Installing Drywall: Mudding and Taping
By Mark Donovan
Installing Drywall, or hanging drywall as the professionals usually refer to the task, can be done by the homeowner. However, it is usually best done with two or more people as it requires significant lifting of heavy material. Mudding and Taping can also be performed by the homeowner, however these tasks require some practice and artistry.
Measuring and Ordering Drywall
Prior to actually hanging the drywall, the material first needs to be ordered and delivered. To determine how much material to order, measure all of the surface area, starting with the ceilings and then the walls. Calculate the total square feet and divide by 32. The result should give you the number of 4’x 8’ sheets of drywall required for the job. I would also recommend adding another 5-10% to this figure to account for inefficiencies. Drywall does come in larger sheets, such as 4’x12’, however for a Do-it-Yourself homeowner these larger sheets can become unwieldy and maybe even impossible to bring into the existing home.
For bathrooms or other moist areas Greenboard should probably be used as this material is moisture resistance.
For bathroom areas where ceramic tile is to be applied, e.g. Shower/Bathtub areas, Concrete board should be used. The concrete board is also referred to as Wonderboard or Durock.
Joint Compound and Fiberglass tape will also be required for Taping and Mudding. Joint Compound typically comes ready-mixed in 5 gallon containers. I would suggest 1-2 containers per 500 square feet of drywall. Fiberglass tape is quite inexpensive so I would suggest picking up 2 to 3 roles for most Do-it-Yourself drywall projects.
Drywall screws or ringed nails will also be required. Typically I use 1.25” length screws or nails. Also, strips of corner bead will be required.
Drywall Tools
Prior to starting drywall installation, you need to obtain the proper tools. A Drywall Lift really comes in handy when hanging sheetrock/drywall on the ceilings. You can rent Drywall Lifts at hardware or home improvement stores. If your budget does not allow for this cost, Jacks (or Ts) can be made out of 2”x 4”s. The Jacks (or Ts) should be of a length such that they are just an inch or two taller than the height of the ceiling and have a cross beam that is approximately 3’ in width. Usually there are a couple of 45o angle braces connecting the crossbar to the main stem of the Jack. The Jack can then be used to hold up the drywall to the ceiling while it is screwed/nailed into place.
In addition to the Lift or Jacks, a drywall screw gun, hammer, T-square, carpenters knife, drywall saw and a keyhole saw are required. The keyhole saw is used for cutting around electrical boxes.
If mudding and taping are to be performed then Taping knifes, a Corner knife, sand paper, a pole sander and a Mud easel or pan will be necessary. For the taping knifes you will need a 6” wide blade and a 12” wide blade.
Preparing the site for Drywall
Prior to hanging the drywall, make sure the building inspector has first approved the Framing, Plumbing, Electrical and Insulation jobs. Secondly, a vapor barrier should be applied over the insulation on the outside walls if un-faced insulation was installed. Frequently sheets of plastic are used for creating the vapor barrier. The plastic is simply stapled to the framing, covering the insulation.
Finally, inspect all of the framing carefully. Ensure that nailers (e.g. 2” x 4”s) are existent at each corner and header, that the framing is straight, and that the framed walls create smooth planes. In addition, the ceiling should have strapping applied (1” x 3” cross boards). Also, make sure metal protection plates have been installed to studding where sheetrock screws or nails could inadvertently penetrate plumbing pipes or electrical wire.
Safety
Drywall installation is dirty, heavy work. The Gypsum in drywall can be irritating to the eyes, lungs and sinuses so wear safety goggles and masks to avoid breathing in the material. Gloves are also recommended to protect against sharp blades.
Installing Drywall
Start with the ceiling as this will allow the sheets on the walls to help hold the sheets on the ceiling. Use the Drywall lift or Jacks to hold the sheets in place while screwing or nailing them to the ceiling. The screws or nails should be installed such that they are slightly recessed and create a small dimple without breaking the paper. Screws or nails should be applied every 8 to 12 inches on each stud. Screws are typically stronger and can be placed further apart, e.g. 12 inches. It is best to fasten the screws/nails to the edges of the drywall first and then fill in the field afterwards.
Rows of drywall should be applied in a staggered pattern. This will create an interlocked pattern that creates a tighter and stronger ceiling/wall.
After the ceiling has been completed it its time to move on to the walls. Drywall should be applied from the top down, with the sheets hung perpendicular to the floor joists or studs. Again the rows should be staggered. The bottom piece should sit about ½ inches from the sub-floor.
For purposes of efficiency and strength it is best to apply the large sheets of drywall over the doors and window openings and cut out the excess later. This will create stronger/cleaner looking walls and save significant time.
