I removed an ugly chunk of trim from my wall (I believe it's called a chair rail) because I kept bumping into it and bruising myself. I thought I could patch the wall myself, but the plastering job didn't turn out well. It's very noticeable under ambient or raking light, though it looks fine under normal lighting. How should I fix it? Does it just need more sanding, or should I run a new strip of plasterboard across the wall (something like 200mm × 3000mm)? Or is there a better approach? I have a 3 year old, so the dust is a challenge. I was thinking the approach would be more sanding using a sander that has a vacuum, re-patch using a light coat of Gyprock and then paint the wall? Any advice?
Welcome to the Bunnings Workshop community, it is wonderful to have you with us @BibinNahas.
The problem you are having is that you've gone much too narrow with your plaster application. Most beginner plasterers, including myself when I first did it, think that using less plaster makes it less noticeable. The reality is it is extremely difficult to hide variations in height over a narrow patch. The wider the patch is, the easier it is to feather the plaster out so the change in height is not noticeable.
With this in mind, I’d start by sanding the area back, so it is as flush with the surrounding wall as possible. A plaster sander such as this https://www.bunnings.com.au/builders-edge-220-x-80mm-diy-plaster-hand-sander_p0730315 or this https://www.bunnings.com.au/hyde-225mm-radial-sander-plaster-tool_p0420950 would be handy for this step.
From there, apply a much wider patch using topping compound and a wide taping knife like this https://www.bunnings.com.au/kango-355mm-stainless-taping-knife_p0098426 . I'd aim for the patch to be around 400mm tall along the full width of the patch. Ensure you use topping compound, as it is a much smoother, fluffier material to work with, which is much easier to sand.
Plastering is all about applying material then removing it, so don't be shy when you apply it. Put a thick coat on to build up the centre of the patch, then use your taping knife to remove it, feathering the edge away from the centre.
Once it’s dry, give it a sand, check the surface from a few angles, and repeat with another thin coat if needed before priming and painting.
Allow me to tag some experienced members to see if they have any advice they can offer - @courtneyandconstruct, @OurPretty_LittleHome, @Nailbag.
Let me know if you have any further questions.
Jacob
I agree with Jacob's advice. One thing I'd add is to make sure there isn't any loose or peeling paint around the repair before you start again. Give the edges a light scratch with a scraper or filling knife—if any paint lifts, peel it back until you reach a solid edge, then feather those edges smooth. Otherwise, you'll end up patching over loose paint and it'll still show later. After that, use a wide skim of topping compound, sand with a light held across the wall to check for high and low spots, then prime before painting. It takes a couple of thin coats sometimes, but you'll get a much flatter finish than trying to hide it with one thick patch.
Thank you Jacob and OurPretty_LittleHome. I realise my mistakes now. The biggest one apart from miscalculating the effort was trying to apply the patch in a narrow area. As the wall is in a key area of my house, I want to fix it properly but the dusts are a challenge as we are also living here with my daughter. If its alright, I have a few more questions. I sincerely appreciate your time. 1. Do you think it will be easier and faster to hire a sander with vacuum to sand it back down flat? I have a Ryobi Palm sander - https://www.bunnings.com.au/ryobi-100w-palm-sander-with-bag-rps100-s_p6210776?srsltid=AfmBOopQ6152bsokKAJ-5b-LCCew27TJ1V6UOQkQdNFUq1OnIrkOXOnZIdo but it is sending dust out and not really collecting them. 2. Is Topping compound the only one required for all coats? I thought I needed the https://www.bunnings.com.au/gyprock-csr-2-25kg-less-mess-multi-purpose-joint-compound_p0173344?store=6249&gclsrc=aw.ds&gad_source=1&gad_campaignid=21122993677&gbraid=0AAAAADtbEB_bbSG1YEBjhTCe-M2e9d2cG&gclid=CjwKCAjwyuDTBhB-EiwANCQhLLmV68qUBdIB6x-2VPNrv8yqzHFB9aTkzvHc_A9NbJdUpHkjhYWC7hoCCqkQAvD_BwE 3. Is there a tool that will make sure the Topping compound is being applied as flat as possible? (maybe thats the Taping knife) 4. When you said "feather those edges smooth", do you mean sanding it with a fine grit paper (like a very high number)? 5. By "wide skim of topping compound", did you mean using the taping knife to apply the coat? I am having difficulty getting the plaster on to the knife, So I had been putting a scoop on the wall using a small taping knife and then trying to even it out. Should I rather put the scoop on to the knife and then apply to the way? 6. For sanding this down flat to restart my work, should i just use a very coarse sand paper like 60 or 80?
Hi @BibinNahas,
Unfortunately, we do not hire them out, but if you were to get a tool to speed up the sanding that can be attached to a vacuum cleaner, this style of sander is what you'd want to look at https://www.bunnings.com.au/full-boar-750w-225mm-drywall-sander-kit_p0335362?store=7086&gclsrc=aw.ds&gad_source=1&gad_campaignid=21118986128&gclid=EAIaIQobChMIv9q4_-2UlgMVNKhmAh0-ShPPEAQYASABEgLbi_D_BwE . Alternatively, one of these https://www.bunnings.com.au/ozito-1220w-225mm-portable-drywall-sander-dws-225_p0680648 is relatively cheap and has a vacuum connection port.
