Cavity and Cavity Wall DIY Projects

This page includes links to all of our Cavity and Cavity Wall DIY how to projects including advice on damp issues and fixes, vertical Dpc, insulation of cavities, cavity trays and lintels and pumped cavity walls. Browse through the below list and click on your chosen link to view the project information.

Available DIY How To Projects

Cavity wall construction began to replace solid wall construction for the main part in about 1890. From then on it very quickly became the preferred method of building house walls.

Section through a cavity wall showing insulation, cavity and wall ties

Section through a cavity wall showing insulation, cavity and wall ties

To tie the two skins of a cavity wall together the first wall ties were made of iron, steel or copper but as corrosion took hold ofer the years, these ties expanded with rust forcing the bricks apart and introducing cracks which = weakened the wall.

Stainless steel and galvanized ties were introduced increasing the life expectancy of a wall tie dramatically.

The principle of a cavity wall is that moisture in one wall cannot pass through a void into the other wall. However if the cavity becomes block or “bridged” it will allow water to travel from one skin to another. This must be avoided.

The problem with a cavity wall was that the inside skin of the cavity was very much thinner than the old thick wall this type of construction replaced. It was therefore easier for the heat inside the building to dissipate through the inside wall and get lost in the cavity. To overcome this, the cavities started to be built with cavity insulation inside and this is still the case today.

The standard width of a cavity used to be 50mm but with the addition of cavity insulation it is now not unusual to see cavities of 100mm containing 50mm of insulation and leaving a 50mm air gap. This of course (providing the void is not bridged with mortar and the wall ties are sloping from in to out, covers all angles by keeping the heat in while keeping the water out.

Tray DPCs can be introduced to ensure any water in the cavity is directed to the outside wall where it can escape through weep holes.

There is some good information on types of bricks and blocks, laying bricks and blocks and how to create the most suitable cavity wall in our pages. If you want to find out how to become a bricklayer and learn to build cavity walls visit the national career service website