Using Zinsser Gardz on plasterboard over old wallpaper glue?

Discussion in 'Painters' Talk' started by Alex34, Nov 1, 2018.

  1. Alex34

    Alex34 New Member

    Hello all.

    Have some questions regarding prepping and painting plasterboard for new wallpaper after removing old wallpaper.

    I came across some posts on here and other forums regarding a product called Zinsser Gardz. I was thinking of using this in the process as a sealer for any left over glue residue and hopefully to cut back on some laborious prep work.

    Scenario: My house is a new build and was a show home so it had a wallpapered wall in the lounge with mirrors and lights on it; I am getting rid of all and replacing with just wallpaper. The walls are plasterboard dot and dabbed over breeze block. There are quite a bit of screw sized holes in the wall where the mirrors were screwed to and 5 fifty-pence sized holes where wires were run for lighting... all of these holes are to be filled in.
    I have managed to remove the wallpaper, backing and most of the glue but it is quite difficult with plasterboard as you have to be delicate and not use too much water. I have experience with doing this to another wall that had a boarder. It was very laborious, involving many sessions of wet scrapes, sanding and washing of the area in-order to be able to paint. I am a bit reluctant with this wall due to the size and numerous holes in the plasterboard.
    The wall was originally skimmed then painted before the wallpaper was laid. The original coat of paint is thin and only served as a primer.

    Now my main question is regarding using Gardz. When should I apply the gardz, before or after filling the holes and sanding to an even surface? Or do I use it before and after?

    Also, what is the best paint to use before applying the wallpaper?

    Thanks for reading and for any advice you can provide.
  2. Alex34

    Alex34 New Member

    I've found, what I think is, a decent video on youtube for Zinsser Gardz on damaged drywall. I don't think the process would be any different for me. If anyone has any advice otherwise or anything to add to it could you please let me know. Thanks.

  3. DIYDave.

    DIYDave. Well-Known Member

    If your papering over wall (which I think you are), then you don’t need to remove the old paste - no point

    Repair holes with filler as per usual but, as this wall is D&D, and you have 50 pence sized holes, the filler is just gonna fall through holes and into void

    I would use bonding plaster (is the wall internal or external) as it’s cheap and almost has no depth limitation in a single application (almost)

    So dampen edge of holes with water and ram in stiff mix of bonding and smooth off. As it’s setting, flatten off again in case it bulges slightly

    Once dry, it sands easily if slightly proud of wall

    When wall repaired, size with thinned out wall paper paste, it doesn’t need painting 1st

    Your right though, if painting a wall that was previously papered, then all, and I mean all paste must be removed, otherwise as soon as the paint hits it, the paste reactivates and swells

    Other option with the above is to lightly sand wall, fill any dings then treat with Zinnser Gardz

    Your lucky that the PB wall had been painted prior to papering otherwise tricky to removed paper without destroying the wall

    Anyway, I’m diy, others may have different ideas ...... that’s the beauty of the forum :)
  4. Alex34

    Alex34 New Member

    Thanks Dave.

    Was planning on using bonding for large holes.

    I wanted to paint it because I thought that new paste would have problems adhering to the filler. Also would have less a chance or damaging the plasterboard if I wanted to remove the wallpaper in the future.
  5. Doubledecor

    Doubledecor New Member

    Hi Alex. Zinsser gardz will toughen and seal any parts of plasterboard where the top paper has ripped away whether or not it exposes the gypsum underneath allowing filler to stick properly. Once the filler has dried, sand smooth and if needed refill and sand whole wall smooth and apply a full coat of gardz. It's a recommended primer for bare plasterboard.

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