Rendering - Technique & Colour

[Sancho]

I am in the process of building a brick dividing wall in an outside area. One side will be tiled (no doubt the subject of a later post) the other I'm planning to render and colour.

I am a complete novice with brick, cement and render. So far the wall is going okay but I need learn more about rendering before I start that part of the process. The best I can find in these otherwise excellent forums is from schwerdty:


Ok mate, this will make it all simple for you. Buy premixed render in a 20 or 25kg bag. A bag will do 3-4 square metres and cost 10 -16 dollars. Follow mix directions and make to consistency of toothpaste or slightly wetter. Do not add anything to it. Hot day, wet wall half hour before. Next trowel on mixture from top down using rectangular trowel. Make reasonably smooth and keep it thin on the wall. Don't worry about those raised ridges, they will disappear in second coat. Do whole wall working left to right or vice-versa. A couple of hours later you can use the edge of your trowel and scrape back the major ridges. Don't be too pedantic, just the bigger ones. Time to do second coat. Mix slightly wetter than first coat and apply in same manner but really apply as thin as possible. 1mm really. You need to purchase either a base render float (plastic with diamond markings on the under side or a poly styrene float.(I don't think bunnings sells the appliers. If you want cheap render and tools for the job go to insulcon in dandenong and pay cash.) Work with two people. One trowels very thin, the other (when it goes off - you remember - when the shine goes) presses and rubs in circular motion from top down, working the mix using gravity to leave any excess on the ground. This takes practise, so do it in the hidden area first. You will have to do an entire 'face' of wall in one go. Two weeks later you can apply top coat or just paint it with long nap roller. Post if you want top-coat info. (I render other people's property so I know what's going on.)


I didn't see anyone challenge him so I take it this is sound advice. Anything else I should know?

I also plan to have the wall coloured. I'm thinking about using a render colour - or would I be better off painting the finished wall?

Regarding the colour addition - I take it you only apply that in the 2nd coat? And is there a colour chart to give you a rough idea of what it looks like? Bunnings just sold small tubs with a name - "Sand" - "Sienna" etc but no display of what the finished product looks like.

The finished texture isn't too important tho I'd prefer a slightly rough finish - how would I best achieve that?

[Dirty Doogie]

Hi Sancho and welcome to the forum. The technique described above is pretty spot on and there is nothing I could add to it - except that for a final finish you can just use a flat piece of polystyrene foam - such as you would find in packing material. You dont actualy need a foam trowel.

The trick to getting an even color in your finish coat is to mix the oxides in the total batch of render mix while the powders are dry. A cement mixer is necessary - mixing in barrow just doesnt cut it.

I dont know of any color guides for render mixing. It is a matter of experience with using render mixes and even then some experimenting is necessary. Generally colored render dries about 2 shades lighter than how it appears wet.

I would suggest that you use the basecoat render mixes to experiment with colors - it is a lot of fun - and you might feel confident to try for your desired top coat color. Be aware though that some colors bleed - especially Oxide reds and browns.

If the colors go all wrong you can always over paint with a flat acrylic - which is how a lot of renders prefer to work anyway.

[bugsy]

i would paint it brown and gold