Trusted structural calculations for extensions, lofts, and renovations across Sefton.
Based in Manchester, with engineers around the country for site visits. We've worked extensively across Merseyside and know Sefton well — the Victorian → Contemporary Large suburban detached/semis, Victorian terraces, coastal properties, the party wall situations that come with them.
More importantly, we know how Sefton 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 Sefton, and has delivered 9,000+ projects across England and Wales since 2012.
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 Sefton. Tell us about your project and you get a clear, fixed-fee quote before you commit.
Yes, we have extensive experience with properties along the Sefton coast. We understand the specific structural requirements related to sandy ground and exposure to the elements.
The sandy soils and potential for peat in areas like Formby mean that standard foundations are not always suitable. We often specify wider or deeper foundations to ensure stability.
On a full plans application, Sefton 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 cover all of Sefton, including Southport, Formby, Crosby, Maghull, and Bootle, and you choose your delivery date.
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 Sefton's unique characteristics helps us deliver precise structural solutions.
Local knowledge makes all the difference in structural engineering. Our team has in-depth understanding of Merseyside’s diverse property types, spanning Victorian → Contemporary with their typical Large suburban detached/semis, Victorian terraces, coastal properties. Every calculation we produce considers local building control expectations at Sefton Council, giving you confidence in approval.
Local Geology Expertise for Merseyside Projects
Every structural calculation must respond to site-specific ground conditions. In Merseyside, we commonly encounter Coastal blown sand, peat and alluvial deposits over mudstone, requiring particular foundation solutions. Characterised by extensive post-glacial deposits, including Blown Sand (dunes), peat, and marine alluvium, overlying the Mercia Mudstone Group. This geological understanding informs all our work, from simple extensions to complex structural alterations.
The area’s diverse building stock – Dominated by large detached and semi-detached homes, particularly along the coast – means varied structural challenges. From period properties around Antony Gormley’s ‘Another Place’ (Crosby), Southport Pier, Formby Red Squirrel Reserve to modern homes near A565 Coastal Road, Merseyrail Northern Line (Southport & Ormskirk lines), we’ve engineered solutions across Merseyside.
Working regularly with Sefton Council means our calculations align with their expectations. We’ve built a track record of first-time approvals, saving you time and frustration.
Coverage Across Merseyside
Operating throughout Merseyside and surrounding areas (population: 275k), our services include:
• Loft conversion and roof extension calculations
• Extension designs – all configurations
• Internal structural alterations
• Steel beam and RSJ specifications
• Foundation and underpinning calculations
Get Your Merseyside Structural Calculations Quote
Ready to start your project? Contact PorthouseDean today for a competitive quote on structural calculations in Merseyside. You’ll get a clear, fixed-price quotation before you commit.
Send us your plans and you'll have a clear, fixed price before you commit. Or give us a call.