Understanding Wall Construction Types: External Walls

Cavity Walls: Your Two-Layer Protection

Imagine a cavity wall as having two distinct layers, or "skins," made from masonry. The outer layer you see can be either brickwork or blockwork, while the inner layer is typically blockwork. There's a gap between these two layers – that's your 'cavity' – and its exact width will change depending on the insulation material you plan to use.

For your cavity wall to work effectively and stay structurally sound, you need to pay attention to two key areas:

• Wall Ties: To prevent the two separate skins from pulling apart, you must secure them together using robust stainless steel, corrosion-resistant wall ties. Make sure to place these at the correct intervals throughout the wall.

• Moisture Protection: It’s vital to stop any moisture that enters the cavity from reaching the inside of your building. You achieve this at the bottom of the cavity in one of two ways: either you fill it with a lean-mixed concrete that slopes towards the external skin, or you install a cavity tray that also slants outwards. Both methods ensure any water is safely channelled away.

Solid Walls: A Single Layer Approach

Unlike a cavity wall, a solid wall consists of just a single layer of masonry, which could be brickwork or blockwork. If you're building with solid masonry walls, you might find it more difficult to achieve the high thermal insulation standards required for modern buildings.

However, you can still meet these stringent requirements with solid blockwork constructions, but only if you incorporate additional insulation products and apply appropriate surface finishes.

Upgrading Your Existing Walls During Conversions

When you're undertaking a building conversion or renovation, a crucial step is to thoroughly inspect the existing external walls. You must verify they are fully adequate for their new intended purpose. Your assessment needs to cover the following:

• Structural Strength (Loading): Will the walls be strong enough to support any new weight or loads you introduce?

• Weather and Damp Resistance: Do they still effectively protect against the weather, and is their damp-proofing robust enough?

• Thermal Performance ('Thermal Elements'): Do these walls meet the current insulation standards and requirements?

If your checks reveal any shortcomings, you'll likely need to upgrade the walls. This might involve constructing a new internal layer, potentially using lightweight studwork. When you add any new skin, meticulous planning for its base is essential. This ensures you establish effective damp-proofing arrangements and protect any new timber elements from moisture.