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Top 5 Design Mistakes That Kill HMO Profitability
- Maine Blueprints
- Dec 10, 2025
- 3 min read
Maximising the profitability of a HMO isn’t just about buying well - it’s about designing smart. Poor design decisions can quickly erode rentability, create compliance headaches, and limit your ability to achieve top-tier room rates.
Here are the top five design mistakes that quietly (and sometimes catastrophically) reduce HMO profitability and how you can avoid them.
1. Poor Space Planning That Wastes Rentable Area
Many HMOs lose money before construction even begins. Why? Because the layout and designs simply don’t maximise usable space.
Common issues include:
Oversized communal areas
Awkward corridors eating into rentable space
Rooms that fall under minimum space standards
Inefficient bathroom / en suite placements
Result: fewer bedrooms, lower yields, and higher cost per unit.
How to avoid it: Early concept design and feasibility is able to highlight what is possible before money is spent on drawings or planning.
2. Ignoring Natural Light & Ventilation
Rooms that feel dark, cramped, or lack ventilation not only struggle to command premium rents, but they also increase tenant turnover.
Common mistakes:
Blocking windows during reconfiguration
Creating internal bedrooms without borrowing light
Poorly located kitchens or utility areas leading to odour or moisture issues
How to avoid it: A design-led feasibility will quickly identify where light can be improved and how to meet HMO standards strategically.
3. Not Designing for Future Compliance
HMO regulations are tightening each year. Designing only for “today’s” requirements leaves investors exposed to costly retrofits later.
Typical oversights include:
Non Compliance with Part B - Fire regulations
Non Compliance with the councils size standards
Non Compliance with Part E - Acoustic Regulations
Non Compliance with Part F - Ventilation regulations
EPC - SAP Calcs before build! A small sum of money for long term gains!
Non Compliance with Part L - Thermal upgrades including incoming EPC legislation
How to avoid it: Conduct a pre-acquisition feasibility to test layouts against current AND emerging compliance standards - before committing to purchase. Construction drawings are also key to avoid these mistakes.
4. Underestimating the Power of High-Quality Shared Spaces
Investors often prioritise squeezing in one more bedroom and lose sight of what tenants value most.
A poorly designed kitchen, tiny lounge, or awkward dining area can hurt both rental price and occupancy.
Why it matters:
High-quality communal spaces significantly increase:
Tenant satisfaction
Room rates
Length of stay
Overall demand
How to avoid it: Early-stage design support ensures shared spaces are positioned, sized, and styled to attract your ideal tenant demographic without sacrificing yield.
5. Missing Out on Commercial-to-Residential Potential
Many developers walk away from opportunities simply because they are unable to visualise what’s possible.
The mistake isn’t the property, it's the lack of strategy and vision before purchasing.
Common issues include:
Assuming planning won’t be possible
Not identifying how many units can actually fit
Misjudging costs or structural implications
Overlooking the building’s strengths
How to avoid it: A Desktop Study or Desktop + Viewing service provides clarity on viability, layout options, potential yield, and red flags all before you commit.
Protect Your HMO Profitability from Day One
The investors who scale profitably are the ones who get clarity early, not halfway through the project.
If you want to avoid costly mistakes, get expert design insights, and make acquisition decisions with confidence, book a call with our team.
We will help you understand what’s possible, what’s risky, and what will give you the strongest long-term return.
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