HOW TO SKIM COAT DRYWALL



A skim coat drywall process is used by most drywalling and plastering professionals to level out and remove any roughness that your wall or ceiling surfaces may have.

Skim coating drywall (sheetrock) involves drywall compound (mud or plaster), an 8" taping knife (drywalling trowel) and mud pan (or hawk).

With the help of said tools and materials you can apply thin layers of compound onto the surfaces that your wanting level.

skim coat drywall or plaster


After a few coats of mud followed by sanding, priming and painting you can greatly enhance the look and feel of your uneven walls and ceilings.

Below you will find how to instructions for smoothing out all of those bumps, humps and grooves that your surfaces may have.

SKIM COAT DRYWALL COMPOUND



Type of drywall (or plaster) compound used depends entirely on the job being done. Surface areas that have a number of demarcations, waves or grooves may require the use of a harder, slower drying powdered setting compound.

Smaller sized surfaces on the other-hand might be better suited to a pre-mixed all purpose product.

Keep in mind too, that powdered muds can dry very hard and are somewhat more difficult to sand than a softer premixed compound.

With that said, applying a premixed mud onto a larger sized job might result in the compound setting up to slowly. Especially when one needs to apply more than a single coat of mud in a 24 hour period.

For most large projects apply a faster drying product as your first coat (e.g. Durabond 45 or 90) then follow up by laying on ready mix or pre-made all purpose compound.

Those who have less experience with drywall mudding (or plastering) might find that all purpose ready mix compound is their best bet.

Talk to local drywall suppliers regarding your specific project, along with tools or materials needed prior to beginning the skim coat drywall process.


PREPARATION TO SKIM COAT DRYWALL



Remove all furniture etc., from the room that your going to be working in. You can now plastic, mask or cover the floors, wood trim and other items that your not wanting to wash mud off of.

Light switches or plug plates, along with lighting fixtures (if your doing the ceilings) need removing. All exposed electrical boxes are to be taped or masked off.

Furthermore, the surface receiving compound should be clean, dry, non-shiny and without stains. If stains are visible a stain blocking primer is recommended.

Prior to, or after skim coating, be sure to apply the proper sealer or primer in relation to what the primers job will be (e.g. seal, bond or block stains).


SKIM COAT DRYWALL TOOLS & MATERIALS



To skim coat drywall, processionals like to use a drywall hawk and trowel or mud pan and broad taping knife.

Instructions that follow are for the mud pan and a 6" to 8" taping knife. As the pan and drywall knife are the easiest skim coating tools for a beginner to use.

To skim coat drywall you may need a number of tools, products and materials. Use the list that follows to choose items that will work best for your specific job.

  • Painters plastic
  • Painters tape
  • Drop cloths
  • Roller, roller cover, paint tray
  • Paint roller extension pole
  • All purpose drywall mud or other texture compound
  • Mud pan, drywall taping knifes or trowel
  • Soap/water (if needed)
  • Very clean (or new) 5 gallon buckets or pails
  • Heavy duty electric drill with mud mixer (paddle)
  • Old close (or coveralls), hat, gloves, & goggles
  • Ladders, platforms and sawhorses (as needed)
  • Sanding sponges (fine & medium)
  • Swivel sanding head
  • Sand paper (block for paper)
  • Sand paper (120 to 220 grit)
  • Electric palm sander (if needed)


Amazon.com carries an assortment of different tools and materials for skim coating your walls and ceilings. By using Amazons five star rating system along with their no or low cost shipping you should be able to find a good selection of products for the job at hand.


MIXING SKIM COAT DRYWALL COMPOUND



Before you begin to skim coat drywall you will need to mix the compound. To do so, place your compound along with the recommended amount of water into your mudding pan.

It's usually 2 parts powdered compound to 1 part clean room temp water. Read the label on your compound container to be sure.

Pre-mixed mud also requires extra mixing, add much less water when doing so though.

Mix your water and mud in the mud pan with a small drywall knife. Your mixing knife should be just a little smaller in width than the width of the pan.

Keep mixing water (very small amounts) and mud (as needed), until the compound is a nice creamy cake batter consistency. You want your mud smooth and having no lumps while at the same time able to easily stay on your knife when the knife is turned upside down.


ROLLER METHOD TO SKIM COAT DRYWALL



Another drywall skim coat method involves a paint tray, paint roller, thick piled roller cover and roller extension pole.