Installing Corner bead
Once the drywall has been installed, corner bead should be applied to all outside edges. Corner bead should be nailed every 6-8 inches and penetrate the framing.
Taping and Mudding
Again start with the ceiling. Apply a skim coat of joint compound over the surface of a seam using a 6” wide taping knife. If the seam is wide, apply a liberal amount of joint compound to fill it. While the Joint compound is still wet, apply the fiberglass tape over the skim coat of Joint Compound. Make sure the seam is centered under the tape. Once the tape has been installed, apply additional Joint Compound over the tape, again using the 6” wide taping knife. Continue this for all of the seams. Note: the tape will still be visible. Additional coats will eventually hide it.
The inside corners are usually the most tricky and require practice. Patience is the best advice and note that additional coats will be applied later to smooth out any imperfections.
Once the seams are done, using the 6” wide taping knife, apply mud to all of the screw/nail dimples. A skim coat is all that is initially required.
Note: When applying the mud over the tape and screw/nail dimples, make sure all excess material and uneven patches are smoothed down with the blade. This will reduce sanding later.
Once the ceiling is done, you can move on to the walls. Repeat the same process, however with the outside corners just apply a liberal coat of joint compound to the valley that is formed by the corner bead. This valley typically represents the first 3 or 4 inches from the edge of the corner.
Once the first coat has been applied let it sit overnight or until it is dry, prior to starting the second application of Joint compound. Make sure to completely clean off the taping knife, the mud easel and any other containers or instruments that have mud on them prior to finishing up for the day.
Applying the Second Coat of Mud
After the first coat has thoroughly dried, it is now time to apply the second coat of mud. It is this coat that should hide the tape.
Again, start with the ceiling. Using the wider taping knife apply a generous amount of joint compound over the taped seams as you want to build up the area over the tape. Taking large strokes smooth the joint compound over the tape applying more pressure to the side of the taping knife further away from the tape. This will help to leave more mud over the tape. When complete, the mud should cover an area that extends beyond the width of the tape by 2 to 3 inches.
After the seams have all been completed, apply a second coat of mud over the screw/nail dimples. With this second coat, flare out the mud over the dimples such that the diameter of the mudded area is about 3-4 inches in diameter.
For the inside corners a Corner knife may come in handy. Corners involve a little artistry so again take your time. Apply a generous amount of joint compound and then run the Corner knife down the corner starting from the top. Take long, even strokes. A 6” taping knife may also be helpful to smooth out any imperfections.
For the outside corners, using the broad taping knife apply a generous amount of joint compound and flare out the material such that it extends out 6 inches or so from the corner. Again, apply more pressure to the blade side that is further away from the corner so that you leave more mud nearer the outside corner.
Once the second coat has been applied let it sit overnight or until it is dry, prior to starting the final application of Joint compound. Make sure to completely clean off the taping knife, the mud easel and any other containers or instruments that have mud on them prior to finishing up for the day.
Applying the Final Coat of Mud
After the first coat has thoroughly dried, it is now time to apply the final coat of mud. It is this coat that requires the most artistry and the least amount of joint compound. Here you are simply applying a final skim coat to the already mudded areas.
Prior to applying the skim coat it is best to take your wide taping blade and lightly pass over the mudded surfaces. This will remove any bumps or ridges.
Again start with the ceiling seams and apply a small amount of joint compound using the broad taping knife. Again continue to flare out the seam by extending the mudded area such that about 6 inches resides on each side of the now invisible tape. Remember this is a skim coat so little mud is required. The purpose of this coat is to effectively fill in any lines or recessed areas.
After the seams have all been completed, apply a final coat of mud over the screw/nail dimples. With this second coat, flare out the mud over the dimples such that the diameter of the mudded area is about 6-8 inches in diameter.
For the corners use the broad taping knife and add just enough mud such that you can flare out the mudded surface area to about 8-12 inches, taking care to filling in any lines or dimples.
Once the final coat has been applied let it rest overnight or until it is dry,
Sanding
Sanding is a very dusty and dirty mess so please uses goggles and a mask.
I find it best to use a pole sander with an open screened sand paper material specifically designed for sanding sheetrock/drywall mud.
Lightly sand all of the taped areas, however concentrate sanding on the outer edges of the mudded areas such that all seams and ridges are eliminated and blend into the main surface areas.
Once sanding is complete, vacuum up the dust and you are ready for priming and painting the walls and texturing the ceilings.
Me_Donovan@comcast.net
http://www.homeadditionplus.com
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Over the past 20+ years Mr. Donovan has been involved with building homes and additions to homes. His projects have included: building a vacation home, building additions and garages on to existing homes, and finishing unfinished homes. Mr. Donovan's formal education and profession have been as an Electrical Engineer and Marketing Manager.
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