Calculations by a chartered structural engineer for residential work across the borough: beams and lintels, pad foundations, removed walls, upgraded loft floors, underpinning. Eurocode-compliant, and ready to hand to Building Control.
Whenever a load path changes — removing a wall, forming an opening, or cutting rafters for a dormer. Croydon’s Datahub set records 3,641 rear dormer applications, and every one of those roofs needed trimming calculations. Building control decides a full plans application in five weeks.
| Work | Calculations required | Basis |
|---|---|---|
| Removing a load-bearing wall | Yes | Beam sizing and padstones, Part A |
| Forming an opening in a rear wall | Yes | Lintel or goalpost frame, Part A |
| Rear dormer cutting roof rafters | Yes | Trimming and new floor loading, Part A |
| Loft floor to habitable use | Yes | 1.5 kN/m² imposed load, BS EN 1991-1-1 |
| Croydon rear dormer applications | 3,641 | 77% approved |
| Full plans decision period | 5 weeks, or 2 months by agreement | Building Regulations 2010, reg 14 |
Sources: the Building Regulations 2010 (as amended), Schedule 1 Part A and regulation 14; Approved Document A; BS EN 1991-1-1 with its UK National Annex; the Datahub row from the Planning London Datahub, retrieved 15 August 2026, phrase-matched and comparable within Croydon only. Read at 1 September 2026. Calculations go to building control, never to planning: a Croydon planning approval says nothing about whether the structure has been checked.
A structural calculations package in Croydon, where the stock is largely Victorian villas in Upper Norwood and Crystal Palace; Edwardian terraces in Thornton Heath and Selhurst; 1930s semi-detached in Purley and Coulsdon; post-war in Croydon central, is the full measured-survey-to-submission drawing set London Borough of Croydon needs in order to determine an application: existing and proposed plans, elevations and sections at 1:100 and 1:50, a location and site plan, and the supporting statements the case officer asks for.
Prepared and reviewed by the architectural technologist team at Architectural Drawings London — CIAT Affiliate, professional indemnity insured.Last reviewed 2026-08-03.
Chartered structural engineer calculations for every residential intervention in Croydon — steel beams, lintels, pad foundations, wall removals, loft floor joists, underpinning. Eurocode-compliant, Building Control-ready.
Housing stock in Croydon: Victorian villas in Upper Norwood and Crystal Palace; Edwardian terraces in Thornton Heath and Selhurst; 1930s semi-detached in Purley and Coulsdon; post-war in Croydon central.
Character: Large, mixed-density outer borough; permissive in outer areas; heritage controls in conservation pockets; major regeneration in central Croydon.
RSJ and padstone design for the moment a Croydon kitchen wall comes out, two reception rooms become one, or a whole ground floor opens up end to end.
Ridge beams, purlin support, dormer framing, and the floor joist upgrade that turns a Croydon loft into a habitable room instead of a storage space.
Pad, strip or trench-fill foundations designed against what is genuinely under the plot, the trees standing near it and the line the drains take. Croydon spreads over 8,649 hectares and the ground beneath it is nothing like uniform from Coulsdon to Thornton Heath.
New window and door openings need a lintel, whether it is steel, concrete or timber, and the bearing at each end is calculated on the sheet rather than assumed off it.
Basement work: the underpinning sequence pin by pin, the reinforced concrete slab, and retaining wall calculations for the ground pressure each buried face has to hold back.
Nothing leaves here unsigned: CEng MIStructE or MICE on the front of every calculation set. Building Control bodies in Croydon and outside it accept the work on the strength of that.
Single planning or regs submission.
Planning + building regs + structural.
Listed, conservation, complex sites.
Move the controls for an indicative figure. It anchors your budget — it is not a quote. Every project is priced after a site survey.
Build costs are separate and quoted by your contractor. See our published fees.
Each Croydon district we work in, set against its prevailing house type and whichever council ends up validating the engineering. Charges in this table are statutory England rates for 2026, and none of them is our fee.
