Emulsion on wall cracked. Repainted with BIN, cracked again

[JaySab]

Hi,

I'm new here so go easy one me

We recently bought our first property and have started decorating. Our bedroom walls were painted with something that has a slight sheen to it. Error #1 - we painted over it with matt emulsion. It cracked as it dried, which led us on a search around various DIY sites including this one.

The advice often given out is to sand the walls down, clean, rinse and use a primer/sealer. This is what we did:

Sand the walls with 100g sandpaper (not completely back to the original paint, but enough sanding that I was pulling dry paint out of my nostrils the next day)
Clean the walls with sugar soap
Rinse the walls with water
The next day we coated the walls with Zinsser B-I-N

The next step was to be to let it dry for three days and then paint with emulsion.

Unfortunately, some of the B-I-N has started to crack. it's not as pronounced as it was with the emulsion, and weirdly, it's only in a few places. One wall is worse than the others for eg. I've attached a (not very good) picture.

I contacted Zinsser and they have suggested I sand right back down and start again.

I hope this isn't our only option as this process has now taken well over a week and been more costly than I expected. Is it worth trying a second coat of B-I-N? Or even now painting with emulsion?

Thanks.

Untitled

• JaySab
• 15 Apr 2015
• 1

 

[joe-90]

You wanted Zinsser Gardz.

 

[JaySab]

Thanks for the reply.

I've read lots of recommendations about what to use in the case of emulsion cracking over existing paint and from the Zinsser range, I've seen all of these recommended:

B-I-N
Bullseye 123
Gardz

The Zinsser customer service person who responded to my email has said that B-I-N is fine for this job.

So I don't think the choice of primer is the issue.

 

[dcdec]

Having just been looking at their site i reckon you could try two or three coats of bedec interior flex

 

[joe-90]

The only way to really sort it is to sand it back. You could try Wickes lightweight filler. It's brilliant for fine surface cracks, then a couple of thicker coats of Wickes trade contact emulsion. Nothing else will work.

 

[JaySab]

Thanks for the replies.

The thing thats's worrying me about sanding again is, well, we've done that. How can I prevent this from happening again?

 

[JaySab]

So I've resigned myself to the fact that I need to sand back and prime again. I'd like to make sure it's done right this time. Would someone be able to help with the following questions?

How far back do I need to sand? We've now got: the original shiny paint (and whatever is underneath that), some remnants of emulsion, Zinsser B-I-N.

Is 100g sandpaper the right choice?

There are entire sections of the walls which haven't cracked. In fact, one entire wall is fine. The texture isn't great though, if I'm honest. The primer looks sort of pitted.

Can I leave these bits?

If so, should I sand these primed areas lightly? And should I wash them down? (I imagine they'll get dust on them when I sand the other bits)

If I try a different primer (say, Zinsser 123) on the bits I'm going to sand back, will these turn out a different colour to the bits covered in B-I-N when we paint?

Thanks. I could really do with not having to go through this a fourth time