Trading up the housing ladder to a home with more bedrooms is something homeowners have traditionally expected to do, often to accommodate a growing family. But just how much does it cost to buy that crucial extra room?

Our latest research using OnTheMarket data shows that the biggest percentage uplift in value is between a three- and a four-bedroom home, a move costing on average over £164,000. This hefty 63 per cent premium is far higher compared to the cost of trading from a four- to a five-bedroom house, where an additional bedroom costs an extra 45 per cent. For those on the first rung of the housing ladder, an additional £68,629, or 49 per cent, would be needed to upsize from a one- to a two-bedroom home; and nearly £77,000, or 38 per cent, to upsize from a two- to a three-bedroom property.

So what does this uplift to obtaining that precious fourth bedroom look like on a regional level? Perhaps unsurprisingly, buyers looking to make this upgrade in inner London* face the highest additional cost, at £388,000 for their fourth room, but in percentage terms this is the lowest across England and Wales at 43 per cent.

In contrast, buyers of homes located in the typically lower value markets of Wales and the North of England face lower additional costs in monetary terms, but the largest percentage uplift. An additional 70 per cent of capital is needed to make the move from a three- to a four-bedroom house, albeit a four-bedroom one will undoubtedly also come with more reception and outdoor space.

The map below shows how much, at a local authority level, buyers need to pay on average to trade up from a three-bedroom property to a four-bedroom one in England and Wales.

It highlights the higher additional costs required for buyers moving up the housing ladder in the more expensive, southern parts of England. Outside of London, for example, there are only two local authorities in the Midlands and the North where this additional cost is above £250,000, but there are 16 in the East and South East of the country.

Note: This data represents a sample of properties that are either for sale, under offer or sold STC and doesn’t represent the entire housing stock of a local authority. For this reason, some sample sizes for the median figures are low, particularly in areas where 3 and 4 bed properties are less prevalent and may therefore distort the price difference between the two sizes of home.

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