How should I inspect an old house?

Q: I’m keen to find a house to renovate, after undertaking a number of small-scale renovation projects. I’ve begun my initial search, but wondered if you could advise me as to how to survey the old houses I will be looking at. In particular, how should I go about it? Are there any key defects I should be looking out for? Obviously I will commission a full survey before making a purchase, but I’d appreciate any guidance which could help whilst I'm househunting for a renovation.

A: Most serious problems with old houses are found either at the top or at the bottom. Ideally the house will be vacant – preferably with the floors uncovered – but unfortunately this is often not the case. So before you undertake your own survey, explain to the owner or agent that you would like to spend some time looking around, specifically in the loft and at the drains. To this end, you’ll need to enquire as to whether there is a loft ladder. If there is not, take one with you, together with a good torch or lead light, a spirit level and also a few tools for lifting manhole covers.,/p>

When you arrive, try to assess the age and condition of roof covering. Modern pitched roofs are underfelted, with roof spaces ventilated and a good layer of insulation. This not the case with older homes, and old tile, stone slab or slate roofs could be near the end of their life. So look out for excessive amounts of tile or slate laminations in the loft. Flat roofs are usually bad news and need to be carefully checked. In the long run all flat roofs leak. And, small leaks which go undetected for some time can cause serious rot and other problems to timber below without necessarily showing through in the form of stains to the ceiling beneath.

Check the door and window opening. Are the cills level and sides plumb? Do the floors and ceilings slope? Are there any cracks in the walls or repairs where cracks have been filled? Any signs of leaning or bulging walls? Use a spirit level on floors, walls, cills and any other areas where you think there may have been movement. Most old buildings are not completely level or plumb. This can add to the charm, yet you do need to establish whether the movement is historic or active — active movement will be indicated by signs of recent cracking or old, repaired cracks which have opened up again. If you can, locate the damp-proof course (DPC) at the base of the walls. Normally the soil and paving outside, or internal floor level, should be at least 150mm (two brick courses) below the DPC. Check gutters and downpipes for blockages and leaks. Most old buildings have solid walls – in contrast to modern cavity construction – so any leakage of water down these walls outside can penetrate directly to the inside. And, if the DPC is bridged by high paving, serious damp problems may result. If you can, borrow a surveyor’s moisture meter – try it out beforehand so that you know how to detect a high damp reading – for use inside.

Woodworm and other timber defects are commonly found in old houses, meaning treatment and repairs may be required from time to time. Don’t worry if you find a few scattered woodworm holes in the roof or floor timbers. However, do check for bore dust and for any new holes. These indicate that the insects have flown to lay their eggs elsewhere in the house — the results of which can take a few years to appear.

With regard to cost, the most expensive defects to remedy are foundations in need of underpinning and roofs in need of recovering. However, you can also spend a lot of money on the bits in between, especially plasterwork and services — so make sure you have the electrics, gas, heating, plumbing and drainage checked before making that purchase.

Remember, it’s important to take care not to cause damage — so you may be restricted to touching and tapping walls and bouncing on floors in order to assess the condition of floor timbers, walls and ceiling plasterwork.

Finding Out About the Foundations

You won’t be able to inspect the foundations, but you can check the type of subsoil on which they rest by referring to the Geological Survey Map of the area (visit bgs.ac.uk). If the subsoil is a shrinkable clay, look out for any trees in close proximity to the main walls — roots extract water from clay, which can in turn cause serious damage. If the subsoil is sandy or gravelly, check the drains because leaking drains can wash away fine particles in this type of soil which can cause foundation movement.

Peter Glover is an experienced Chartered Surveyor working in London and author of Building Surveys: Seventh Edition (Elsevier Ltd, £24.99).

Further reading:

• How to Assess a Property for Renovation
• Old House Know How
• How to Finance Your Renovation