Do you have to Skim Coat the entire piece of drywall before painting it? Someone told me you just have to prime it and not skim coat the entire piece. Is that true?
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Replies
Skim coating is the Cadillac finish -- super smooth (if done right), but a lot more work/expense than standard mudding. Most drywall you see is not skim coated.
Priming after skim coat
How long does the skim coat have 'cure' before it can be primed?
richardi
skim coat-dry it out-prime it.
skim coat-dry it out-prime it
Ok, I know the steps. How long is the normal 'dry it out' period? In an unheated house?
I'm trying to schedule the painter...
It depends on how thick the mud is, what the temp is, what the humidity is, etc. For the small amout of stuff I've done, in a heated house in winter, I'd guess you're good to go in 24 hours. Could be 3-4 days in the right wrong conditions.
The mud changes color as it dries, and you want it to be white for most of a day, at least. (And remember you'll generally want to skim, then come back 24 hours later and touch up, then let that set 24 hours.)
The painter may have some opinions on the matter too.
well scuse me.
All bets are off in an unheated setting.
If you skimmed prior to the joint treatment dried, this will lengthen the time for full dry in those areas.
Bucket mud could likewise alter normal dry time.
Get the painter over there and have him look (if he's more than just one that puts paint on the wall).
Heat introduced would be a safe bet-but not a propane job heater or salamander-they put out too much moisture into the air.
Weren't you the one with in floor heat? Turn on the boiler-run the floor-that'll dry it out best.
Skim Coat Drying Time
Well, turning on the heat would be ideal. If it was installed. This is new construction and I'm trying to get an understanding of the order of each 'task'for scheduling purposes. The skim coating is being done now, to be followed by the primer painting. Then the radiant floor, finished floor, trim, etc.
richardi
There are certain orders in construction, but then there are situational orders.
Most heating systems are kept off during drywall install to keep dust out of the system. A boiler/radiant infloor heat can in most cases be operated while construction goes on-this provides work comfort as well as the proper drying scenario for compound, paint, wood finishes (stain/finish), and the concrete itself.
Otherwise you take a bit of a chance. However, I've rushed coats of drywall b/4 and not seen any problems (except for tape lift on occasion (whether or not rushing recoats had anything to do with it).
Ask the guy skimming how long.
Pass that onto the painter.
Those of us in the trades should be able to "see" it and give you the advice you need. Drywall finishing times are site specific.
Certain orders
Calvin -
I can certainly appreciate that there are (logical) steps, that tasks are dependent on the completion of other tasks.
It seems that my GC is allowing the heating contractor dictate the timing of the order. Additionally, said contractor has stated that he will take up to 5 weeks to install the radiant floor heat (1800 sq ft). So they are using propane heaters to heat the house in the meantime. It is my undertanding that propane heater add moisture to the air that willl increase the drying time.
So when the primer can be effectively applied remains a mystery!
I just want to tell the GC to screw and I'll finish this project myself...
Yes before painting use skim coat on drywall. Skim coat is the fine coat to smooth the surface. Skim coat must be thin. After finishing skim coat , walls look so beautiful.
Yes before painting use skim coat on drywall. Skim coat is the fine coat to smooth the surface. Skim coat must be thin. After finishing skim coat , walls look so beautiful.
do most people just prime the dry wall and then paint without the skim coat?
Most people hire someone else to do the drywall finishing.
And as to whether "most" of the people hired do one or the other, that depends on the crowd you run with. I'd be very surprised to see much skim-coating in a standard tract home or even in a mid-scale McMansion. But when you get into homes where a lot of attention is paid to fit and finish then skim-coating is more likely.
You asked: "Do most people
You asked: "Do most people just prime the dry wall and then paint without the skim coat?"
Yes. The vast majority do it that way. I've never heard of skim coating an entire wall until I read this thread.
Well, I am hoping the finish matches the Plasterboard finish of the existing walls, but I am thinking to get that smooth I might need to skim coat it.
"Plasterboard", at least as
"Plasterboard", at least as the term is commonly used in much of the country, is another name for "drywall". As is "Sheetrock" -- a trademark name -- and "gypsum board" or "gypboard". (Though "gypboard" might also be used to refer to gypsum sheathing.)
The earlier product would be "rock lath" or a few other names -- a base for 1 or 2 layers of conventional plaster. There is also a product sometimes called "blueboard" which is designed to be skim coated.
The smoothness of the finish of any plaster-like wall surface is highly dependent on the skill of the finisher and the time taken. When seeking a super-fine finish a sheet of drywall may end up being 30% covered with mud. Or more, if there are irregularities that need to be handled.