| Postcode | Area | Dominant stock | What it means for a structural calculation package |
|---|---|---|---|
| CR2 | South Croydon | Victorian villas around Upper Norwood and Crystal Palace; Edwardian terraces through Thornton Heath and Selhurst; interwar semis at Purley and Coulsdon; post-war blocks in the centre. Each type carries its load a different way, which is why a beam schedule here is never generic. | South Croydon occupies CR2 by itself, so a structural package goes to this borough and the CR2 designation map applies to whatever it supports. |
| CR5 | Coulsdon | 1930s semi-detached | The regime here is building control, not planning. An engineer's calculations go to a building control body — Croydon's team or a Registered Building Control Approver — for checking against Part A. Coulsdon sits on the chalk of the North Downs and CR5 plots often slope, so stepped and retaining foundations enter the design more than they do further north. |
| CR7 | Thornton Heath | Edwardian terraces | Thornton Heath fills CR7, so every structural package raised from a CR7 address is validated by Croydon Council under its own policies. |
| CR8 | Purley | 1930s semi-detached, Edwardian villas | CR8 is Purley alone. Croydon handles the structural package, with the CR8 conservation-area boundaries in play on any work that shows externally. |
| SE20 | Anerley / Penge | Victorian and Edwardian terraces | SE20 takes in Anerley and Penge and is shared between Bromley and Croydon, so an address there is read against two policies maps rather than one. |
| SW16 | Streatham / Norbury | Edwardian terraces, post-war flats | SW16 is the most divided of the lot. A Streatham or Norbury address can sit in any of four boroughs — Lambeth, Wandsworth, Merton or Croydon — so establish the authority before a structural package goes in anywhere. |
| SE19 | Upper Norwood / Crystal Palace | Victorian villas, Edwardian terraces | An SE19 job in Upper Norwood or Crystal Palace may belong to this borough or to Lambeth: the district straddles the line, and the policies map settles it address by address. |
| SE25 | South Norwood / Selhurst | Victorian terraces | SE25 belongs wholly to Croydon, covering South Norwood and Selhurst, and the borough's own Local Plan governs a structural package raised there. |
Pitch, wall build-up and plot depth are one thing in Purley and quite another in Selhurst, and each of those differences lands somewhere in the calculation.
Conservation areas covering Croydon: Croydon Council runs 24, and Old Coulsdon, Purley, Shirley Park are the ones Croydon owners meet most. A structural calculation package inside a Croydon conservation area loses permitted development, so the Croydon submission is a householder application at £548 decided in 8 weeks — not a £249 prior approval decided in 6 weeks. In South Norwood a structural calculation package is judged on the street elevation first.
Croydon permitted development status: there is no borough-wide direction from Croydon Council, so a structural calculation package at a SE19 address is normally still permitted development. We certify that with a £274 Lawful Development Certificate rather than leaving a Croydon sale to argue it later.
The building fabric around Croydon: Victorian villas in Upper Norwood and Crystal Palace; Edwardian terraces in Thornton Heath and Selhurst; 1930s semi-detached in Purley and Coulsdon; post-war in Croydon central. Large, mixed-density outer borough; permissive in outer areas; heritage controls in conservation pockets; major regeneration in central Croydon. A structural calculation package in Croydon is scoped against that stock first, because it decides whether the scheme runs as permitted development, a £274 Lawful Development Certificate, or a full £548 application to Croydon Council.
Sources for this Croydon structural calculation package page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.
The engineering questions Croydon homeowners send us most often, answered plainly and with no quote attached to the answer.
Start a free quote →The fee tracks the intervention. The smallest package is one beam over one removed wall. Ridge beam, purlins, foundations and lintels together, for a whole loft or extension, is the larger one. Anything below ground, or across several storeys, is priced by itself. Chartered engineer sign-off sits inside all of them. See our fees.
Yes. Take a load-bearing wall out anywhere in Croydon and the calculations have to show that the new beam, and whatever holds each end of it up, take the load that wall was taking. Building Control will not sign the job off without a chartered engineer's signature underneath. Even a wall you are fairly sure is a partition is worth checking before the first brick moves.
Turnaround runs 1 to 2 weeks once the architectural drawings and the site measurements are both in front of us. Urgent Croydon jobs can take a 3 to 5 working day fast track for a small premium.
They are different documents. A structural survey inspects the building as it stands and writes up defects, movement, subsidence. Calculations do the opposite job — they design the new beam, the new foundation, the loft steelwork, and prove it carries the load. Most Croydon extension and loft projects want the second and never the first. Calculations are what we issue; if a condition report is what you were actually after, we can name a surveyor who does them.
Yes. Plenty of Croydon jobs arrive with architectural drawings already done elsewhere, and we calculate against those as they stand. Where you want the pair, the Complete package carries drawings and structural together for less than buying them apart.
If your property sits on a boundary, here are the neighbouring options.
Croydon does not wave larger householder extensions through. Of the 529 prior approval applications it determined for a deeper single-storey rear, only 155 — 29.3% — were told prior approval was not required, where the pooled London share is 61.9%. It refused 80 of them, 15.1%, against 24.9% across the capital (MHCLG planning statistics, retrieved 1 September 2026). So more of these get a considered decision here, and fewer of those decisions come back as no. Either way the beam still has to be designed, and one CIAT-affiliated team does that alongside the drawings.
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