Bridging Over a Conservatory: Why It Costs Extra

If a conservatory, porch, flat-roof extension or bay window sits between the ground and the wall you need to reach, the scaffold cannot simply stand on the floor. It has to span the obstruction, and that span is what you are paying extra for.

What bridging actually involves

A bridged scaffold carries the load across the obstruction on beams, usually aluminium or steel lattice beams, supported by standards either side. The scaffold above then sits on those beams rather than on the ground.

That means:

• Heavier components. Beams are hire items in their own right and cost more than tubes.
• More labour. Setting and levelling beams is slower and more skilled than building off flat ground.
• Load calculations. The beam span, the load above and the support points all have to work. On larger spans this needs a design, and a design costs money.
• Sometimes a tied structure. Bridged sections often need additional ties into the building for stability.

What it costs

For a typical domestic conservatory or porch, expect £200 to £800 on top of the base scaffold, most commonly around £450.

The variables:

• Span. Up to about 4 m is routine. Beyond that, cost climbs quickly.
• Load above. A single working lift for gutter work is cheaper to support than three lifts for a re-roof.
• Design requirement. Anything outside a contractor’s standard configuration will need a scaffold design from a qualified engineer, typically £150 to £400 on its own.

Can the conservatory take the weight instead?

No. It is worth stating plainly because people ask: a domestic conservatory roof is not a structural platform and scaffolders will not build off one. Neither will they generally accept a flat-roof extension without checking what is underneath it.

If someone offers to stand a scaffold on your conservatory roof, that is a firm to walk away from.

Alternatives worth considering

• Work from the other side. If the job allows access from a different elevation, you may avoid the bridge entirely.
• Temporary removal. For a lightweight lean-to or a small porch canopy, removing and refitting it is occasionally cheaper than bridging. Rare, but worth a question.
• A tower inside. For localised work above a conservatory, a single gutter joint for example, a tower on the far side with a reach may be sufficient.

Tell the scaffolder early

Bridging is the most common cause of a revised quote on the day of erection. A scaffolder quoting from a photograph or a phone description may not realise the conservatory is there, arrive with standard components, and have to re-quote on site.

Mention any conservatory, porch, bay, extension, oil tank, manhole or sloping ground when you first make contact. It costs you nothing and it prevents the most common day-one surprise.

Get a realistic range for your property by entering your frontage, height, coverage and hire period. Every cost component is itemised, which is what lets you see why one quote is dearer than another.