Skimming isn't really hard, just takes more time. Thin your compound so that you can roll a thin layer on the wall with a paint roller. If you're working by yourself don't do over 3 or 4 feet at a time or it will start to dry and be hard to smooth. After you've rolled an area you can scrape it with a large drywall knife or buy a Magic Trowel which makes it real easy. Scrape off as much mud as you can, let the room dry then hit it with 200 grit sandpaper. Prime with PVA and then paint. It will look great.
Sponge sanding
After you skim coat and sand (if needed), clean up the surface.
Then take a grout sponge, wet it, and wring it out so it's pretty dry. "Wash" the wall with the barely damp sponge. The little bit of moisture in the sponge will really smooth things out nicely. It gets joint compound about as close to glass-smooth as possible.
I don't know if there is an official name for it, but I've always called it "sponge sanding."
It's especially effective when you are NOT skim coating an entire wall. On walls that are spot-mudded (just seams and screw heads), sponge sanding the joint compound gives a very smooth transition from joint compound to bare drywall paper. You don't want to scrub the bare paper too much or too hard with the damp sponge though, as you can cause the paper to pill.
As an alternative, you could consider just spot-mudding the wall (mud the seams and fastenr heads). Then roll on a heavy body primer, some even roll on thined out joint compound, then trowel it smooth.
Skim coats
There is no doubt, that a skim coat looks better and is easier to decorate and to live with.
Wet plastered walls and ceilings are also air tight.
Have the room plastered before you fit electrical sockets and wood work.
I am old enough to remember when all drywall was skim coated but the giuys in the business used to do plaster so they knew all about using a hawk and a trowel. Sanding was minimal. Sometime around the mid 70s the slap it up and paint it method started to being the norm.
I had to argue with the rockers to get them to skim coat the drywall when we redid the bedroom.
These days, they usually shoot "texture" on the wall with a gun.
it must be rock lath then. It is 3/4 of an inch thick with drywall behind it and plaster on top of that.
No it is just a thin coat of mud over the drywall.
There are also a lot of older homes in Florida with a half inch or so of stucco over wire mesh, finished smooth.
In my new addition I did smooth stucco right over the block wall.
There were a number of different schemes prior to drywall becoming the norm. First there was wood lath, of course, with 3-coat (or sometimes 4-coat) plaster on top -- scratch, brown, and finish layers. Next came various types of metal lath, but that was rare, except in wet areas. Then rock lath -- generally 48"x16" pieces of brown-colored gypsum board, still with 3-layer plaster. Then several variation of larger boards, usually with only one or two layers of plaster. But drywall/plasterboard, finished without skim coating, has been the norm since some time in the 60s.
As I'm remembering, the scratch coat of a 3-layer system would be about 3/8" thick at the thinnest. It's pretty much like brick mortar and it's "scratched" with Paul Bunyon's comb when partly set to provide "tooth" for the next layer. The brown coat is more of a plaster but has sand in it, making it brown. Maybe 1/4" thick -- thicker or thinner as needed to produce a flat surface --this layer is made as flat as the final wall. The finish coat is white plaster, similar in consistency to drywall mud. Only a thin layer -- about 1/8" -- is used.
So that adds together to about 3/4", which may be a bit thick but in the right neighborhood.
What I've found works better (with my unsteady hands) is to use a notched trowel to apply the mud, then knock it down with a smooth trowel. That gives you a more even job to start with.
Minor point: There are several types of stuff that are legitimately called "plaster", some of which are "setting type" and some not.
Geof
You can skim coat all the drywall products you mentioned above.
In addition, you can skim a whole lot of other things as well.
The only thing limiting you are the products used and the application.
to say that you can't above is not true.
"Someone" can tell you
"Someone" can tell you anything. I've lost count of the times I've seen folks ignore professional advice because "someone" told them of a shortcut.
First off, what is the final finish you want? If you want a heavy texture, you don't need a skim coat. If you want a perfectly smooth and uniform look, a skim coat might be a requirement. Visit the USG site and read some of their stuff about different drywall finishes.
Not all primers are the same. If the 'primer' you're looking at is the $10/gallon slightly colored water from the home center, you'll still need the skim coat. If, instead, you use a $40/gal "heavy body" primer marketed specifically for new drywall, you can probably skip the skim coat.
Sounds like most folks here like to 'skim coat' the hard way.
Unless a texture is being applied, I've found it necessary to skim coat almost everything. The paper face of the board will always have a different sheen from the sanded joints, unless you skim coat.
The best way is to "paint" the wall with a factory-prepared "high bodied" primer, like the one US Gypsum sells. If that's not handy, or you have a small area to prime, you can make a decent substitute by thinning pre-mixed mud 50/50 with water, then 'painting' that on with a roller. Back-rolling then gives a very nice satin finish.