Why old houses need a different pair of eyes

A Georgian townhouse or a Victorian terrace was never built to a modern rulebook. It was built by craftsmen working to local materials, local weather and the knowledge of the day. That means the things that go wrong are different, and the things that look alarming often are not. A hairline crack in lime plaster may be nothing; a neat patch of cement pointing on a soft brick wall may be quietly destroying it.

So before you exchange contracts, you need a surveyor who genuinely understands period construction. Someone who knows why a solid nine-inch wall behaves differently from a cavity wall, why lime mortar needs to breathe, and why a 150-year-old roof timber can be perfectly sound while a five-year-old one rots.

Choosing the right level of survey

There is a straightforward rule: the older and more complicated the house, the more detailed the survey should be.

• The mortgage valuation is not a survey. It protects the lender, not you, and tells you almost nothing about condition.
• A mid-level survey suits a fairly standard house in reasonable order — perhaps post-1900, largely unaltered, with no obvious red flags.
• A full building survey is the sensible choice for anything pre-1900, listed, timber-framed, thatched, or previously extended and altered. It includes a much closer look at structure, roof voids, and defects.
• Specialist reports may be needed alongside it: a damp and timber survey, a structural engineer's appraisal, or advice from a conservation-accredited surveyor if the building is listed.

If the property is listed, ask about the seller's paperwork early. Unauthorised alterations can become your problem the moment you own it.

Damp, damp courses and the injected remedy trap

Most houses built before the late 1870s had no damp-proof course at all, and many built after that had a basic slate or bitumen one that has long since failed. That is normal. It does not automatically mean the house is damp.

What matters is why moisture is where it is. Genuine rising damp is rarer than the damp-proofing industry suggests; far more common causes are overflowing or leaking gutters, cracked downpipes, high ground levels bridging the damp course, blocked air bricks, and condensation from modern living habits.

Be wary of a survey that recommends an injected chemical damp-proof course in a solid wall without investigating drainage and ventilation first. In a traditional breathable wall, injecting a barrier can trap moisture and push the problem elsewhere — often upwards, where it damages plaster and timber. Watch for:

• External ground levels sitting above the internal floor level
• Cement render or hard pointing on soft, porous brickwork
• Tide marks, blown plaster, and salty staining low on internal walls
• Black mould in corners, behind furniture, and around windows — the signature of condensation

Roof timbers and rainwater goods

Ask your surveyor whether the roof void was actually entered. If not, that is a gap worth closing. Inside the loft, the questions are simple: are the timbers dry, and are they still doing their job?

Woodworm holes are almost universal in older roofs and often decades old. Fresh frass, soft timber and crumbling edges are the things to worry about. So are sagging purlins, split rafters, previous repairs, and any sign of wet rot (localised, often around a leak) or dry rot (a serious fungal problem that spreads through masonry and needs expert treatment).

Then look outside. In period property, rainwater goods cause more damage than almost anything else. Cast iron gutters that have rusted through, leaking hopper heads, blocked parapet and valley gutters, perished lead flashing around chimneys — all send water into walls and roof timbers year after year. A modest repair bill here can prevent a very large one later.

Walls, foundations and movement

Older houses move. They settle, they flex with the seasons, and they have usually been standing long enough to have done most of their settling already. The trick is telling historical movement from active movement.

Your surveyor will look at the pattern, width and direction of any cracking, whether it tapers, whether it reappears through later decoration, and whether door and window openings have distorted. Underpinning is very rarely the right answer for a period house, and it is expensive. More often the fix is straightforward: repairing drainage, removing a leaning tree, dealing with a leaking gutter, or reversing an inappropriate cement repair.

Watch out for cement render trapping moisture and spalling the brick beneath it, chimney breasts that have been removed without proper support, and bay windows that have begun to pull away from the main wall.

Services, alterations and the paperwork

Old wiring, lead water pipes, asbestos in textured coatings and outbuildings, and drainage that has never been mapped — these are all common in period property and all worth pricing before you commit.

Just as important is the paper trail. Look for building regulations approval on extensions, listed building consent on alterations, and evidence of who did the work and when. Ask specifically about:

• Any change of use, loft conversion, cellar tanking, or rear extension
• Whether windows and doors are original or replacements, and whether consent was needed
• Flood history and any insurance claims
• Boundary responsibilities, shared drains, and rights of way

An old house rewards patience. Commission the right survey, read it carefully, and treat it as a to-do list rather than a verdict. Nearly everything in a period property can be put right, provided you know what you are taking on before you take it on.