Using the mentioned tools you would roll your unsightly surface with thinned down drywall compound. Such a process is usually applied to surfaces that are quite damaged or poorly finished.

To complete the mud rolling technique, you want to start your project with about a gallon or so of mud.

The compound should be watered down and stirred to the consistency of a milk shake or very thick paint (with an electric drill and mud paddle).

Fill a paint tray with your thinned compound then roll the mud onto the surface in three foot (wide) by four foot (high) sections.

After rolling a section level it out with the help of your drywall trowel or wide (8" or more) taping knife.

Once a section has been completed move onto the next making sure to overlap each section with the other.

Keep rolling and troweling until your walls and ceilings are finished.

After the mud is dry, sand it out, then roll and trowel it again.

If on the other-hand your surface is reasonably level follow the instructions that proceed below.


USING A TAPING KNIFE TO SKIM COAT DRYWALL



Begin by using a ladder or platform (if needed) and a pan of mud along with an 8" to 12" broad knife. What you want to do is move some mud to the edge of your pan and onto the knife. I like to try and keep an inch on either side of the knife clean of compound by wiping the corners of the mud filled knife onto the edge of the pan. You want to start with a good sized hot dog looking (length and width) dollop of mud at the edge of your knife.

While in the corner of a room (wall or ceiling), working quickly apply your compound to the surface. Keep drawing the knife (at a low angel) using even vertical lines pulling the mud along (this is called buttering).
Work your way from ceiling to floor (or wall to wall if your doing a ceiling) applying the mud then removing the excess by wiping at it with your un-mudded knife. After wiping excess form the surface place the extra mud from the knife back into your pan.

Continue buttering thin layers of mud (1/8th of an inch thick or so) while overlapping (and blending) each length (or line) with another length or line of compound.

Your making mud lines (side by side) filling your knife, mudding the surface then placing excess mud back into the pan. The whole process is like drawing thin strait grid lines vertically and horizontally (e.g., graph paper) with compound and a drywall knife.

Another alternative is to slather mud on then take the excess off using random back and forth motions in alternate directions. Sort of like icing a cake.

Proceed from one end of a wall (or ceiling) to the next wall, left to right, top to bottom, or floor to ceiling etc.

It's kind of haphazard (as oppose to grid like) but your objective is to work in manageable three foot by four foot sections overlapping swaths of mud and each section as you go along. While doing so you want to cover the entire surface with a thin layer of compound or plaster.

After your surface is finished let the mud dry, then scrape away (with a broad knife) any ridges and bumps that you might see (lightly sand, using a medium to fine grit sand paper, as needed).

You can now apply another coat of compound (if needed) haphazardly or if you prefer work in lines that are opposite from the first lines of mud that you applied (horizontal then vertical).


SKIM COAT DRYWALL SUMMARY



When using the broad knife (or trowel) it should be angled at about 25° or 30° to your wall or ceiling. You want to press reasonably hard while using your fingers to exert (lighter) pressure to the left, centre or right of the drywall knife. Doing so will give you more control of the mud along with less ridges.

No matter what technique you use the key is layering on thin coats of mud (1/8" or more in thickness), sanding the mud level, then applying more layers followed by sanding until your happy with your finished, flat level surface.

Groves and ridges are unsightly, keep in mind though that they will scrape off, sand out or can be carefully filled with more coats of compound.

With that said, a certain amount of extra sanding effort will be needed if ridges are caused by powdered compound or your skim coating is on the excessively rough side (an electric palm sander might be required).

Your first coat (which usually looks quite rough) should go on in a vertical fashion followed by two more horizontal (or vertical) applications (coats) along with touch-ups (if needed).

Once a surface has been primed you might have to follow up by re-mudding, sanding and spot priming. Reason being that primer tends to enhance all of a wall or ceilings imperfections once the primer has dried.

When using a powdered compound be sure to clean all of your tools immediately after use. Otherwise you may find the process of scraping dried on mud somewhat tedious. When cleaning tools never put mud down your drain or it could plug the drain solid along with slowing your flow of the water.

For the best results read and follow all label instructions including those on the tools, products and materials being used.

Talk to your local paint and drywall supplier regarding the skim coat drywall process, products, tools, primer and paint needed for your particular job.


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