Expert structural calculations for extensions, lofts, and renovations in Tonbridge and Malling, Kent.
Based in Manchester, with engineers around the country for site visits. We've worked extensively across Kent and know Tonbridge and Malling well — the Medieval → modern Brick semis, timber cottages, the party wall situations that come with them.
More importantly, we know how Tonbridge & Malling Borough Council’s building control team operates and we write our calculations to match. That saves time on site and avoids queries coming back.
PorthouseDean provides structural engineering for extensions, knock-throughs, loft conversions, and two-storey extensions in Tonbridge and Malling. With 220+ calculations completed across Kent, our engineers understand the area's Medieval → modern Brick semis, timber cottages properties, ensuring every design accounts for local building characteristics and London Clay ground conditions. Our most recent project in the area was a single storey extension completed in Dec 2025.
The calculations and drawings are ours. So are the things around them that usually land on you: a date you can plan around, one place where everyone sees the same documents, and the change of mind nobody priced for. More than 9,000 projects since 2012 have run through the same process, from a single wall removal to a whole new build.
Every job runs through the same process, so every customer gets the same three answers.
Tell us about the project and we’ll tell you the price and the steps that follow. No hourly rate. If the job changes, there is a free change request on every job.
Pick how fast you need it, and pay less if you can wait. You get a date to work back from.
Never wonder where it’s up to — just look. Your project hub shows what is happening now, what is next and anything we need from you, with your drawings, documents and invoice alongside. Share it directly with everyone involved in your project.
Building control gets the calculations. Your builder gets the contractor pack. If either of them has a question about the structure, it comes to us, not to you. How we check and what the process looks like.
No extras for building control queries.
A fixed price before you commit. No obligation, no chasing.
It depends on the size and complexity of your project, so we don't publish a price range for Tonbridge and Malling. Tell us about your project and you get a clear, fixed-fee quote before you commit.
Sure, we have worked on a wide variety of Tonbridge and Malling's Medieval - modern properties. Our engineers aim to understand the specific requirements of your property from Brick semis, timber cottages construction, ensuring calculations that respect the original structure while meeting modern standards.
Tonbridge and Malling typically has London Clay. Clay with flint seams. We factor these conditions into our foundation designs, which may affect the depth and type of foundations required.
On a full plans application, Tonbridge & Malling Borough Council has five weeks to decide, or longer if you both agree it in writing (regulation 14A of the Building Regulations 2010). On a building notice there is no plans decision: building control checks the work, and our calculations, as it goes. If they raise a question about the structure, your engineer answers it.
We provide structural calculations throughout Tonbridge and Malling and the surrounding Kent area. Our engineers regularly work on projects across the region, and you choose the delivery date that suits you.
If you're removing a wall, converting a loft, building an extension, or doing anything that affects the structure of your house — yes. Building control will require structural calculations before they sign off the work.
A virtual site visit is included in every quote — it's a chance to put a face to the name and talk through specific design requirements with your engineer. But we don't believe a physical visit is necessary for most residential projects. Working remotely allows us to be more economical while maintaining the same quality throughout. If your project does need a physical visit, we have engineers around the country who can arrange one.
On the date you choose when you book. The price follows the date: pick a later one and it costs less, or an earlier one if you need them sooner.
Every quote includes one free amendment because we know projects change — that's normal. Beyond that, we'll quote any further changes clearly so there are no surprises.
The quote's not the product — the project is. The moments that cost you come later: when building control query something, or your builder can't follow the drawings. That's why BC queries, an amendment and a virtual site visit are included — it's where projects actually succeed or fail.
Understanding Tonbridge and Malling's unique characteristics helps us deliver precise structural solutions.
Structural Engineering Excellence in Kent
Choosing the right structural engineer means finding someone who truly understands your area. We specialize in Kent properties, working regularly with everything from Medieval → modern homes built with Brick semis, timber cottages. This local expertise means our designs are written to satisfy Tonbridge & Malling Borough Council building regulations.
Successful structural projects begin with proper foundation design. Kent’s typical London Clay presents specific engineering requirements. Clay with flint seams We incorporate this geological knowledge throughout our calculations, ensuring safe, durable foundations for extensions, conversions, and renovations.
Riverside cottages, suburban semis This diversity means we’ve developed expertise across all property types – whether you’re extending a period property near Tonbridge Castle; Lullingstone Roman Villa or renovating a modern home with easy access to Southeastern; A21.
We maintain strong working relationships with Tonbridge & Malling Borough Council building control, streamlining approvals for your project. Our calculations are approved by building control, or you get a refund.
Structural Engineering Services Throughout Kent
We provide comprehensive structural calculations across Kent (population: 136 k), covering:
• Loft conversions and dormer additions
• Rear extensions – single and double storey
• Side and wrap-around extensions
• Load-bearing wall removal calculations
• Foundation designs and underpinning assessments
Request Your Free Kent Structural Engineering Quote
Starting your project? Get in touch with PorthouseDean for structural calculation pricing in Kent. You’ll have a detailed, fixed-fee quotation before you commit.
Send us your plans and you'll have a clear, fixed price before you commit. Or give us a call.