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I've been trying to skim coat a room in my house using all-purpose mud (the green lid) that I have watered down. The tools I've tried to put the mud on are a roller then using a 12" taping knife or a Magic Trowel (basically a rubber squeegee) to smooth it out. I've put on three coats and these marks in the picture have been appearing. I have no idea what they are called so I haven't been able to find a solution to them. To me it looks like there is some dragging or pulling but I'm not sure.

Are these drag/pull marks?

How do I fix this since I am on a time limit? (Baby's coming in April and it's their room)

Marks on wall

John Martinez
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  • To liquid, so it is flowing down – Ruskes Feb 07 '23 at 18:23
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    If you are not starting from a bag of dry mix, you don't add water to drywall compound. If it's old, crusty and starting to dry on the pail, you either buy new and dispose, or relegate it to jobs that you are happy looking bad. Adding water won't save it. If you buy new, put a sheet of plastic on the surface before throughly re-sealing the bucket. And put it on with a knife. – Ecnerwal Feb 07 '23 at 19:12
  • i recommend watching a vancouver carpenter skim coat drywall video on youtube. Adding water and using a roller are viable application techniques. Did it look perfect when you applied it, you couldn't see these marks when it was still wet? – Fresh Codemonger Feb 07 '23 at 19:44
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    Um, what was underneath? Wallpaper? Poorly bonded paint? You’d learn a lot by scraping one of those sections back to the substrate. – Aloysius Defenestrate Feb 08 '23 at 02:37

2 Answers2

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These indeed look like application streaks.

Switch to a metal knife or trowel (they differ as to where the handle is), do not water down the mud (a splash is ok), thoroughly remix slowly so as not to fluff up to create air bubbles, apply proper 45deg angle or sharper (flatter to the wall), and press slightly harder.

P2000
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Are you trying to do this all in one pass?

Without the use of anything 'magic' you skim plaster no more than 2mm at a time with a broad square trowel known as a float, leave 20 mins to half an hour for it to start to go off, then re-skim with the trowel dipped in water or by gently spraying the surface, to polish up the finish. You can repeat this 'damp & polish' several times, each becoming smoother. Done well, this can actually achieve a slight shine to the finished surface.

A float, or finishing trowel

enter image description here

There may be some transpondian translation issues here - frankly I barely understood a lot of the terms you used. I would never dream of skimming with a roller, I had to look up what a 'taping knife' was & I have no idea how you'd use one for plastering - I cannot figure how you would hold one at a shallow enough angle to the wall with the handle sticking out the end like that. The 'magic trowel' looks just as inappropriate to the task, looks more like something you'd use for grouting.

Tetsujin
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