Pre dashing questions?

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I'm now getting near the stage of dashing over my existing house and my new build extension but have a few questions i'd like answered before im happy to start.

I've seen the finished colour/shade i like on other peoples houses but not sure how they've acheived them. The dash i'm wanting to use is called Sunflower which is a mixture of white and brown giving a gold effect.

Some houses ive seen dashed are lighter or darker than others. I don't want mine to be really light though. I know that there is white cement,normal cement,silver sand and normal sand but i'm not sure which combination to use.

The main concern is green mould that appears on some dash jobs i've seen. Some people using the same dash have moss/mould all over after 2-3 years where as others have none after 5 years on the same road. Is this down to the additives added when rendered or down to the sand and cement type? I've heard that silver sand is alot better at reducing moss?

Can anyone give any advice
 
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there are many colours of basecoat/background available to roughcast on which come in the form of polymers.
these bags come in powder form where you just add water,and are always guaranteed a uniform colour as opposed to guaging your own mixes with traditional methods.

the staining you see on the newly casted buildings may be rust running out of the chips, which some chips are prone to doing.
chips which are affected by this are highlighted in the specifications from the
suppliers www.rowebb.com/ - 3k
 
reading through the technical data sunflower chips are highlighted as susceptible to rust staining due to the high iron content in the aggregate. :cry:
 
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thanks for that info, where did you see that it has high iron content i had a look on that site but it just seemed to tell it it was made from flint shingle. I may have to find something that is similar but of a better stone.

this pic isn't sunflower but it does show where some of the discolouration is starting, normally seen under the slip cill but can be seen elsewhere as it ages. What colour of render dye is this around the reveals, alot of buff or a little brown? View media item 9416 [/img]
 
where did you see that it has high iron content
i have the technical spec tables in a book! all the dashing aggregates which are succeptible to staining are highlighted with a red border. this is always pointed out to potential customers and the choice is then up to them.

its difficult to tell from rhe pic but i cant see any staining!! if you are talking about the shading below the cill that looks like a tidemark from water.......cleaning windows maybe.

that would be brown reveals.
 
aah, i can see the mark above the window as well :eek: cant think what that could be of hand.
 
the closest chips to sunflower i can see without a red highlight are monarch........take a look.
 
I dont think the monarch looks anything like it, the perm gold spar is the best match.They would of had to be doing some serious window cleaning to get marks like that. Would be interesting to obtain one of those books you have as nothing comes up on google.
 
thanks. When you said earlier about traditional methods of sand cement , and instead to use polymers,what did you mean? Were you meaning cement/render dye, is that polymer? With the colour additives do you just use normal sand cement?
 
if you use a polymer roughcasting, rendering system you dont use sand and cement!
go back into the rowebb link and look at renders and finishes.
the background colours for your chips comes ready coloured it isnt sand and cement its a polymer coating.
the colour you see on the link is the colour your finished coating is.
it does away with the need for sand and cement and oxide colourants.
 
ive had a look and asked them what the 25kg range from so i can add up what i'd need. Do you have any idea of the price of an individual bag?i'm looking at approx 90 square meters to dash.

I'd have to order some samples to as it's hard enough trying to pick a dash without adding background colours to.
 
approx 4m2 per bag 23 bags around a fiver a bag.

the merchants normally have boards hanging up with sample panels.
 
Thanks al, i'll give my builders merchant a ring in the morning and see what they have available and the colours. Would i need the same again for the scratch coat or just use sand cement for that?
 

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