HMO and Block of Flats Valuations: What Every Property Investor Needs to Know

Valuations are one of the most misunderstood parts of the investment property process. When they go well, nobody thinks about them. When they do not, and the number comes back lower than expected, the frustration is real. Understanding how valuers approach complex investment properties, particularly HMOs and multi-unit freehold blocks, means you can plan more accurately and avoid expensive surprises.

The Investment Method and Why It Matters

For standard residential properties, the comparison method dominates. Look at what similar properties nearby have sold for, adjust for condition and location, and arrive at a value. Clean and straightforward.

For HMOs and blocks of flats, the investment method comes into play. This takes the net rental income, applies a yield percentage, and derives a capital value. A property producing £60,000 gross income per year at a 10% yield implies a value of £600,000.

The yield figure is everything in this calculation, and it is location-specific, market-specific, and evidence-dependent. In Cardiff, current HMO yields broadly sit around 9.5 to 10%. In Swansea, slightly above that range, around 10 to 10.5%. These are not permanent numbers. They shift with market conditions, local supply and demand, and the quality of the asset.

Worth noting: a lower yield means a higher value. A property at a 9.5% yield is worth more than the same income at a 10.5% yield. This is the direction you want yields to move if you are refinancing.

The C3 Cross-Check and Why It Matters for Small HMOs

Here is the nuance that catches investors out regularly. On a small HMO of three to six bedrooms, lenders and their valuers will not simply accept the investment method headline figure without checking it against the C3 residential value of the same property.

The reason is simple. If a terrace house costs £300,000 to buy and £50,000 to convert to a six-bed HMO, but the investment method produces a value of £600,000, why would someone not just buy the house next door for £300,000 and do the same? That arbitrage would theoretically cap the uplift unless there is a genuine barrier to replication.

Article 4 is that barrier in Wales and in many English city centres. Where planning permission is required for HMO conversion and most areas are at saturation point for new approvals, the premium can be sustained. Where there is no Article 4 and no planning requirement, the investment premium is much harder to justify.

Shorebrook Bank publishes explicit guidance on how they expect HMOs to be valued, and it is useful context. In non-Article 4 areas, small HMOs are expected to be valued on a C3 comparable basis. Only in Article 4 areas, where the HMO use is genuinely protected by planning constraint, is an investment approach accepted, and even then it should be cross-checked against C3 values.

For larger HMOs of seven or more bedrooms, which require planning regardless of Article 4, an investment approach is generally accepted subject to reliable comparable yield evidence being available.

The Practical Implication: What Yields Should You Use?

This is the question investors ask most often. What yield should I put into my refinance model?

The honest answer is that you should speak to a local valuer before you commit to your numbers. A valuer who actively values HMOs in the specific area where your property is located will be able to tell you where yields have been sitting in recent transactions. That is far more reliable than using a round number because it seems sensible.

If you are planning a buy-refurbish-refinance HMO strategy in Cardiff, calling a firm like Certus and having a five-minute conversation about where the market sits in your specific postcode could save you from entering a deal at assumptions that the valuation will not support. Valuers are generally happy to have that conversation. They are not going to tell you exactly what your property will be worth, because they have not seen it. But they can tell you where the market is.

Multi-Unit Freehold Blocks and the Aggregate Question

Blocks of flats present a different but equally important set of valuation issues. The question is whether a block should be valued as a single investment lot or as the aggregate of its individual unit values.

The aggregate figure, the sum of what each flat would sell for individually, is usually higher. This is what investors want the lender to lend against. The investment or single-block figure is lower, reflecting the discount a buyer would expect for taking on an entire block rather than a single flat.

Lenders care deeply about which figure they are lending against, because in a default and repossession scenario, their ability to recover their debt quickly depends on how easily the asset can be sold. An investor wanting to wait for individual flat sales is one thing. A lender who needs to recover debt within a defined timescale cannot afford to wait.

Whether an aggregate valuation is appropriate depends on the local market. In a strong city centre location with good demand, selling a small block of six flats individually within a six-month window might be plausible. For a block of 29 flats in a secondary location, the market simply cannot absorb that volume in a realistic timeframe, and the aggregate value is not a number that reflects what the lender could actually achieve.

The practical implication: do not base your refinance model on the aggregate value of a block without having a conversation with a local valuer first. If the market will not support individual sales at pace, the lender will not lend against those individual figures.

Valuation Packs: What Helps and What Does Not

Providing a valuation pack to the surveyor is worthwhile. Before-and-after photographs showing the refurbishment work, a schedule of works and costs, tenancy information, EPC certificates, floor plans. These make the valuer's job easier and reduce the risk of delays caused by chasing information.

What does not help is including a pre-prepared valuation with your own yield calculations and the comparable evidence you have selected to support your expected number. Valuers will source their own evidence. The impression created by trying to tell them how to value the property is not a positive one.

Challenging a Valuation

If the number comes back lower than expected, there are very few legitimate grounds for challenge. Disagreeing with the methodology is difficult because the valuer's professional judgement on methodology is exactly what you are paying for. Presenting comparable evidence you found on Rightmove of asking prices for properties that have not sold is not a challenge.

The only challenge likely to produce a different outcome is identifying a material error. A measurement mistake. A factual error about the property. Something the valuer did not have access to and that would genuinely change their assessment.

If you believe there has been a genuine error, that conversation is worth having. If you simply feel the number should be higher, the energy is better spent working out whether the deal still works at the number that came back.

If you want to discuss how a valuation is likely to approach your specific property, or want to understand what a realistic refinance value looks like before you commit to a deal, get in touch via our contact form and we can talk through it with you.