Checks before an offer

Checks have wildly different costs and wildly different chances of ending the conversation. Run them in the order of cost divided by likelihood of a deal-breaker: the ground, then what is planned nearby, then the building, then the money, then the legal position. There is no sense paying for a survey on a house you were always going to walk away from because of a flood map.

Flood is three separate questions

Rivers and sea, surface water, and reservoirs are mapped separately and a property can be clear on one and high on another. Surface water — water that cannot drain away fast enough in heavy rain — is the one people miss, because it affects places nowhere near a river. Check all of them, and check the immediate surroundings too: a house on a slight rise in a flooding street is still a house you cannot get to.

The consequence is financial as well as physical. A property with a flood history can be difficult or expensive to insure, and lenders take an interest in that, so a flood problem tends to arrive as a mortgage problem.

Ground stability

Historic mining, quarrying, landfill and made ground all show up in an environmental search later, but the free indicative maps will tell you whether to expect one. Clay soils bring subsidence risk, made worse by nearby trees and by a run of dry summers; a house on clay with a mature tree close to a corner deserves attention on the survey.

Trees and boundaries

Tree preservation orders and conservation-area status limit what you may do to trees in the garden, sometimes including ones causing the subsidence. Both are on the local authority's map. While you are there, look at where the boundaries actually run against the title plan, because fences move over decades and title plans do not.

A standard local authority search covers the property itself and, depending on the product, very little of what surrounds it. A field behind the garden with outline permission on it is not the seller's problem to disclose, and estate agents are not obliged to raise it.

Three places to look. The planning portal for the local authority, searched by area rather than by address, for live and recent applications within a few streets. The local plan, which is the document allocating land for development over the next ten to fifteen years and which shows intent long before any application exists. And the national infrastructure register, for the large schemes — roads, rail, energy, airports — that are consented centrally rather than locally and which can hang over an area for a decade without appearing in any local search.

That last category is worth real attention, because it moves slowly enough to be invisible and matters enough to affect both price and saleability. A proposal that is neither approved nor withdrawn is still a proposal a future buyer will find.

Age and construction type set the maintenance bill and, less obviously, the list of lenders willing to touch the property. Non-standard construction — concrete panel systems, steel frame, timber frame of certain eras, single-skin walls, thatch — narrows that list sharply, and a narrow list means a worse rate and a harder resale. It is a financing question before it is a building question, and it is answerable from the listing photographs and the EPC, both of which state wall and roof construction.

Other things worth establishing from the paperwork rather than the survey: whether extensions and loft conversions have building regulations completion certificates, whether the electrics have a recent condition report, the age of the boiler, and whether the roof covering is original. Any of these can be fine. The absence of paperwork for work that clearly happened is the thing to notice, because it becomes a legal indemnity question at the conveyancing stage.

On the EPC, read the recommendations page rather than the letter grade. It lists the measures with their estimated costs, which is a free, reasonably honest estimate of what the house needs.

Freehold means the land is yours. Leasehold means you own the right to occupy for a term, and the length remaining is the figure to find first. Below roughly eighty years, extending becomes materially more expensive, because the freeholder becomes entitled to a share of the value the extension creates — and lenders get uncomfortable well before the term gets short. A cheap leasehold flat with a short lease is not cheap; the discount is the cost of the extension, arriving later.

Also worth establishing early: whether access runs over land belonging to someone else, whether there are restrictive covenants limiting what may be built or run from the property, whether drainage connects to a public sewer or to a private system that becomes your maintenance obligation, and whether anything about the title is unregistered.

Comparing two properties is close to impossible when the information about each is in a different shape — a floor plan for one, a recollection for the other. The fix is dull and effective: one document per property, the same headings every time, in the same order, filled in as far as it will go and left explicitly blank where it will not.

Fifteen sections covers it: location and transport; the building; the ground; planning and infrastructure; running costs; the legal position; condition and works needed; the sold-price comparison; the chain; and a final honest section about whether you would actually be happy there on a wet Tuesday in February. Blanks are as informative as entries — three unanswered questions on a spreadsheet are much harder to ignore than three vague feelings.

In practice that last section rules out more houses than the survey does, and it is the only one that cannot be researched.