Buy-to-let landlords who neglect property maintenance could see tens of thousands of pounds wiped off the value of their investment, new research has revealed. A study by Rushbrook found the average owner in England stands to lose over £30,000 in capital value through poor upkeep, with that figure rising to almost £59,000 for landlords with London properties.

The building envelope, meaning the roof, guttering, external walls and windows, is where deterioration usually begins and where it’s most easily missed, according to George Edwards, Managing Director of Timberwise. Landlords should walk the exterior of the property at least twice a year, looking for slipped or missing roof tiles, blocked or leaking gutters, cracked render and any gaps around window and door frames. These are the entry points for water, and water is the single biggest cause of long-term structural damage.

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Look for signs of damp and timber decay

Inside the property, Edwards added that vulnerable areas such as bathrooms, kitchens, under-stairs cupboards and any rooms with external walls need attention. Watch for musty smells, discoloured or bubbling plaster, soft or spongy skirting boards and any give in floorboards. These are early warning signs of rising or penetrating damp, or in more serious cases, dry and wet rot, both of which can spread quickly and become far more expensive to put right the longer they’re left.

Test the essential systems

A basic assessment should also cover the property’s core systems, Edwards noted. That means checking that boilers, extractor fans and ventilation are working properly, that trickle vents aren’t painted shut, and that smoke and carbon monoxide alarms are tested and in date. Poor ventilation is a major contributor to condensation and damp, so it deserves as much attention as anything structural.

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Landlords should document every inspection with dated notes and photographs and use that record to build a rolling maintenance schedule rather than reacting only when a tenant reports a problem, Edwards explained. A programme like this doesn’t need to be complicated. What matters is consistency. Landlords who inspect regularly and act on what they find are the ones who protect both their tenants’ living conditions and the long-term value of their asset.