Prepping old walls for paint

[disco_monkey79]

Hi

I have stripped off the wallpaper, and the walls (plastered in December '81 according to the pencilled signature!) are in rather good nick, so I want to paint straight on to them, instead of lining.

What is the best prep for getting off the old paste residue etc? Sugar soap? A light rub-down?

Also, can anyone recommend a good matt emulsion for old well-dried plaster?

Lastly, I have used regular gloss as a stain blocker in the past. Is there any benefit to buying actual stain blocker, or should I continue to use my gloss?

Many thanks

 

[SammyQ]

"What is the best prep for getting off the old paste residue etc? Sugar soap? A light rub-down?te residue etc? Sugar soap? A light rub-down?"

IME, the latter. The old stuff acts as wall size. Sugar soap is a much over-rated reconmendation anyway, but removing the old paste residue by other means might leave a horribly porous wall and thereby a patchy paint uptake, necessitating more coats.

Sam

 

[Rorschach]

Hot soapy water and go over it several times. Then a coat of zinsser gardz. Fill and sand before the gardz.

 

[disco_monkey79]

Thanks both

 

[SammyQ]

I thought "gardz" was a film with the excellent Brendan Gleason...

Ssm

 

[Bm101]

If you have a steamer and a decent filler blade, by that i mean a fine condition bendy scraper (in woodworking terms think a 1mm scraper type thickness) and a good sense of timing it's pretty easy to just heat the glue up and scrape it off. Have some rags to hand to wipe your scraper and importantly, keep up the momentum. You need to keep that balance between heat and moisture to a minimum. Use long sweeps. Think plastering motion. Try not to become localised because time is your enemy here.
Honestly on sound plaster, look at doing a metre square ish and then the next in a few moments once you get the Temps and rhythm right.
Afterwards open all windows turn up the heating etc. Next day you are miscoating. Fine filling. Toupret if you want the best. Miscoat the filler after a quick rub. Then 1 or 2 coats of a decent paint. Not entering that debate.
I would recommend getting a decent roller set. I have a crown trade one and it miles away from them carppy 2 pound ones from bnq. Different world.
Ok
Sorry been on decorating duty too lately. :roll:

 

[lurker]

All the internal walls in my house are painted. They were all done by a brilliant turner who used to be a forum member, who at that time was a professional decorator. I truly detest decorating. This was about ten years ago.

BUT
They are covered in a top quality liner paper and then emulsioned with what ever tint her majesty decided. Once a year I spend maybe five minutes per room going over the marks with a four inch foam roller. Whole place should last another ten years before anything else needs doing.

 

[Rich C]

I stripped paper from one room when we moved in a year ago. The plaster was shot so I ended up getting it skimmed. If it's in good nick I'd go with normal bare plaster routine - mist coat (I actually used screwfix bare plaster paint) then a couple of top coats. It's fine a year later.

I probably wouldn't use gloss as a primer as it's not as easy to get emulsion to overcoat it.

 

[--Tom--]

Moved into ours and stripped the wallpaper, had bare plaster from when the house was built in the 30s. Scrubbing brush and hot sugar soapy water cleaned them. Minor filling followed by leyland trade Matt emulsion. First coat watered down, second coat neat. Can’t remember the name of the filler but it was a trade one that worked a treat. Only sanded down the filled areas, as the plastered finish was different to modern plaster as it contained quite coarse sand that if you started rubbing down would need filling to make smooth again.

Extension is being plastered at the moment so will be on it with the same approach (without the filling) over the next few weeks as it dries

 

[HappyHacker]

Just to add a bit of variety. A friend removed wallpaper, mostly, from our hall while we on holiday. The hall is a funny shape and due to being a bungalow is quite long. Part of it is relatively new, 20 years, the rest is 70 years. Some of the plaster is poor and all has been marked by the wallpaper removal.

I have sanded it all using a drywall sander (Aldi) and a ROS. There was some paste left on the wall making it rough which has been removed by sanding. Ceiling is not brilliant either this has been sanded as well

Filling using mainly Easyfill then sanded. Mist coat of emulsion then two coats of emulsion gave a good result although I still have part of it to do. All done with a decent roller.

I did consider getting it skimmed but would have been very messy and difficult given 10 doors and need to remove carpet, skirting and architrave. Also considered lining paper but my papering skills are worse than my plastering and that is not good.

I also need to repaint most of the doors as when last done I did a good job using oil based gloss but it has all gone yellow. At the time I painted the formulation had changed but they had not put the yellowing warning on the cans. I have found it impossible to get a similar level of finish using water based paints, I have tried four different types following the recommendations for water based paints and the brush strokes are always visible. I may have to try spraying them but that may be another rabbit hole.

 

[Rich C]

We left the carpets down while the room was being skimmed and they're fine. As long as you get some dust sheets down it shouldn't be an issue. The plasterers skimmed to the skirtings (which were left on) so no need to remove them either. All I removed was the radiator and door.
In my case the plaster had fine cracks everywhere and in a few places chunks had blown. It's original 30s plaster which probably doesn't help. The plasterers did the whole lot in a day which was definitely way quicker than I could have tided it up with filler.

I think the only way to get a decent non-yellowing finish on doors is with water based gloss. Spraying will definitely give a good finish, but it's a bit awkward if you don't have somewhere to spray. Alternatively, there are various brushes designed for water based gloss which should give good results with no brush marks. You don't want to use a cheap brush you grabbed from b&q for a good finish.

 

[disco_monkey79]

Thanks all - that's my weekend looking paint-y

 

[Rorschach]

Something to bear in mind that not everyone thinks of. When painting and decorating the biggest cost is not paint, it's time.

Get the prep wrong or use poor products and you need to paint again, then you have cost yourself far more money overall than doing it right and doing it once. I think P&D is probably the main area of DIY where this is the case.

The reason I mentioned for example using Gardz is that if you miss any areas of paste or don't have any problem areas of plaster, this will protect you. A small can of it is not expensive compared to the cost of having to scrap, sand and start again.

 

[Old.bodger]

Best emulsion EVER Caparol Amphibolin.

As mentioned above, water based gloss is tricky to get nice finish, try Caparol Haftprimer Adhesion, High Opacity Primer/Undercoat and gloss, applied with 5mm pile rollers by ‘two fussy blokes’.

The difference is unbelievable, I hate painting but have to do it as part of my job. If I am doing it the finish has got to be good.

No connection except as a customer.......try........ https://paintshack.co.uk/

 

[llangatwgnedd]

For a stain blocker, oil based undercoat.
Even after I had the all the rooms re skimmed in my rental property, nicotine stains kept coming through in patches, but the oil based undercoat cured the problem.

 

[Terry - Somerset]

I have taken to using a water based satin finish for woodwork:

- it does not go yellow as oil based alternatives usually do
- gloss shows brush marks, blemishes, etc. Satin does not reflect in the same way

You could argue the latter is just evidence of a poorly prepared and finished job - but for me pragmatism wins every time!