You Can Skim Coat Rough Plaster Or Drywall ...Prep For Wallpaper Or New Texture

Over the years I have been in business, I have had a lot of dealings with paper hangers. Skim coat prep is NOT their thing.

I really admire them as professionals, since many of them are excellent craftsmen. (Shoot, I can barely manage to wrap a Christmas present).

With few exceptions, the one thing they hate is having to hang wallpaper over rough or textured walls. They can hang a filler layer first, if they choose, to mute the coarseness of the surface, but this option is often not their first choice.

There is a better way to prepare the wall or ceiling for paper, but they would prefer this to be done for them ahead of time. This means skim coating the old roughness with new material to render it smooth, perfect for wallpaper.

So the call comes to me. I guess I have applied skim coat to many, many thousands of square feet of old plaster and drywall for paperhangers. It's not difficult really, but it is a job most of them would just rather offload and get on with what they prefer - hanging paper.

Here are some basic tips for how I approach it.

(For my full step by step, professional system, see my digital download manual.)

First, be sure the surface is reasonably clean. Usually I will ask the customer before I arrive to wipe down the walls with warm water and a sponge.

Second, if the walls have cracks, I clean them out, fill those that need it and then stick tape over all cracks with joint compound. In other words, treat each crack like I would a drywall seam. If this step is skipped, there is a very good chance that at least some of the cracks will reopen and show through your new wallpaper later.

Hot Mud?

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SIDEBAR: You don't have to use hot mud for taping or skim coat. I do to make things go faster. You can use regular all-purpose joint mud.

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Third, because I want to minimize my number of trips to the job, I will use hot mud to smooth out the walls. If I have any doubts about getting good adhesion, I will stir some plaster bonder into my water before mixing in the powder.

Fourth, I use all-purpose joint compound for the final smooth coat of mud. This is finer grained than the hot mud I use and is a lot easier to sand.

If all goes well, I can do my three coat system in one day. I then return a second day and sand out the tool marks, lines etc. before putting on two coats of drywall primer/sealer. (PVA primer)

Now the paperhanger will be happy!

Tips for the Applicator (you?)

My system involves using a plasterer's hawk and trowel. This is a wonderful pair of tools, but takes some practice to get the hang of. You might find it easier to use a ten-inch drywall knife and large mud pan.

First, carefully apply masking tape to all trim. The blue painters' tape is less likely to pull paint or leave residue behind on the trim. Make your masking tape lines as straight as possible. Stay on the trim. You don't want any overlap onto the wall.

Second, lay on the mud (you should probably use all-purpose joint compound) for the first layer of skim coat going in the direction most comfortable to you.. Try not to get the mud on too thick. Don't worry if it doesn't look too hot. After all, this is only your first coat.

It also helps to start at the top of the wall.

Third, for your next layer, you will do try to do the opposite of the first layer.

You will be smoothing things out so it looks better this go-round.

With both of the first two layers of skim coat, you will likely get raised lines forming along the edges of your strokes. These are unavoidable, tho you will get better at minimizing them as your skill improves. Just let the present layer dry, then go back and scrape or sand off those lines before you start your next layer.

The rougher the texture or defects you are covering, the more layers will be needed to get your final surface. When you first start the skim coat process, you can often knock off the worst of the high points with a stiff putty knife held at a flat angle to the surface.

If your rough wall is one you have already done repairs on in advance, your job now is to fill in the untouched areas, so that the whole wall is smooth.

To get the full skim coat instructions to do an excellent job, check out the ebook here.

And, finally, don't forget to put on a couple of good coats of drywall primer/sealer (water-based PVA). This eliminates surface porosity and make the paperhanger's task much easier.

If at this point, you decide you would rather put on a new texture instead of wallpaper, here is a resource you may want to utilize. Wall Texturing Techniques

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If it's drywall you want to get perfectly smooth, then you need to learn how to skim coat drywall.

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