Question 1

What is a lintel and why does it matter?

Accepted Answer

A **lintel** is a structural beam spanning the top of an opening — a door, window or archway — carrying the load of the wall above and transferring it to the masonry on either side.

**Why it is necessary.** Masonry is strong in compression but weak in bending, and it cannot span a gap. Without something to bridge the opening, the wall above would have nothing to sit on. The lintel takes that load and redirects it sideways into the surrounding structure.

**The bearing is critical.** A lintel must rest on solid masonry at each end by a specified minimum — commonly **150mm** for domestic openings, more for wider spans. Inadequate bearing concentrates load on a small area and causes failure, and it is a frequent defect in amateur work.

**Materials:** modern construction uses galvanised or stainless **steel** lintels, often with a built-in cavity tray to direct water outward. Older buildings use **stone**, **timber**, **brick arches** or **reinforced concrete**. Cavity walls need lintels supporting both leaves.

**Why they matter to a homeowner:**

**Failure shows above openings.** Stepped or diagonal cracking above a window or door, sagging brickwork, or a window frame becoming distorted are classic signs of a failing or absent lintel. This appears on surveys regularly.

**Old steel lintels corrode.** Rusting steel expands substantially as it oxidises, and that expansion cracks the surrounding masonry — sometimes called **cavity wall tie or lintel failure**. Galvanised lintels from certain eras are known problem cases.

**Timber lintels rot**, particularly where damp has reached them.

**They are frequently missing entirely.** Openings formed by previous owners without proper work often have no lintel or an inadequate one, which a survey may flag.

**Never cut a new opening without one.** Sizing depends on span, load and wall construction, and requires calculation plus Building Regulations approval.

Question 2

What is the difference between cavity wall and solid wall insulation?

Accepted Answer

The difference is what kind of wall you have, which determines both the method and the cost — and getting the diagnosis wrong is expensive. Which do you have? Homes built roughly from the 1920s

Question 3

How do I tell if a wall is load-bearing?

Accepted Answer

There is no completely reliable DIY test, and this is one of the few DIY questions where getting it wrong can collapse a building. The indicators below narrow it down; a structural engineer confirms

Question 4

How do you build a stud wall?

Accepted Answer

A timber or metal frame fixed between floor and ceiling, clad with plasterboard — straightforward in principle, and with several details that separate a solid wall from one that flexes and cracks.

Question 5

What is a party wall agreement, and when do you need one?

Accepted Answer

A formal procedure for notifying neighbours about work affecting a shared or adjoining structure, and agreeing how it will be done. In England and Wales it is a statutory process under the Party Wall

Question 6

Why do old houses need to breathe?

Accepted Answer

Because they were built without a damp-proof course or a cavity, and are designed to absorb moisture and release it again. Sealing them with modern materials traps that moisture inside the fabric,

Question 7

What is the difference between plaster, plasterboard, skim and render?

Accepted Answer

They are different materials and processes for finishing walls, and the terms are used interchangeably in a way that causes confusion when getting quotes. Plaster is the material — a gypsum-based mix

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