We are trying to repaint the hallway in our house, which was built in 1957. I thought this would be fairly simple and straightforward, but after washing the wall down to prepare for painting, we soon realized with horror it was actually painted wallpaper (bubbles appeared when it was wetted down.) So we regrouped and stripped the wallpaper, which thankfully came off without too much of an ordeal. Underneath the wallpaper is a layer of brown paint. We washed the wall down quite well with DIF and then with an all purpose cleaner. There is no visable wallpaper glue left. I now know we should have applied a primer at this stage, but at the time we thought the wall was clean and sealed by the previous paint layer. So we started repainting, first just around the edges, so we could roll the middle bits. The new paint color is a cream color so we decided to do 3 coats to cover the brown. The first two coats (still just around the edges) went on fine. On the third coat, in random spots, tiny bubbles appeared almost immediately after the third coat was applied. If you pop the bubbles, you find that the paint is coming up from the bottom most layer and pops back to the brown paint. In addition, in these areas the paint seems to just not be adhering well at all and peels off back to the brown very easily.

Several people have told us that the most likely problem is residual wallpaper paste making the paint not stick and that we need a layer of primer to seal the paste away from the paint.

So my questions are -
Is residual wallpaper glue the most likely cause, or could it be anything else?

Why did the bubbles not appear until the third coat?

At this point, what do we do? .....do we have to get the paint we've already put on back off the wall..before applying a primer...if so, how? .....stripper?....sander?

and finally, since I have no idea when this brown paint was put on, do I need to be concerned about lead, if sanding is necessary?

other pertinent details: pretty sure the walls are sheet rock rather than plaster.
...seems to be a lighter brown layer of paint under the darker brown, but that seems to be all.
..... the bubbley patches are more often along the ceiling edge of the wall than along the baseboards.



Thanks for any help,
Shanc21

 

Most likely its glue residue.
Try to prime it with an oil or alkyd based primer, or a DRC like Zinsser's Gardz.
Hopefully, this will lock down the surface so it can be painted successfully.

 

As far as lead goes, is the paint a deep chocolaty brown?
The last time that was in style was the 70's. I wouldn't worry too much, because they stopped putting lead in paint in the late 50's, but if you're really worried, go to Home Depot and you can actually get a test kit.

 

I don't mean to be picky, but this information is incorrect
Since lead is a health hazzard, please excuse my correction

Lead was used in paint until the '80s
If you are scraping, sanding, or removing paint from the mid-'80s or earlier, you may be releasing lead dust

 

If I'm not mistaken lead was not used in residential paint after the early 70's, by the late 70's it wasn't very common in industrial paint. Automotive paint was the last to quit using lead - either late 80's or early 90's.

 

The Federal EPA line is:

"Since the 1980's, EPA and its federal partners have phased out lead in gasoline, reduced lead in drinking water, reduced lead in industrial air pollution, and banned or limited lead used in consumer products, including residential paint."

"Many houses and apartments built before 1978 have paint that contains lead (called lead-based paint). Lead from paint, chips, and dust can pose serious health hazards if not taken care of properly."

Though we use '78 as a cutoff around here for residential, we consider up to '82 iffy
Any customer that says the last time it was painted was "....uh...maybe 1980" we tend to consider it's got lead until we're sure

Commercial pretty much anything in the '80s we consider it lead unless proven otherwise