Timber Rafters / Joists (Flat or Pitched)

Timber rafter and joist calculations for flat or pitched roofs.

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Timber Rafters / Joists (Flat or Pitched)
Name
Is the roof:
Selected Value: 30
How Old Is the Property (Slide the circle)
Is this calculation for
The total horizontal distance the joists or rafters span between their supporting walls or beams (measured in millimetres). Measure from inside face of support to inside face of support. (200 mm minimum - 5400 mm maximum)
The type of roof framing system (e.g. traditional cut timber roof, prefabricated trusses, or other system). This helps determine load paths and structural behaviour.
Roof covering type
Ceiling type
Is the roof supported by purlins or intermediate walls?
The horizontal distance from the inside face of the supporting wall to the first purlin, or between purlins if there is more than one. This helps determine intermediate roof support positions (measured in millimetres). (200 mm minimum - 5400 mm maximum)
Selected Value: 1
Please count all levels, including your basement and any converted loft spaces. (Slide the circle)
Please enter the angle of the roof's pitch in degrees.
End 1 support
End 2 support
Are there any heavy, concentrated loads (like a steel column or a chimney breast) bearing down on this wall from above?
Please describe any point loads you indicated above.
Optional
If you need to send files such as images, documents, or plans, we recommend using a secure file-sharing service such as Dropbox, Google Drive, or WeTransfer. After submitting the form, you can either include your link above or email it to info@engtechdesign.co.uk.
Price: £0.01
Timber Joists & Rafters Calculation – Roof Structure Design admin charge
Timber Joists & Rafters – Roof Structure Design. Delivered within 1‑3 business days. Press a payment button below to process your form .

Once submitted, your calculation will be reviewed by a qualified structural engineer and delivered within 1–3 business days.