Dulux Trade Diamond Crazes on Caulk

14 Oct 2008
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United Kingdom
Hi hope you can help please.

I read it somewhere else that there is a problem with Dulux Trade Diamond Matt white crazing on caulk. I have just experienced the same, just the day after painting.

I read that it is to do with how tough and perhaps inflexible Diamond is, they mentioned painting the first coat with oil based undercoat then Diamond?

Your comment and advice please.

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I don't think that it is anything to do with the paint per se. It is more likely to be the caulk.

I don't have crazing issues when using Everbuild 125 caulk but I do when using the crap Everbuild caulk sold at toolstation.

OB undercoat should work but if you dont want to have to wait hours for it to dry then use Zinsser BIN.
Thanks Opps. By OB undercoat I think it was meant that it was just brushed along the caulk fillet, but point taken with today's OB paints, that's why I am now a WB convert.
I have Zinsser 123, not BIN, which has been really great to put non-vinyl matt on vinyl silk, could I use that?

My caulk was an acrylic one, not sure now which but I do have Everbuild Everflex 175 Acrylic (1.75% flex), new tubes from TS, should I try that?

These photos hopefully show how and what is wrong. This is on a radius of caulk between a quartz worktop upstand and the wall.
Thanks again.


Hi SproutsDad

Please let me know how you get on with the 175. I haven't tried it. I used to buy the 125 from toolstation until they ditched it for the slightly more expensive but massively inferior Ever Build Caulk Once.

The Zinsser 123 may be OK, I haven't tried it though (happy with BIN thus far).

When I use a caulk other than 125, I normally wait a day or two before overcoating with emulsion. If in a hurry I apply BIN first.
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Thanks again.
I actually think that it was Once caulk that I used in this instance, should have kept the empty cartridge.
I'll follow your advice but as you can see in the photos, this isn't a few hairline cracks, it is properly crazed and broken all over the caulk area.

I called the Dulux advice line and was told that Diamond, because of its 'special' formula can craze, not bind to caulk and that a good in-between coat/binder is Dulux Soft Sheen. I happen to have a tin of that used recently, I'll try it on a test run area of upstand to wall. They said likewise that OB undercoat could take a week or more to dry fully.

So I'll try that and get back to you.

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Hi Opps and anyone else who can help with this crazing issue with Diamond on caulk?

There doesn't seem to be a simple solution although Dulux acknowledge that there is a problem, but don’t give any hope of an improved product in future. Their helpline suggests a barrier coat of Soft Sheen on the caulk, other articles say oil based undercoat (long drying time), then the Diamond on top.

I can’t see that this would be acceptable for such an otherwise excellent and popular paint with decorators using it all the time!?

Caulking has always been part of the final prep before painting, straightforward. Now with Diamond it becomes a real pain having to coat every bit of caulk with this sealer / in-between paint – the corner joints of ceilings, skirting, architrave, doorways and window reveals etc. – every corner potentially. This introduces another time consuming step in the process.

Any thoughts please?
Using the Dulux Soft Sheen that Dulux helpline advised seems to work. There has been no further crazing using it under the Dulux Trade Diamond matt.
However, I don't know if it would have been the same using any other barrier between caulk and Diamond, not soft sheen specifically?
Would it have been the same result with Zinsser 123 or BIN, probably?

But what a pavlova! - do decorators really have to go though that extra stage of protecting every caulk radius? And what a pain, still it's better than crazed paint everywhere.

Of course, wouldn't it be better if Dulux could instead revise their paint formula so that this rather tedious workaround isn't necessary?
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