Not sure what to submit? This guide explains exactly what we need for each type of project — so we can get started on your calculations straight away.
The quality and clarity of the drawings you send directly affects how quickly we can produce your structural calculations. Clear, dimensioned drawings with a scale bar = faster turnaround.
If your drawings are unclear or missing key information, we may need to come back to you with questions — which adds time. The checklist below tells you exactly what to include for each project type.
Don't have professional drawings yet? That's fine — send us what you have and we'll let you know what else is needed when we review your project.
Rear extension, side extension, wraparound or double-storey extension
A dimensioned plan showing the current layout of the house — particularly the area where the extension will be built. Must include wall positions, door and window locations, and overall dimensions.
The new layout showing the extension in context with the existing house. Must be drawn to scale or include a scale bar and key dimensions.
External views of the extension showing roof pitch, wall heights, window and door positions. Front, rear and side elevations as applicable.
Cross-section through the extension showing roof construction, floor build-up and any changes in level. Very useful for confirming structural details.
If your architect or designer has produced CAD files, sending these alongside the PDFs can significantly speed up the calculation process.
💡 Key detail: Make sure the drawings show the opening between the existing house and the new extension — this is where a steel beam will almost certainly be required, and we need to know the exact width and what is above it.
Velux, dormer, hip-to-gable or mansard loft conversion
Showing the current roof structure — rafter positions, ridge, purlins, existing joists and any load-bearing walls below. If you don't have this, a sketch with approximate dimensions is a starting point.
The new habitable space layout including staircase position, room layout, dormer location and any rooflights.
Showing the external appearance of the conversion and a cross-section through the new loft space with key heights and dimensions.
Photos taken inside the existing loft space showing the current timber structure — rafters, joists, purlins, ceiling ties. Very useful where existing drawings are not available.
💡 Key detail: Tell us where the new staircase will come up — this determines where the staircase opening is cut through the existing floor joists, which is one of the most important structural elements of a loft conversion.
Knocking through, creating open-plan spaces, steel beam installation
A dimensioned plan of the existing layout. Clearly mark or highlight the wall you want to remove — either on the drawing itself or describe it clearly in your message (e.g. "the wall between the kitchen and dining room on the ground floor").
Either a proposed floor plan showing the wall removed, or a clear description of what you want to achieve — for example "remove full wall to create open-plan kitchen/diner" or "create 2m wide opening in wall".
Photos of the wall to be removed from both sides, plus photos of the floor above (if accessible) and the room above. This helps us assess what is carried on the wall.
If the property has more than one storey, a plan of the floor(s) above the wall being removed helps us understand the full load path.
💡 Key detail: Tell us the full width of the opening you want to create, and whether you want a full wall removal or just an opening. This determines the size of steel beam required.
Fastest turnaround. If your architect has CAD files, always send these alongside the PDFs.
The standard format. Clear, scaled PDFs with dimensions and a scale bar are perfect.
Acceptable for photos and sketches. Not ideal for technical drawings — use PDF where possible.
Upload your drawings using our quote form and we'll review them and send you a fixed-price quote within 24 hours.
📋 Submit Your Drawings