Old paint colour still showing underneath after 3 coats.

[shopkeeper]

I have spent the last 2 months of my spare time (evening and weekends) removing wallpaper and preparing the walls underneath by filling and sanding the holes and cracks that were there. I also spent additional time making sure the walls were clean and spotless as I could achieve, even sanding the walls to achieve a smooth finish in preparation to applying paint.

intially after removing the wallpaper, I noticed that the walls had been previously painted ( a different colour in each of the rooms, light green, blues and pink etc). I applied a coat of white matt paint with a roller to the wall in the lounge ,which had been previoulsy painted a light shade of green. I wasn't too worried that the paint seemed to be going on a little thin and I could still see a lot of the green paint underneath but was somewhat concerned that there was splotches where the matt paint seemed to be sticking much more and causing spots of it to appear in places on the wall.

Today I applied a second coat of the white matt paint and it has hardly made any difference! I can still see a far amount of the previous green paint and if anything it has made the splotches that appeared from the previous coat even more apparent.

Please help with suggestions on what I could do. I am beginning to despair at the thought of having wasted weeks and being left with a horrible finish.

 

[TheDec]

When you stripped the wallpaper you should have washed the walls with sugar soap to remove any paste reidue, what emulsion are you using and what do you mean by splotches. Also are you thinning your paint and if so by how much.

Dec

 

[WalksWithTurkeys]

I am an ignoramus, but I have almost finished painting all of the walls in my house, which were originally wall papered, and vile.

Are you sure you removed all wall paper paste from the walls? If not then painting would reactivate it. Also, what is the surface of the old paint like? It might be too smooth.

After I removed the wallpaper I was left with porous powdery walls with wall paper paste soaked in. So I first applied a coat of Zinsser Gardz. That sealed the wall and prepared it for top coats. Then I applied acrylic emulsion with a microfibre roller.

You could try a sealer of some kind. But first wait for answers from more experienced people.

 

[shopkeeper]

When you stripped the wallpaper you should have washed the walls with sugar soap to remove any paste reidue, what emulsion are you using and what do you mean by splotches. Also are you thinning your paint and if so by how much.

Dec

Forgot to mention that I washed the walls with sugar soap and then rinsed them down with clean water after removing the wall paper, filling and sanding.

I'm using Dulux Matt White paint :http://www.collierspaintshop.co.uk/dulux-matt-emulsion-pure-brilliant-white-10ltr-4314-p.asp

I've uploaded a couple of images to show the 'splotches'. Basically small patchs where the paint has taken to the wall more than its surrounding.
You can also perhaps notice the lime green paint underneath still showing through.

//www.diynot.com/network/shopkeeper/albums/10258/38691
//www.diynot.com/network/shopkeeper/albums/10258/38692

I've also uploaded a photo of the prepared walls in the stairs that I havent yet painted over:

//www.diynot.com/network/shopkeeper/albums/10258/38696

The photo isn't very clear, but the existing paint is a light yellow colour.

 

[shopkeeper]

Are you sure you removed all wall paper paste from the walls? If not then painting would reactivate it. Also, what is the surface of the old paint like? It might be too smooth.

I think I did remove all the wall paper paste from the walls. Hard to say. I washed the walls down throughly with sugar soap and then rinsed. How would I check if there was no residue of paste left from the wallpaper?

I think your right about the surface being too smooth. I did sand it down quite a bit. You can run your hands over it and it hardly has any texture. Would that effect how the paint adheres, even after a couple of coats of new paint already being applied?

After I removed the wallpaper I was left with porous powdery walls with wall paper paste soaked in. So I first applied a coat of Zinsser Gardz. That sealed the wall and prepared it for top coats. Then I applied acrylic emulsion with a microfibre roller.

You could try a sealer of some kind.

Did you use a matt paint on your walls? Thanks for the information on the preparation you did and advice on the sealer. What kind would you recommend?

 

[JohnD]

to my eye, those patches look like where filler has been used.

Did you apply a mist coat thinned with water to kill the absorbency of bare plaster or fillers?

I find that, to remove old paste residue, it is better to use plenty of warm water, and a broad metal scraper. The paste comes off as slime which you wipe off the scraper on your sleeve or a bit of kitchen roll.

any trace of old paste will prevent the new emulsion touching the wall.

Plaster is naturally absorbent, so unless the plasterer has polished it like a mirror (they sometimes do that if they've fallen out with the decorator) your mist coat will soak in and give a suitable surface for the unthinned paint.

 

[TheDec]

It could be just a problem with application, difficult to say really, you could apply a thinned oil based undercoat over the areas, or indeed to the entire area before you apply anymore emulsion. That would seal the surface and should offer you an even coverage.

Dec

 

[WalksWithTurkeys]

Are you sure you removed all wall paper paste from the walls? If not then painting would reactivate it. Also, what is the surface of the old paint like? It might be too smooth.

I think I did remove all the wall paper paste from the walls. Hard to say. I washed the walls down throughly with sugar soap and then rinsed. How would I check if there was no residue of paste left from the wallpaper?

I think your right about the surface being too smooth. I did sand it down quite a bit. You can run your hands over it and it hardly has any texture. Would that effect how the paint adheres, even after a couple of coats of new paint already being applied?

After I removed the wallpaper I was left with porous powdery walls with wall paper paste soaked in. So I first applied a coat of Zinsser Gardz. That sealed the wall and prepared it for top coats. Then I applied acrylic emulsion with a microfibre roller.

You could try a sealer of some kind.

Did you use a matt paint on your walls? Thanks for the information on the preparation you did and advice on the sealer. What kind would you recommend?

I used Dulux Endurance matt, which is a tough acrylic paint. I first applied Zinsser Gardz which is an acrylic sealer. I found that the first coat on top of Gardz was rather patchy.

No idea how to check for wall paper paste still on the wall. Being a beginner, I did not want to take any chances, which is why I applied Gardz. It made sure the wall would be okay for the paint, and it helped seal the walls which had lots of tiny holes and porosity. I did not seal in side a cupboard, and the painted surface is nowhere as good, as the paint soaked into the plaster, leaving it looking porous, rather than sitting on top.

If you have a hidden area of wall such as in a cupboard, then you can experiment. Apply more coats as you are doing, and see if it covers better.

What paint are you using? If it is cheap, then it will be watery anyway, and diluting down for the mist coat (I assume you did that) will make it worse. The first mist coat is always patchy. It pays to buy decent paint. I think Homebase or B&Q have an offer on paint at the moment. Stick to Dulux, Crown, Leyland i.e. big names, not own brand.