Damaged plasterboard - Zinnser Gardz and skimming

The Monkey · Post by **The Monkey** » Tue Jul 07, 2020 3:12 pm

I must apologise that I am a complete DIY novice but would greatly appreciate some advice:

We intend to re-paint the ceiling above a shower in a house that we've owned since new-build.
Shortly after we moved in, the paint started peeling.
We got a decorator to re-decorate it a year later and it peeled again. We've left it for years.

We are now going to do it ourselves and have scraped all the paint off.
Although a lot came off easily, the decorator had put something on that made getting the paint off some patches near-impossible and I needed to use a sander.
This sanding has got the paint off but also the skim coat in places, revelaing patches of plasterboard paper (some torn) and down to what I think is gypsum( solid and white) in places. The rest of the ceiling looks like skimmed plasterboard that has never been sealed.

We intended to use Zinnser Gardz to seal the whole ceiling (damaged areas of plasterboard and the remaining unsealed plasterboard too), then apply a skim coat on the damaged areas, and then also seal this with Gardz.

I just rang Zinnser to ask a related question.
They told me you can't skim over Zinnser Gardz.
I said this is what it says you can do on the tin.
They said the tin must be wrong but would check.
They rang me back and said you could skim but only small areas.
I asked what small was and they said I had to make that decison for myself.
They also said it was for drywall and not plasterboard.
I asked what the difference was and they said I would have to google it.

I am now completely confused.

Can we skim direct onto the exposed paper layer and exposed white plaster of the damaged plasterboard / drywall or do we need to apply something like Gardz first?
Do I have plasterboard or drywall? (There is a brown paper layer and something that looks like white plaster below that)

A simple explanation for an idiot would be much appreciated.

Thanks

yartin · Post by **yartin** » Tue Jul 07, 2020 4:36 pm

Did you tell Zinsser what you said when they told you not to but they did say what you told them?

The Monkey · Post by **The Monkey** » Tue Jul 07, 2020 4:40 pm

I

yartin wrote: ↑Tue Jul 07, 2020 4:36 pm Did you tell Zinsser what you said when they told you not to but they did say what you told them?

I'm assuming this is a joke based on the format of my original question? If so, will simplifying it to "can you skim over zinnser gardz because zinnser just told me I can't" get me the answer I'm desperate for?

yartin · Post by **yartin** » Tue Jul 07, 2020 5:56 pm

Sorry, I don't know gardz. One thing I can say, Zinsser is overrated here.

ahfix · Post by **ahfix** » Tue Jul 07, 2020 7:47 pm

If you are skimming the whole area then key the surface, pva and skim with finishing plaster.

ah

ahfix · Post by **ahfix** » Tue Jul 07, 2020 7:49 pm

OK, just re-read. You are not skimming the whole area.

What product do you intend to use to skim?

Btw, dont read my last reply as pva and then paint. That is a no no.

ah

The Monkey · Post by **The Monkey** » Tue Jul 07, 2020 10:06 pm

I was thinking of Polycell finishing skim?

yartin · Post by **yartin** » Wed Jul 08, 2020 9:10 am

I won't use Polycell skim...

Is the wall nice and smooth and you don't need skimming? Assuming you can patch what you damaged with polycell fillers. If so call Dulux, explain your problem and ask if you can use https://www.dulux.co.uk/en/products/dul ... er-plaster and paint on top?

If need skimming, as @ahfix said, pva and plaster then paint.

I would use Dulux Bathroom paint.

The Monkey · Post by **The Monkey** » Wed Jul 08, 2020 10:01 am

Thanks for all the replies - what would you recommend instead of the finishing skim - that link was broken.

yartin · Post by **yartin** » Wed Jul 08, 2020 10:26 am

Do you have photos?

ahfix · Post by **ahfix** » Wed Jul 08, 2020 10:27 am

You dont say how large the damaged area is, for areas a couple of inches in area, something like https://www.screwfix.com/p/polycell-tra ... 1ltr/82124

Apply in thin layers and built up just above level and lightly sand back.

If the painted surface is flaky then a coat of this https://www.toolstation.com/zinsser-pee ... int/p44309

Read the instructions.

ah