Non-standard construction: how to assess house value

Start with the construction system, not a discount

The phrase “non-standard construction” covers too much ground to determine a house price. Establish the precise structure, build date and repair history before trying to compare value. A broad label cannot tell you whether a specific building has a defect or whether a particular lender will accept it.

For a home in Derry or Londonderry, record what is known and how it was established. Plans, a survey and professional repair records carry different information from a visual impression at a viewing. If the construction is uncertain, resolving that question may be more useful than requesting another online estimate based on the same incomplete details.

Keep three questions separate

The first question is physical: what is the building’s condition and what investigation or work is needed? The second is about the proposed transaction: what will the buyer’s lender and insurer require? The third is market value: how does the verified property compare with alternatives that relevant buyers could choose?

One answer does not settle all three. A mortgage valuation does not provide the same investigation as a detailed home survey. Equally, an older mortgage or a previous sale does not establish the outcome of a new application. Keep the professional advice attached to the question it actually answers.

Use lender evidence carefully

Lenders can distinguish between specific construction systems rather than treating every unusual building alike. Nationwide’s published criteria, for example, say that the exact construction name and year can affect its terms. This illustrates why accurate identification matters; it is not a universal rule or an indication that Nationwide has assessed your property.

Ask a mortgage adviser to check the relevant lender’s current position using the available documents. If further information is requested, record what is missing. Do not turn an initial query into a claim that the property cannot be financed. Nor should a preliminary indication be marketed as a guarantee that every buyer can obtain a mortgage.

Find comparisons that share the important characteristics

Prefer evidence with a similar construction, location and accommodation where possible. Then account for differences in condition and completed repairs. A conventional house on the same street may help establish the surrounding market but still require a substantial judgement about comparability.

Record whether the evidence is an asking price, an agreed figure or a confirmed completed sale. Avoid concluding that a construction type causes a particular discount from a single pair of listings. Different presentation, size or sale circumstances could explain the gap. Ask the valuer which part of the proposed range is supported directly and which part reflects limited evidence.

Treat repair evidence and expenditure separately

Where work has been completed, ask what the report or certificate covers, who issued it and whether further inspection is recommended. Keep the construction system, repair specification and dates together. A folder of invoices is useful, but the professional interpretation is what explains the relevance to the house being valued.

Money spent on repairs is not automatically added to value. Likewise, a quotation for possible work should not be deducted twice: once as a specific cost and again within a broad condition discount. Ask for a clear explanation of how the final appraisal accounts for known work, remaining uncertainty and the starting comparisons.

When to use professional valuation advice

An automated guide cannot verify a concealed structure or evaluate a repair certificate. Read the result as broad context while obtaining the property-specific advice needed for a purchase, sale or other formal purpose. RICS’s survey guidance can help you discuss an appropriate inspection with a surveyor; the scope should match the building.

Our mortgage valuation guide explains another important distinction in the process. You can start with a Derry house-value guide and review how the estimate is produced, but a more detailed professional assessment is the useful next step when construction is a material uncertainty.

Related guide: mortgage valuation guide.

Explore: Derry house-value guide.

How it works: how the estimate is produced.