After Removing Artex from Walls...

[Hipokondriak]

Lost DIYer has a problem with a wall in the front room. The south facing (ish) front room wall has recently had a thick coat of artex and paint removed, back to existing plaster.

The hollows and holes have been filled in, where required, and the entire wall has been washed down with a strong solution of sugar saop.

Left to dry overnight.

The next morning, the entire wall was covered in a fine dust like mould.

Wall washed again with strong Sugar Soap and left to dry.

When dry for several hours, applied first coat of tesco branded matt white emulsion. Straight from the tub. With hindsight not the best plan -should of diluted it. But, it looked good and dried nice.

About 2-3 hours later, applied second coat, and this is where the fun begins. After about ten minutes, the paint starts to develop what looks like patches of eggshell-like bubbling that spreads over most of the wall and no amount of overpainting will stop it. after about 30 minutes it is peeling off the wall as you watch it dry. As I use the roller to overpaint, it is sticking to the roller and peeling off the wall in strips.

Took it back to bare plaster and washed wall again with sugar saop, and re-applied tesco's best matt emulsion and it looked good when dry. Smooth and flat with no blemishes. faint shadows but no real problem areas. after about 2-3 hours, applied second coat and then it began again, but in smaller areas, not the whole wall this time.

An area under the window , the size of the windoe aperature from windowsill to floor is affected and a small area to the right of the window at head heght about the size of a coconut.

Any advice or suggestions. I've got three days to finish this job, before I go back to my regular job of pi**ing off the car drivers on the M25, in my 44 ton truck.

 

[malshep]

Hipo,

Seems like the experts are having the day off - so I guess I’ll jump in and give it a go.

Think of your problem in these terms: what you’re trying to achieve is
substrate +paintlayer1 +paintlayer2

When you put paintlayer2 on top of paintlayer1 the moisture from paintlayer2 re-wets paintlayer1 and could well cause it to expand a bit. So if you’ve got poor adhesion between substrate and paintlayer1, then the time it will show up is when you put on paintlayer2. Paintlayer2 is the danger point - if you ever get to paintlayer3 you probably won’t have a problem. The problem then is getting paintlayer1 to stick to the substrate.

The dust you are seeing is dried sugar soap - not good. Sugar soap is a detergent for getting rid of grease, oils, fingerprints etc. If there were any grease,fingerprints etc they would have been on the artex which you’ve already stripped off. You never needed a detergent - so QUIT using sugar soap. If you’ve got any on at the minute either thoroughly rinse it off or if already dry, use a brush, then fine sandpaper, then brush, then tack-rag etc etc. Do whatever is necessary to get to a dry dust-free MATT surface.

Assuming the substrate is porous plaster/filler then apply a mist coat (diluted emulsion) as paintlayer1. If you’re really scared you could always put BIN on as paintlayer2 - it isn’t water based so is less likely to drag paintlayer1 off the walls. But hopefully so long as you’ve got to a dust-free matt substrate to work with you’ll be OK putting undiluted emulsion as paintlayer2 and paintlayer1 should stay put.

 

[opps]

Hi Hippo

Malshep has given you sage advice.

I wouldn't be too worried about the sugar soap reside- it doesn't contain any silicates. If you are concerned then vacuum it off with a brush attachment on your hoover.

I too would have used Zinnser BIN as it is shellac based and will not reactivate the emulsion. If you do buy some then also get some household cleaning amonia, about a quid. It is the best way of cleaning the brushes after and you can pour it down the sink after (or leave the waste in a pot- the ammonia will evaporate off in a day or two), the only other cleaning agent is meths.

 

[Hipokondriak]

We just got your posts at about 9pm tonight but....
a kind friend had suggested this to us earlier this morning and hinted at something called "distemper" which is a bad thing.

all day I have been washing down with plain old water and replacing the supply as it became sludged up with the residue from the sugar saop.

I now have a clean and dry wall. I have had to touch up a few places where the polyfilla had come off, but have now called it a night and will be rubbing down in the morning. another coat of PVA at 5 parts water to one part PVA and leaving it to dry before the initial coat of base paint at 75% solution of paint to water, although I think it unnecessary after PVA'ing the wall.

Advice on the last bit?

 

[opps]

DO NOT pva the wall. Your emulsion will slip and take longer to dry, just thin the emulsion.

