Waterproof cement - looking for the right product(s)

[dalston]

If you look at the picture below you'll see that I had to take out a wooden window sill next to my shower as moisture/damp had started seeping into the plaster.

I intend to simply recast a new sill out of concrete by fixing plywood sheet to the wall and fill the empty space. I have been advised to use waterproof concrete and need some recommendations.

Homebase is right next to my workplace so I am keen to pick up their Cementone rapid set kit. But if I do, I will need to add a separate waterproofing agent.
Can you guys please tell me what I need to look for? (Don't trust the staff in Homebase…)

Or if I have to I will have to travel a bit further to Screwfix and pick up a Cementone Rapid setting Waterproof Cement. Sounds OK?

All advice appreciated.


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[dmplastering]

As far as im aware, homebase dont stock waterproofer. And even if they did i would assume that it is hugely overpriced along with 99% of their stock.

I would go with the screwfix option

 

[handyman77]

http://gbr.sika.com/en/solutions_products/Construction/02a024/02a024sa04.html

Check out the Sika proof. I think some b&q are now stocking this.
If not any decent builders merchant.