protection such as gloves, goggles and a face mask when working on your project. 

If you have any other questions we can help with, please let us know.

Eric

[SamMac]

Thanks @EricL and @Dave-1 I misinterpreted the purpose of the filler rod to 'fill' completely rather than provide a 'base' for the filler itself. Will give it a go with depth to width ratio as per Sikaflex guidelines.

[MitchellMc]

Please keep us updated @SamMac and reach out if you need further assistance.

Mitchell

[Dave-1]

Morning @SamMac and @EricL 

Well I just learnt what a filler rod does First new thing for the day! Looks like I will be wandering down that aisle to have a squiz the next time I am in Bunnings!

Dave