Should You Repair or Replace Lath & Plaster?

Lath and plaster is a method of plastering interior walls which was used widely from the 17th century, all the way up until the mid-20th century. Here’s a look at what the technique involves, and what the advantages and issues of this type of plasterwork are.

If you have a period home that is over 70 years old, then chances are that it will have lath and plaster walls, unless it has been renovated with more modern techniques.

Laths are thin strips of timber which are built as a framework over the wall, with gapping of about 6mm. The laths are then coated in three layers of plaster. The first layer filled the gaps between the laths, whilst the second layer of about 6mm thickness covered the laths. The third and final layer was the smoothest layer to provide a surface for painting or paper.

The plaster was made up from a mixture of lime putty and sharp sand, sometimes with horse hair added into the mix. The third and final layer was made up with fine sand to give a smoother finish.

Because lath and plaster walls are found in older properties, they may not always be in great condition. If you have an period property with cracks or even chunks missing from the lath and plaster, you may be wondering whether to have it restored or whether to update it with a modern drywall plaster method.

However, it is often worth restoring the original wall if you can. This is because all the layers have some distinctive advantages over drywall plaster. Firstly, the thickness of the boards plus three coats of dense plaster provides a good level of thermal insulation, which helps to keep the heat in the house, and keep it out during hot weather.

Traditional plasterwork also provides a good level of soundproofing, so that you will notice less noise transference between different rooms in the house, or from any adjoining properties. It may also offer a better level of fire protection. Finally, the slightly uneven texture when compared to drywall panels can add character to a home.

The age of the plasterwork does mean that it needs regular inspections to check that it is not deteriorating. If you do notice any problem areas, it’s important to deal with them straight away. The good news is that it is possible to repair and restore lath and plaster walls to its original condition.

It’s even possible to commission a newbuild with modern lath and plaster walls, which tend to be made from clay, lime, and acrylics, and won’t contain any horsehair. This is increasingly being seen as a more sustainable option to drywall, because it is more durable, damp resistant, and provides a better level of insulation and soundproofing.

All these advantages mean that you won’t have to invest in further treatments for your walls. However, traditional plastering should only be carried out by building restoration professionals, because of the specialist nature of the materials and methods involved.