How To Touch Up Plaster Walls

Plasters were once one of the most widely used building materials. Though it was mostly used as a coating material for interior walls, plasters also found their application as a decorating material for internal walls and ceilings. Available in powder form, plasters are made by mixing gypsum, lime, and sand with water. With the advent of drywall, the usage of plasters has decreased considerably over the years. 

Though not widely used these days, Plaster walls are often troublesome for those who live in old houses. Since most of the residents are not used to setting up plaster walls, they are clueless on how to touch up plaster walls. Often, even for minute issues, they look forward to specialists. 

Well not anymore! Here’s our guide on how to touch up plaster walls. We have addressed some of the common issues that are found in plaster walls and how to touch up them, all by yourself with minimal effort and time. 

Three kinds of issues are commonly found in plaster walls. They are
  1. Cracks on the walls
  2. Holes on the walls
  3. Wearing off of wood laths
We will now examine each of these in detail.

1. How to fix cracks on plaster walls

Plaster Walls are often prone to cracks. This happens primarily because the plaster and lath get degraded over time. Laths are frames used to form the foundation for plastering. Mainly two types of cracks are found in plaster walls. They are structural cracks and spider web cracks. Structural cracks happen when the plaster gets displaced or loosened from the wooden lath. Meanwhile, cracks that happen within the plaster due to the degrading of plaster are spider web cracks. The major differences between both these cracks are the gaps between the cracks and the length of the cracks.
To fix the structural cracks:
  1. Using a putty knife remove the loose and ragged plasters.
  2. Smoothen the area using the putty knife.
  3. Clean the surface using a cloth to remove any specks of dust
  4. Mix the freshly bought plaster with water and make it into a paste form
  5. Using a wallboard knife, apply the plaster in the crack. Make sure to fill the crack with an ample amount of plaster.
  6. Level the filled crack with the rest of the wall using a putty knife.
  7. Now allow the area to dry for a minimum of 24 hours.
  8. Sand the area with fine-grit sandpaper to remove any dust.

To fix spider web cracks
Since spider web cracks are smaller, you can use spackle to patch the cracks. Using a putty knife fill the cracks with spackle and level the surface. Sand the surface using sandpaper to remove specks of dust. 

2. How to fill holes in the plaster walls

Along with the degradation of plaster, holes on the walls can also happen due to the constant contact of any object like doorknobs, shelf doors, etc. To fix the holes,
  • First, remove the damaged plaster by chipping the plaster using a cold chisel and ball pen hammer. Make sure not to chip hard as it will damage the lath.
  • Smooth the inside edges of the hole with a utility knife.
  • Fill the hole with the plaster using a wallboard knife or putty knife. To prevent the lath and dry plaster from absorbing too much moisture from the freshly added plaster, it is recommended to brush the holes with a bonding agent using a paintbrush.
  • Once the holes are filled with plaster, leave it as such for some time. 
  • Now cross-scratch the surface of the newly added plaster using a putty knife or blade. Make sure to scratch the surface vertically or horizontally to make shallow grooves on the surface of the plaster. This is done to ensure proper bonding between the first and second coating of plaster.
  • Leave the plaster for around 24 hours
  • Now apply the second coat of plaster over the first coating. Before applying the second coat, make sure to dampen the surrounding area by spraying water.
  • After applying the second coating, leave it for drying
  • Sand the surface using fine-grit sandpaper for smoothing and removing dust.

3. How to repair the lath? 

Laths are wooden frames that serve as the foundation for plastering. Laths are prone to damage over time. Some of the common issues faced by laths are loosening of the laths, breaking of the wood, forming holes and dents on the surface, etc. 
In case of loosened lath, you can fix it by adding metal studs and screwing it with new screws. However, when applying new screws and metals, we should be careful not to break the woods. 
In case of broken wooden pieces, replace the same with a metal piece of the same length. It is recommended you use a metal piece instead of a wooden piece as wooden pieces can wear off over time. It is better to add extra studs to give support to the newly added piece. 
In case of holes, you can fill the same with wooden fillers or small pieces of toothpicks. Apply a layer of plastic adhesive tape over the hole to keep the filler or toothpick firm. You can apply plaster over the holes.

So that’s it! We have covered almost all of the major commonly seen issues in plaster walls that you can fix by yourself without any external help. Happy DIY!

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