Building Knowledge,
Practical Advice
Expert articles on extensions, conversions, planning permission, and property maintenance — written by TCM's team with 15+ years on London sites.
7 Costly House Extension Mistakes London Homeowners Make (And How to Avoid Them)
Most house extension projects that go over budget or over time share the same root causes. After 15 years building extensions across London and Hertfordshire, we have seen the same errors repeat themselves. Here is what to watch for before you break ground.
How Long Does a Loft Conversion Take? A Week-by-Week Timeline
A dormer loft conversion typically takes 8–12 weeks from start to finish. But that figure hides a lot of variation. The type of conversion, the structural condition of your roof, and whether you need planning permission all affect the programme significantly.
The London Landlord's Maintenance Guide: What You Must Fix and When
Landlords in London face a specific set of legal obligations around property maintenance. The Homes (Fitness for Human Habitation) Act 2018 and the Landlord and Tenant Act 1985 set out clear duties. Failing to meet them exposes you to rent repayment orders, fines, and civil claims.
Loft Conversion vs House Extension: Which Adds More Value in 2025?
Two of the most popular ways to add space and value to a home — but they suit very different properties, budgets, and goals. This guide compares both options across cost, disruption, planning, and return on investment so you can make the right call for your specific situation.
Types of Loft Conversion Compared: Dormer, Hip-to-Gable, Mansard & Velux
Not all loft conversions are the same. The type that works best for your home depends on your roof structure, the space you need, your budget, and whether you need planning permission. This guide breaks down all four main types with costs, planning rules, and which properties suit each.
Should I Extend or Move? A Practical Guide for Hertfordshire Homeowners
Stamp duty, agent fees, and removal costs can add £30,000–£40,000 to the cost of moving. Before you put your house on the market, find out whether extending is the more financially sound option — and what your property can actually accommodate.
How to Choose a Builder in Hertfordshire: What to Check Before You Sign
The building industry is largely unregulated. Anyone can call themselves a builder. This guide covers the specific checks — insurance certificates, company registration, payment schedules, and contract terms — that will filter out unsuitable contractors before you commit.
How Much Does a House Extension Cost in Hertfordshire?
Accurate 2025 cost figures for every extension type — single-storey, double-storey, side return, wrap-around, and loft conversions — based on real TCM projects. Includes what drives costs up, what to include in your budget, and how to get a fixed-price quote.
Do I Need Planning Permission for a Loft Conversion?
A clear guide to permitted development rights for loft conversions in Hertfordshire and North London. Covers Velux, dormer, hip-to-gable, and mansard conversions, conservation areas, Article 4 directions, and listed buildings.
What Is a Structural Engineer and When Do I Need One?
A practical guide to the structural engineer's role in residential building projects — what they do, when their involvement is mandatory, what they produce, and what it costs in Hertfordshire and North London.
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