Distemper is an old calcium base paint that one occasionally still finds in older homes- typically on ceilings. It is slightly trendy in parts of Fulham. Personally I think that they are silly and impractical and hate using them.

http://www.buildingconservation.com/articles/lwdistempers/lwdistempers.htm

Ideally distemper has to be washed off but you say that the wall was back to plaster.

Sometimes the chalky marks can be effervescence but this seems unlikely as you didn't see anything until you washed the wall. This would have required alkali resistant primer or Owatrol EB.

I am concerned about the filler coming off, do you mean that the paint underneath bubbled and forced the filler off? If so then get some Zinnser BIN shellac/alcohol paint

 

[Hipokondriak]

this has been mentioned on several posts, what is shellac or BIN?

>edit<

Found it at homebase, Romford.

That stuff is expensive

>edit<

As we were washing the wall down with water, the polyfilla came away 'cos we were too heavy handed with the brushes and rags.

The second layer of paint was peeling off onto the roller as the second layer was applied, and the remaining paint started to blister and bubble then crack as it dried.

 

[opps]

BIN is made from shellac suspended in alcohol.

Shellac is harvested from shellac beetles, they excrete it (lac). Hence the cost.

It has been used for years and is also used to cover tablets/pills and things like apples at one stage (I think they use a different type of wax now).

It has been recommended to you because it is not waterbased and so will stop the emulsion from reactivating and peeling. You could use oil based paints but shellac is recoatable in under an hour and the smell will go much much faster.

It is much thinner than undercoat so it goes quite far.

From a materials cost your cheapest option is to apply more emulsion and then scrape it all off but the BIN route is much faster/cleaner and cheaper from a labour point of view

 

[Hipokondriak]

Just got back from Wilkinsons where I was advised to buy basecoat wall coating. This is supposedly as good as Shellac, but at a fraction of the cost.

I will be giving it a go shortly and will post my verdict about it later.

 

[opps]

Just got back from Wilkinsons where I was advised to buy basecoat wall coating. This is supposedly as good as Shellac, but at a fraction of the cost.

I will be giving it a go shortly and will post my verdict about it later.

So the good folks at Wilkinson recommended a waterbased product to cure problems with a waterbased paint...

http://www.wilkinsonplus.com/Wood+M...OJW+4DXA+DtPwgpwYw2+N8guIqpjVhSP sgZMqEe3cw==

With regard to them suggesting that it is as good as shellac that is like comparing a pc to a tv- they might have some attribute overlap but they are quite different

BTW

BIN=12m2/l coverage, whereas your stuff is about 6.8m2/l, so although BIN is expensive it would have only cost about double what you have just paid.

 

[Hipokondriak]

Well it worked

First coat, watered down 75% paint & 25% water, hand brush painted, left for about 5 hours then a second coat, at full strength, and it has gone on a treat.

Currently no stripping, peeling, or bubbling.

The old guy at wilko, was a professional painter but gave up due to ill health, seemed to be very knowledgeable and his advice was sound.

Even his advice was to use the shellac, but they didn't have any in and this was the next best thing. Or I could wait until monday, when the delivery comes in.

Anyway, it seems to have worked this time.

 

[opps]

The old guy at wilko, was a professional painter but gave up due to ill health, seemed to be very knowledgeable and his advice was sound.

Even his advice was to use the shellac, but they didn't have any in and this was the next best thing. Or I could wait until monday, when the delivery comes in.

Anyway, it seems to have worked this time.

My apologies to the Wilko fellow, I had assumed that he was your typical shed employee.

Glad it worked for you.

Could somebody pass me a slice of humble pie please...

 

[Hipokondriak]

Job now done. 3 coats of white emulsion on the wall and no peeling/stripping.

Unfortunately for me, though, I am putting the stuff on the wall and I am thinking - this matt emulsion is a bit shiny, maybe it will dry matt. No it don't.

A quick check on the pot and it says on the printed label "Trade Emulsion Matt 10 litre".

The following day, I peel the label off, and find, printed directly onto the plastic container, is the legend "Trade Emulsion Silk 10 litre"

A quick call to B&Q, a return to the store to show them the pot and a nice new pot of MATT emulsion is now sitting in my front room. Plus a £10.00 voucher in my wallet.