Although I have often read on here about cracking problems when using matt emulsion over silk and that using a soft sheen coat then matt solves the problem, I have never had this problem myself (at least not that I am aware of) and have used non vinyl and vinyl over silk. My questions are what type of matt seems to cause the problem - vinyl or non vinyl (or both.?) How soon after painting does the problem appear?. What sort of cracking have you had - crocodile skin type or other?
Never had a problem with this either. Some of the stuff I read on this forum leaves me a bit puzzled e.g mist coats on lining paper for example, whats that all about.
Never had the problem meself,nor has my mate, however , did a staircase last year where the flat,unlined,walls were really shiny, so I didn't want any problems, so.. washed and flatted a bit, then gave a first coat of some smooth stormshield I had left over, which bonded real good.
It can happen. It is a result of an unlucky combo of certain silks & certain matts. It doesn't depend on whether the paints are acrylic or vinyl but on the indivdual formulation. Matt paints tend to be relatively inflexible. Silks are more flexible. So, put something inflexible over something that moves can cause cracking. When it happens it looks kind of like a crackle glaze. The cracking happens pretty much as the paint dries. The problem is caused by silk paints absorbing a little water from the matt you're applying on top. This causes them to shift around (microscopic level). This causes the matt to crack, but adhesion is good & it doesn't flake. The issue can be minimised by sanding down the silk first, but this doesn't always work. The best avoidance measure I've found is to find out what the silk paint is (if you can!), then use the same brand & type on top - but in the matt.
best solution to re painting silk with matt is: rub down the walls with 120 paper. mist coat with white. 2 coats of your new matt colour. done. sorry never had this problem bertie so can't really say much
Never had a problem with this either. Some of the stuff I read on this forum leaves me a bit puzzled e.g mist coats on lining paper for example, whats that all about. Purleeeze Prep it, lets not go there again....:^O:^O:^O
Have had it happen once, and that was enough for me to follow the soft sheen route from that point forward
Asked Dulux Trade Technical help about this and have had a reply. Have asked them for answers to a couple of other questions and when I have the full answers I will post what they say
Still waiting for the reply to my other questions - maybe they are incapable of more than one answer at a time. What they said about matt over silk was that matt paint will not stick to the silk, that's why it cracks. They said that painting over the silk with soft sheen may help but they recommend removing the shine from the silk e.g by sanding before applying the matt. So what they are saying (but they don't mention it on the tin or anywhere else) is that if you use silk you are making a big problem for the future. Imagine rubbing down every silk finish room before emulsioning over the old paint. Why don't they warn people about this on the tin? Personally, I hate silk finish. It looks rubbish wherever it's used
Personally, I hate silk finish. It looks rubbish wherever it's used No probs with that quote - its nasty for sure!
ive seen it in houses but ive never had it happen to me, i just stick to matt unless the customer wants silk
Berti i have had it happen once, and that was once to many, i now always suggest that a test patch or patches are done. then if needed soft sheen is specified as a barrier. T-C
The Dulux Tech people did say that using soft sheen over the silk may work but they recommended sanding the silk before recoating as new emulsion would not stick to the silk . Now I don't claim to be a genius, but if they say that new emulsion will not stick to the silk, how can they say that using soft sheen may work? Why should soft sheen stick any better than anything else - not logical. If they say emulsion will not stick to the silk, then surely what they are saying is that, unless it's rubbed down, nothing will stick to it? Now if that's the case, surely they wouldn't expect decorating contractors who use silk for let's say a hospital or a large public building to rub down all the walls and ceilings before applying new emulsion. Also, if they say it won't stick, how come new silk seem to go over old silk without any problem? Personally, I am not sure that these tech people really know the answers and just give you a 'cover our backsides' answer. I asked them some time ago if they did UPVC window in a colour other than white and they said no. When I asked if the white could not be tinted they said it could'nt. I then asked them whether they had tried tinting it and they said no, because most people would want their windows white. And they finally agreed with me that they had said no you can't tint it but had never tried it - so they didn't really know. Now why did they not just say that in the beginning? They also told me years ago that you can't emulsion over vinyl wallpaper because the emulsion won't stick to the vinyl yet I have come across this many times and it was stuck like the proverbial Personally I think the pro decorator knows more about the product than the manufacturer
vinly's a bit hit and miss. i don't do it unless the customer is insistent. try to talk them out of it but they don't have it
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