Damaged plasterboard - Zinnser Gardz and skimming

Plastering questions and answers here please

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The Monkey
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Damaged plasterboard - Zinnser Gardz and skimming

Post by The Monkey »

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
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Damaged plasterboard - Zinnser Gardz and skimming

Post by yartin »

Did you tell Zinsser what you said when they told you not to but they did say what you told them?
The Monkey
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Damaged plasterboard - Zinnser Gardz and skimming

Post by The Monkey »

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
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Damaged plasterboard - Zinnser Gardz and skimming

Post by yartin »

Sorry, I don't know gardz. One thing I can say, Zinsser is overrated here.
ahfix
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Damaged plasterboard - Zinnser Gardz and skimming

Post by ahfix »

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

ah
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Damaged plasterboard - Zinnser Gardz and skimming

Post by ahfix »

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
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The Monkey (Tue Jul 07, 2020 10:06 pm)
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The Monkey
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Damaged plasterboard - Zinnser Gardz and skimming

Post by The Monkey »

I was thinking of Polycell finishing skim?
yartin
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Damaged plasterboard - Zinnser Gardz and skimming

Post by yartin »

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.
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The Monkey (Wed Jul 08, 2020 9:18 am)
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Damaged plasterboard - Zinnser Gardz and skimming

Post by The Monkey »

Thanks for all the replies - what would you recommend instead of the finishing skim - that link was broken.
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Damaged plasterboard - Zinnser Gardz and skimming

Post by yartin »

Do you have photos?
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Damaged plasterboard - Zinnser Gardz and skimming

Post by ahfix »

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
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