What is the difference between plaster and drywall compound

When you see a nice smooth wall, that is often the work of a plasterer using plaster. Filler is filler , it fills things. It is often used to fill gaps in things like walls and wood. Yonaida Aupperle Professional. Can you skim coat plaster with joint compound? The best way to restore the wall surface is by skim - coating it. Skim - coating is the technique of applying thin layers of gypsum-based joint compound over the entire surface.

Skim - coating can rescue a wall with numerous hairline cracks but cannot help a wall if the plaster is loose or unsound. Waldir Kenworthy Professional. What is patching plaster? Patching Plaster. He brushes a bonding agent over the lath and all plaster being recoated, then covers all but the smallest cracks with fiberglass mesh tape. Sharee Diabate Explainer. What is plaster of Paris made of? Plaster of paris , quick-setting gypsum plaster consisting of a fine white powder calcium sulfate hemihydrate , which hardens when moistened and allowed to dry.

Known since ancient times, plaster of paris is so called because of its preparation from the abundant gypsum found near Paris. Jeane Langemann Explainer. What is the difference between white cement and plaster of Paris? Made out of Gypsum, Plaster of Paris POP is a white powder that is used for giving early coats to the walls, giving shapes to structure or creating casts and likewise.

On the other hand, wall care putty is made out of white cement , like White Portland Cement. Makram Guille Explainer. What is skim coat? A skim coat is a thin coat of joint compound—also known as mud—that you can use to repair or smooth damaged walls. You may need a skim coat if you are repairing a crack, filling a joint, or leveling an area with an existing flat surface.

Nikita Mercade Pundit. What kind of joint compound should I use? Lightweight drywall joint compound is less dense than other types of drywall mud. This type of drywall compound is best used for repairing cracks and as a finish coat since it's easy to sand. Topping joint compound is ideal to use as a final coat.

Kristel Shakhovskoi Pundit. Why does Plaster of Paris get hot? Plaster of Paris is created when gypsum is heated to ? DMoore DMoore Searching the net I've found just a few mentions to plaster and drywall. One of them is talking about "plaster skimming", which is done on the whole wall from what I understand. The other mention that I've found says that joint compound is more britle, cracks easily and needs 3 coats to be applied, plaster is harder and hard to sand and can be applied at once.

If you are a master plasterer -which is a true art - then I could believe that plaster might take less time and it is surely more durable. I for one am not a master plasterer and if I did a house like this it would look like a kid did the mudding. Thanks, I will go for the right stuff then. The powdered variety is easier to come by here, it dries in 90 minutes.

The ready-mix in buckets takes a whole day to dry and isn't so easy to find. Daniel Griscom 6, 31 31 gold badges 28 28 silver badges 40 40 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. Featured on Meta. Now live: A fully responsive profile. Version labels for answers.

Here in the Midwest the most commonly used brands are Kal-Kote and Unikal. Kal-Kote is a two coat system which consist of an extremely hard cement like base coat which is applied to the blueboard and then is finished with either a smooth plaster or a texturing plaster.

Unikal is a one coat system which is applied directly to the blueboard after the joints have had a coat of Kal-Kote base coat put on them. Unikal can also be used for texturing as well as for smooth finishes. There are also different additives for plaster to speed up the setting action or slow it down.

There are fillers that can be added to make plaster less dense when it needs to be applied to metal lath, wood lath or if thick plaster is needed to feather out deep transitional areas or to fill big holes. Sands can also be used to get different texturing effects. Plaster, because of its properties and the fact that you cover the entire surface instead of simply making a raised mound over what you are trying to hide as with joint compound, allows the plasterer more leeway in utilizing trade secrets to create a more durable and uniform surface for paint.

There are many factors that impact how plaster reacts. Substrates, temperature, humidity, air flow, what is in the water and how long you mix it all must be taken into account by the plaster to decide if he should use additives and how much to mix up.

The amount of area you are trying to cover, how many corners you have to deal with and how thick you need to lay it on as well as is it a one coat or two coat system, is it a smooth finish or a texture and what type of texture as well as is it being applied to a bonded surface all dictate how thick you will want it.

It quickly becomes obvious why the untrained should not use plaster. There are different for plaster and joint compound are not interchangeable. There are many different styles of paper and fiberglass mesh tapes as well as a wide variety of beads and each of these products has a specific purpose. Joint compound does not have the tensile strength needed to prevent cracks from appearing.

Mesh tape is also thicker then paper tapes and will result in humps that are very difficult to prevent from being visible once the surface is painted. Fiberglass tapes can be purchased in widths ranging from two inches up to six feet. The narrower tapes are used for joints and the wider ones can be used to reinforce large cracks. When resurfacing old horse hair plaster or severely damaged walls the wider mesh tapes can be imbedded into the base coat plaster to help prevent future cracks or to stabilize the wall.

Beads : There are many different types of beads, stop beads, J beads and expansion joints are just a few. Corner beads are used to finish outside corners, J beads and stop beads can be used to prevent moisture from wicking into the drywall or to give a straight edge to the wall where it butts up against an irregular surface.

These beads can also be used to create some very unique architectural features such as recessed or protruding offsets. Expansion beads are rarely used in residential homes because they leave a visible line in the surface however when it comes to very large ceilings and walls you run the risk of cracks developing without their use. These cracks appear because your house swells and shrinks with temperature and humidity changes and different the materials that make up your house will do so at differently.

Its your call do you want to override the architects orders of a nice intentional uniform indentation in your large ceiling or do you want to run the risk of an ugly crack. Wood Lathe are the thin wood strips used in the old horsehair plaster.

Wood lathe is still used in plastering, but its use is usually reserved for homes and building that are listed as a historical land mark. This is required in order to maintain the legal standing of historical landmark. Life expectancy is defined as the time it takes for the product to deteriorate to the point where the loss of aesthetics can be observed. The life expectancy of sheetrock and joint compound finished surfaces is much shorter then it is with blueboard and plaster.

The main reasons for the differences in life expectancy is that joint compound has a very low tensile strength, is very susceptible to moisture and lets face it you the majority of the wall is nothing more then paint covered paper unlike plasters.

The humidity in and outside of your house changes and these humidity changes will penetrate into your walls which cause swelling and shrinkage of the drywall and joint compounds.

Temperature changes also cause the different materials of your house to expand and contract at different rates. Over time this movement can cause screws and joints to start to show up.

Plaster walls on the other hand create a uniform surface of stone which is much stronger then paint covered paper. Safety: House fires, while rare are where the safety differences between joint compound and plaster come into play. One type of drywall are the Fire Rated Drywalls, these are require in garages and on walls and ceilings that abut adjacent apartments, or common areas such as halls between apartments. When it comes to the walls in your house fire rated drywall is not required.

Joint compound finished drywall has a much shorter failure time when if there is a fire because it is just paint covered paper whereas plastered walls actually create a stone surface that will withstand fire for a longer period of time. The use of Kal-Kote base coat over half inch blueboard half inch thick drywall is what is used in a houses interior walls will provide the same fire rating as the thicker fire coded sheetrock.