cracking paint

[gas01]

I moved into a house and painted over this dark blue colour with white emulsion then painted over that with 2 coats of a peach colour.

Used a roller for all walls.

I noticed after drying that if you look closely at the wall they are full of a network full of cracks like the london underground !!!

If i paint again, what should I do first to get rid of these hairline cracks and why might I have them.

Many thanks
G

 

[gcol]

Sounds like your problem is due to painting over a vinyl silk surface with matt. Did you rub the walls down with wet and dry before you painted? I'd prime it and then have another bash at painting it with the peach colour.
That's just my opinion..... you might want to wait for the opinion of a "time served" tosher before proceeding.

 

[Nestor_Kelebay]

Take some regular masking tape and stick it to that cracked paint in an inconspicuous spot, and then pull it off. See if the white emulsion paint pulls off the blue paint under it, or the blue paint pulls off of whatever is under the blue paint. You'll be able to tell by the color of the underside of whatever is still sticking to the tape. Post your results.

Most people aren't aware of it, but emulsion paints can develop a fair bit of tension in them as they form a film, and this tension can be sufficient to pull an underlying paint off the wall if it's not sticking well. Perhaps that might explain the formation of these hairline cracks.

 

[gcol]

Are we talking about cracks as in actual gaps in the paint or are we talking about the paint puckering in raised ridges?

 

[gas01]

Thanks guys, I did the tape on wall and pulled it off, but nothing came off.
Me and my dad did paint the room as quick as poss as we were moving in so we didn't pay a lot of attention to detail.

Now I have time I'm going to re-decorate. So to start from scratch, before selecting a new paint colour - probably peachy again, but matt coz the wall are not that good and I don't really want the expense of a plasterer to make them smooth. Matt is meant to be better so I've been told as it doesn't show the uneven walls.

So what preperation should I use. Rub down the walls with what ?

This time I'll spend plenty of time on the room.

The colour before we painted was a blue and we put white over it then the peach. The cracks show blue underneath. So maybe it is that the blue was silk and I used matt ? Which I'll need to do again.

Thanks
G

 

[gcol]

If the cracks are only very narrow/thin I think I'd be inclined to try one more top coat of your chosen colour. You could try a test area if you're not sure.

 

[Nestor_Kelebay]

I really don't understand what caused the primer or the peach paint to crack if the blue paint is adhering well to the wall and the primer and peach paint are both adhering well to the blue paint.

However, use some nail polish remover to see if the blue paint is emulsion or oil based. Emulsion paint will be rapidly dissolved into nail polish remover, and therefore rapidly discolor any tissue damp with nail polish remover the same color as the paint.

If it's an oil based paint, I'd prime with a sticky primer like Zinsser's Bullseye 123 rather than what you may have been using. Bullseye 123 sticks much better to smooth surfaces than other primers.

However, 123 has lousy hide, so it may require top coating with another primer, or going with another coat of peach paint to hide the blue substrate.

Inspect carefully after painting over those hairline cracks. If they re-appear, there's something going on that should be investigated before you go any further.

 

[gcol]

Just out of interest I typed in "nestor kelebay 123" into google just to see what popped up. Nestor you do get about the diy forums don't you?
You got shares in Bullseye 123 or what?

 

[Zampa]

Time served tosher (careful with the spelling!) here........

Right then..my first thought were the same as Gcols..as some vinyl silks do have quite a sheen on them..when you use a vinyl matt over the top you can get a crazed effect because of the way it dries..the dry film is a lot more brittle than that of vinyl silk because pigment to binder ratio...silk is more 'elastic' ...and doesnt tend to have the same problems when you use it to overcoat old vinyl silk.

Its either that or the wall you painted was greasy before hand thus causing a lack of adhesion.

But my gut feeling is that its the first option...(so well done Gcol...your guesswork is improving on a weekly basis mate!)

Wet and drying the walls would have been a good idea...but do i get the impression that the room has been finished?....if so, no amount of making good and priming will help now because all the action is going on between the original coating and the one you have put on...give it a couple more coats and keep your fingers crossed...it should be ok.

I tried the google trick too..(thats two of us on here obviously with too much time on our hands!)...interesting...I reckon our mate Nessy is being paid to promote Bullseye....hope you get the same rate as I get for slinging Dulux's name around Ness...

Tried Zampa yet?...youl never get it...