Paint under wallpaper

[Matthew Kavanagh]

Hi all,

I have bought my first house and I am taking my first steps into DIY.

I have removed the wallpaper from the walls and underneath appears to be a yellowish paint/plaster?

In some areas it is flakey and in others it appears pretty smooth. I have uploaded two pictures.

I have read that I should do a thin coat before filling to show the imperfections first.

What I want to know is. What is on the wall? And do I need to sand it all off before doing a coat, or just make it relatively smooth?

Thank you for your help and Sorry if I have broke any forum rules.

Matt

 

[footprints]

Looks like the dreaded Distemper! It was used before emulsion paint appeared more or less the same as whitewash, made up of powered chalk with a size glue to bind it. Trouble is after many years the size breaks down and you are left with a layer of chalk. wipe over with a wet rag if it starts to come off the whole lot needs stripping, elbow grease and sugar soap! It is possible the wallpaper paste residue may have sealed it to some extent. A stabilizer product may save you a lot of work this sort of thing.
https://www.rustins.ltd/rustins/our-products/speciality-paints/quick-dry-stabilising-solution

 

[opps]

How old is the property?

As footprints says, warm water will "dilute" distemper. Looking at the images it looks more like emulsion to me though.

Most of the houses that i work in are Victorian but a few of the houses that I have worked in that were built in the 80's had vinyl silk under the existing wallpaper which blistered like the ones in your photos. Silk is pretty much impossible to sand flat- it just clogs the sandpaper. I normally apply a mist coat over the bare plaster patches, followed by a full fat matt emulsion. I then sand that with 150 grit paper and fill as required. I then line the walls with 1000 grade paper.

The lining paper will help you achieve a higher quality of finish. The problem with just using filler is that the filler will be softer than the paint. When you sand the filler so will see a slight dip where the filler and paint meet. That said, if you find it acceptable it will save you extra time required to line the walls.

Some fillers will grin when you paint over them (ie. the paint may be slightly darker when you paint). Toupret are one of the better brands. You can use their interior powder fillers that you mix with water but the dust created when sanding sticks to everything. I often use their RedLite filler instead of the power fillers. It is more expensive but any dust not caught by my dust extractor and sander is easily hoovered up.

 

[Matthew Kavanagh]

Hi everyone thank you for your help.

The property was built in 1956, only one person has lived in the property prior to us.

The wall seems abit Sticky so abit worried about applying anything. When the product on the walls gets wet it turns into really think paste and is equally as hard to remove.

Thank you matt.

 

[opps]

It does sound like it could be distemper as footprints suggested. I wouldn't expect it to be sticky though. The stickiness may just be the old wallpaper paste, it should wash off with warm soapy water. Does the paint become soft/paste like or not when wet?

 

[Matthew Kavanagh]

Hi,

I have given it a scrub with hot soapy water for 5 minutes and it started to come off a bit.you can see the result in the 1st picture.

Yes, the paint does go to a paste when wet, so I have to give it quite a hard scrub for it to come off.

In the second picture you can see from left to right, the yellow paint, the paint when wet is the darker section and the grey on the right is the plaster.

Thanks for all the help.

Matthew

 

[footprints]

A steamer will work but be very careful not to "pop" the plaster. Traditional way is sugar soap solution and a scrub with a sponge.

 

[Tigercubrider]

I had 2 rooms about 15 feet square and ended up sanding the whole lot off. I did try washing/soaking but it was a nightmare.
I used a sander on a dust extractor.
A powered one btw but someone on here recommended
https://www.toolstation.com/mirka-dust-extraction-handy-sander-kit/p86220
And I intend to give it a go.

 

[Matthew Kavanagh]

Thank you for all the advice

 

[opps]

Thanks for clarifying that it is distemper.

Other than the advice offered above, you can roll a coat of waperpaste over it. The paste dries far more slowly than water alone. One it has softened the distemper you scrape it off.

Tigercubrider's suggestion of using a sander connected to a dust extractor is the least messy.