Re: Damp issue & advice on products for decorative concrete
(1) The look you're trying to achieve seems to be a polished cement. We do have a decorative polished cement coating which we are planning to put online this month.
Otherwise, Arcacolours simply tints the concrete your would be laying. Other than the colour, it would not change the aspect and look of the concrete. However, you can obtain just about any nuance of colour you wish by dosing the Arcacolour added to your concrete powder (see product data sheet ). The powder dye is added to the dry content of your cement mix (see our application video for explanations of adding Arcacolours). The colour might fade in time when applied to an outside surface subject to a lot of sun.
(2) Arcadamp is micro-porous and will allow the substrate to breathe. Applied on the inside wall, it seems to be perfect for the problem you're describing. As far as the joist is concerned, there are many solutions but I would need a more detailed explanation in order to recommend the best solution. Do you have (or can you make) pictures of the area concerned? You can apply Arcawood which will protect the joist itself from water penetration, damp and damage . But I'm wondering if the you shouldn't also waterproof the surrounding (and problem) areas to attack and solve the problem at its source.
Don't hesitate to contact me if you have any further queries.