Do i need to seal exposed plaster after dado removal?

26 May 2011
Reaction score
United Kingdom
Evening all,

We are decorating our living / dining room and today i removed all the dado rail from the walls. It came off pretty easily not ripping any large chunks of the wall off (thankfully :!:) :D

Where it came away, it has pulled off the under layer of paint, leaving wriggly lines of exposed plaster where the dado was glued on.
Do i need to 'seal' the exposed plaster before re-painting the room :?:

Firstly i will be sanding the dado section down, and filling any small chips with pollycell then re-sanding to a smooth finish.

If it does need sealing will it be a case of watered down pva glue :?:
Thanks for any answers :mrgreen:
Sponsored Links
Just sand and scrape the area and aply one coat of an oil based undercoat as a sealer, then carry on with your prep.


I've already scraped it - spent alot of time making sure i got everything possible off, the rest will sand down nicely i think :)

With applying a coat of oil based undercoat just along the line of which the dado was on, will it effect the finish of the wall once it is all painted with the emulsion?

There won't be a darker line along the old dado section will there?

Well no providing you use white, I only suggested it just in case there was any residue left from the glue, just carry on with the sanding dust off and apply one coat of thinned undercoat.

Sponsored Links
Ok thanks.

Can you recommend an undercoat branded / store brand?

Will get some bought asap and get cracking on with it

If there is no contamination from glues etc, and the plaster is bare, then you don't need oil based undercoat. You can use slightly watered down emulsion to seal the plaster, allow to dry then fill the area with fine surface filler. Once dry sand smooth and apply another light coat of the same diluted emulsion before carrying on with your chosen finish.
Yes if, always better to be safe than sorry, with regard to brand any shed brand would be fine as I said it's just a precaution.

There doesn't seem to be any glue left on the walls with close inspection, just a slight ridge of paint because of where the bare plaster is and the paint begins from above the dado line. But i plan to resolve that by sanding / fine scraping.

Also with the undercoat which is required, should i apply this before i begin to fill the chips or after the undercoat is applied?

Want to get it right first time with a flawless as poissible finish :)

In this situation I would go with the way I described previously. However, this isn't a question of which is right or wrong, just differing opinions. There is nothing wrong with either way.
If you seal the bare plaster first it will allow the filler to adhere better as the the moisture will not be immediately sucked out of it.
Is there a Glamorgan vendetta going on? Do you two know each other in the real world?
So just to clarify:

Give it a good sand down to smooth off the excess rougher parts
Undercoat it with watered down emulsion to give it some gripping power!
Fill in any chips / dents
Sand down any bumpy parts left over from filling
Give it another watered down emulsion coating

Thanks :)
I like that Joe

As I said the undercoat was suggested as a precaution, what you need to do now is by is by scraping and sanding remove that ridge then you will be ready to seal the areas,
(I will leave the choice of paint to you). Then when dry fill slightly proud of the existing paintwork, when dry lightly sand the areas smooth then apply a thinned emulsion over the filler.

You need to use a sanding block with your paper and a proper wide blade filler knife or you'll make a mess of it.
Thanks for the help Dec :)

Joe - why would i need a 'propper wide' filler knife if i am only filling in small chips in the wall :?:
I'm not needing to fill the whole width of where the dado rail was, as it came away nicely just leaving a 'lip' of paint which will be sanded down to a smooth, same level finish :?:

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links