If dust is a concern, it might be worth setting up dust containment around the area. There are systems such as the https://www.bunnings.com.au/dta-australia-dust-shield-temporary-wall-system-kit_p0730661 that can be used, but you can also just use some https://www.bunnings.com.au/builders-edge-3-7m-x-7-62m-x-0-07mm-plastic-sheet_p0427685 and tape it to the floor and ceiling, adding a zip door if you'd like.
Topping compound is specifically designed for the topcoats so it is smooth and easy to sand. It is not designed for strength. Usually, you would use a base coat first, followed by a coat or two of topping compound. All purpose compound is somewhere in between base coat and topping compound in terms of strength and workability. You could certainly use all purpose compound in this situation, but it is a little bit harder to sand and get perfectly smooth than a topping compound is. Check out How to choose the right plaster for your repair for a bit of guidance on different plaster products.
The taping knife is what you would use to get things as flat and smooth as possible.
When I say feather the edges, you want to build up the compound in the middle and angle the taping knife slightly in towards the plasterboard on the top and bottom of your patch. Essentially, you are trying to build a very small mound over the patch that tapers down into the plasterboard. Angling your knife slightly is how you apply that feathered edge. Do one pass over the top edge, then another pass over the bottom edge, maintaining that slight angle.
You don't need to apply the plaster with your wide taping knife, but you need to use it to strike off and remove the plaster, maintaining that slight angle. Personally, I struggle applying a large amount of plaster with a knife that large, as do most people who aren't professional plasterers. You can apply the plaster with a smaller applicator such as a https://www.bunnings.com.au/hyde-6-plasterboard-joint-knife_p0730103 , then strike off with the taping knife. It would also be worth grabbing a hawk to put the excess you've struck off on.
For sanding it back, yes a coarse grit sandpaper such as 80 would work well. Just be careful not to go too deep.
I hope this answers all your questions. I know it is a lot of information, so please don't hesitate to ask if you need some clarification about anything.
Thank you JacobZ. I got almost everything here and yes, its too much info for me at this point. I think I would benefit from isolating the area using builders plastic and then finishing the work by hiring a sander and vacuum. I assume this would mean the least amount of dust is in room. Do you know how I can stcik builders plastic on to the walls and ceiling?
You could use Builder's plastic or plastic drop sheets, which are typically a lighter grade of plastic. I'd go with the plastic dropsheets as they can be attached with Painter's tape. Mitchell
Hi @BibinNahas
I think it is worth mentioning that your wall appears to have a slightly textured finish and that will also make the repair harder to hide, maybe one of the experts here can suggest a roller to try and match the finish.
Hi @R4addZ,
It looks like a classic stipple finish that has built up over the years from multiple layers of paint applied with a 12mm nap roller. Once the undercoat and a couple of coats of topcoat have been applied, the repaired area should start to match the surrounding texture reasonably well.
If the repaired area still looks a little too smooth, @BibinNahas could try using a 15mm nap roller for the topcoats. This will help build up the texture a little quicker and make the repair blend in better with the existing wall.
Mitchell
@R4addZ I used a 12mm nap 270mm roller on the entire wall before the pictures. The texture isn't happening anymore due to the bad plastering I reckon. @MitchellMc, what if I knock the ridges and lumps down first with a broad taping knife or a scraper held flat and then sand using a 120 grit paper? Will that get me to a flatter starting position for re-plastering properly this time?
@MitchellMc
BillfromBuderim is going to be really confused! 😊
A quick scrape and a sand would help reduce the prevalence of the texture, but I wouldn't say it is essential. Your plaster will stick to it fine regardless of the texture. I'd just focus on getting the plastering sorted, then you can worry about the texture later.
Like @MitchellMc mentioned, that kind of texture happens when paint is applied with a thick napped roller. You want to get your plaster nice and smooth, then you can apply your paint with one of these rollers to build up the texture. After a couple of coats, it should blend in nicely.
The question about quick scrape and sand was to know if that would save some sanding effort to cut through first and sand later. I get your point.
Thanks guys. I appreciate it
Bibin
Just recommendation to consider if to use a powered sander or hand sanding would be to go hand sanding. From experience the Full Boar tool is difficult to use and if not used correctly can cause wall damage very quickly. And also like the smaller Ozito model they are specialised tools that you have to consider if your will use again. So you could consider this Hyde hand sander with dust extraction. Just remember any for of dust extraction when it comes to plaster dust must be connected to a workshop vacuum and not a domestic vacuum. Plaster dust can destroy a domestic vacuum's motor very quickly. This type of sander is can be used with or without dust extraction and you can buy similar hand sanders without. This is the type of sander I would recommend using with a medium-fine sanding mesh. They are very efficient and would make the job of sanding back those high points manage those high points very easy to manage. I would be using the hand sander over scraping off the excess with a scraper as it will be easier to control. It might just mean going light handed starting off with a courser mesh.
A tip for keeping dust down is to close doors and windows in the room and turn off any heating ducts. That way most of the dust should fall straight down. For applying and sanding off top coats, this DIY video is worth a watch. Just skip through the bits that don't apply.
Nailbag
Thank you Nailbag. I appreciate it.
Just another quick question. Would it be less messier to cut the plaster out at about 200mm width all along the room and to put a new one and to lightly patch this new one? Or is the extensive sanding back flat and re-patching from current state still better?
No, I don't think that would be less messy, @BibinNahas. Cutting out a 200mm strip and installing new plasterboard would leave you with two joins that need to be taped and feathered out, which would still require sanding.
I'd stick with sanding the existing repair back and re-patching it as discussed.
Thank you MitchellMc . I appreciate your time and advice.
