House Extensions: Installing Support Beams for Open-Plan Living

In modern UK home extensions, creating open-plan spaces often means removing internal load-bearing walls. To maintain structural integrity, a support beam - typically a steel RSJ - must replace the wall and safely carry loads from above. These changes require structural calculations by a qualified engineer and approval under Building Regulations (Part A).

When Are Support Beams Needed?

• Removing internal or external load-bearing walls

• Creating wide openings for bifold doors or new layouts

• Adding upper floors or supporting roof structures

• Installing heavy glazing or suspended features

Common Beam Types

• Steel RSJs (Universal Beams): Ideal for long, open spans

• Box Sections: For box frames with vertical posts

• Flitch Beams: Timber-steel hybrid for aesthetic or space-limited designs

• Glulam/Timber Beams: Used where fire protection or appearance is key

Key Design Considerations

A structural engineer will calculate:

• Span, beam depth, and deflection limits

• Dead/live loads (people, furniture, snow, etc.)

• End bearings: Beams must sit on solid walls with at least 150 mm bearing

• Padstones: Spread the load into the wall to prevent crushing

Installation Overview

1. Prop the structure safely

2. Cut the opening and prepare padstones

3. Lower and level the beam

4. Pack out and secure with wedges or shims

5. Remove props and finish with fire-rated boxing (typically 2-layer plasterboard)

Common Mistakes to Avoid

• Skipping structural calculations

• Poor or inadequate temporary propping

• Not using proper padstones or under-sizing them

• Failing to tie twin beams together

• Ignoring lateral loads (especially on external walls)

• Missing fireproofing requirements

Properly designed and installed support beams make open-plan living possible - without compromising the safety or longevity of your structure.

Get started on your project today

Beam Designs offers structural calculations suitable for Part A Building Regulation Submission from £85. Click 'get started' today to find out more.

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