Laying a concrete upstand on concrete base

[matsmith]

Hi

Our waterproofing bloke says we need to create a concrete upstand around an external bit of concrete floor (which has a basement underneath). We already built one out of engineering brick, and the upstand will take a wall, but we are removing this brick to do it in concrete.

I'm going to create the formwork with ply etc.

My question it this.

Can we simply clean off the concrete base with pressure washer and lay the upstand directly on? Will it bond? Or do I need to anchor it down with bolts? Or put some kind of bonding down?

Thanks

[Tony McC]

How big is the upstand?

[seanandruby]

Scabbled and dowels drilled in. H&S hire or similar.

[GB_Groundworks]

needs a full construction joint wants scabling then cleaning and id dowel it as well

https://www.youtube.com/watch?v=3a_tVlj8g4s

[matsmith]

Thanks for the comments

The upstanding needs to be the width of a double skin brick wall, and about 70mm high I think.

I have hired a scabbler but it has a rotating drum with little "bangles", rather than the type with multiple drill heads shown on that YouTube vid. It's REALLY slow to take any concrete off (especially in basement below, where I need to take 50mm off the concrete - yes you read that correctly)

Where can I hire a proper scabbler with the multiple drills instead of rotating drum? I called around loads of hire shops, none seem to have one... London anywhere

When you say "dowel it", what with? Can you get concrete dowels? Or should I use bolts? Or steel bars drilled into existing base?

[seanandruby]

Depending on how much you have to do you might be better cutting a rip and breaking with a breaker, 50 ml with a floor scabbler will take ages. There are specialist big scabblers that will do it in no time but cost the earth. Maybe some photo's will give us a better idea.

[rxbren]

Get an electric cut off saw with dust suppression cut several runs 10-20mm apart to depth needed. Break said cuts with a hammer and finish off with scrabbler to the desired finish