A retractable ladder is a space-saving solution for access to roofs, lofts and technical areas. To ensure the ladder fits correctly, it must be coordinated with the structural opening, ceiling height, available installation space and any access hatch.
This guide explains which measurements are required and highlights common mistakes to avoid when specifying a retractable ZIP ladder.
Which ZIP ladder should you choose?
The ZIP range includes several retractable ladder models for commercial and public buildings. It is important to specify the correct model, as the models are measured and configured in different ways.
| Model | Configuration | Information to confirm |
|---|---|---|
| ZIP4–ZIP7 | The ladder is selected first and then coordinated with the opening and any separate access hatch or lining. | Ladder model, opening dimensions, clear opening and whether a separate hatch is required. |
| ZIP8 | A made-to-measure complete unit with a ladder housing and internal hatch. | Structural opening, ceiling height, installation space and any optional features. |
Measurements required for ZIP8
Most delays during the quotation process occur when a measurement is simply described as an “opening”, without explaining which type of opening is meant.
The following measurements are used when specifying ZIP8:
| Reference | Measurement | Description | Common mistake |
|---|---|---|---|
| A | Structural opening length | The length of the opening in the building structure. | Providing the hatch or unit’s external dimensions instead. |
| B | Structural opening width | The width of the opening in the building structure. | Confusing the structural opening with the clear opening. |
| C | Floor-to-ceiling height | The height the ladder must be manufactured to suit. The reference point must be clearly stated. | Measuring only to the suspended ceiling. |
| D | Installation space depth | The available space above the ceiling line for the housing and folded ladder. | Failing to check for services and other obstructions. |
| E | Ladder housing height | The vertical depth of the ladder housing. | Failing to coordinate it with the ceiling build-up. |
| F | Backboard height | Optional component used for fixing or finishing around the opening. | Identifying the requirement too late in the project. |
| G | Backboard width | The width of the backboard in relation to the opening. | Allowing the backboard to clash with the hatch or surrounding finishes. |
The first reference should be described as the structural opening, meaning the opening formed in the building structure.
The ladder housing is normally manufactured slightly smaller than the structural opening to provide the installation tolerance required for fitting.
Structural opening or clear opening?
The structural opening and clear opening are not the same.
| Term | Meaning |
|---|---|
| Structural opening | The dimensions of the opening formed in the building structure. |
| Clear opening | The usable passage size after the frame, ladder housing and lining have been installed. |
| External dimensions | The total external dimensions of the ladder housing or complete unit. |
| Hatch size | An unclear term that may refer to the hatch leaf, frame or complete unit. |
Avoid describing a dimension only as an “opening size”. Always state whether the measurement refers to the structural opening or the clear opening.
Check the suspended ceiling and supporting structure
Where the ladder is installed within a suspended ceiling, two height measurements are normally required:
Height from finished floor level to the finished suspended ceiling.
Height from finished floor level to the underside of the supporting structure.
The ladder must be fixed to the supporting structure and not only to the suspended ceiling grid.
The depth of the floor or roof structure and any downstand beams should also be checked. If the structure is deeper than the ladder housing, an additional lining or extension may be required.
Check the installation space
The housing and folded ladder require sufficient space above the ceiling.
Common obstructions include:
Ventilation ducts
Cable trays
Pipework
Sprinkler systems
Lighting
Beams and other structural elements
The ladder position should therefore be coordinated before the services above the suspended ceiling are fully designed or installed.
Check the ladder deployment area
There must also be sufficient space below the opening when the ladder is deployed.
Check the following:
Corridor or room width
Door opening directions
Walls and fixed furniture
Escape and circulation routes
Clear headroom and safe landing space
The ladder must be able to open and be used safely without blocking a passageway or creating a trapping hazard.
Retractable or fixed ladder?
The choice of ladder should be based on how often the access point will be used and how much space is available.
| Ladder type | Best suited for | Points to consider |
|---|---|---|
| Retractable ladder | Occasional access where the floor area must remain clear. | Requires sufficient installation space and a safe deployment area. |
| Fixed vertical ladder | Permanent access points and regular access. | Additional fall protection may be required. |
| Inclined stair ladder | More frequent access and a more comfortable climbing angle. | Requires more floor space and sufficient clear headroom. |
A retractable ladder is primarily intended for occasional or infrequent use. Where access is required regularly, or where users need to carry tools or equipment, a fixed ladder or stair ladder may be more suitable.
Should the ladder be combined with a hatch?
ZIP8 is normally supplied as a complete unit with a ladder housing and internal hatch.
For ZIP4–ZIP7, a separate access hatch or roof hatch may be required. The following should be checked:
Hatch structural opening and clear opening
Hatch opening direction
Ladder position
Available installation space
Any requirements for fire resistance, insulation or weather tightness
Where the opening is located within a fire compartment boundary, the fire rating and installation details of the hatch must be verified for the specific project.
Information required for a quotation
To help us recommend the correct solution, the following information should be included in the enquiry:
| Information | Measurement or details |
|---|---|
| ZIP model | ZIP4–ZIP7, ZIP8 or another model |
| Structural opening length, A | _____ mm |
| Structural opening width, B | _____ mm |
| Floor-to-ceiling height, C | _____ mm |
| Installation space depth, D | _____ mm |
| Ladder housing height, E | Standard or project-specific requirement |
| Backboard, F and G | State whether required |
| Suspended ceiling | Yes or no |
| Height to supporting structure | _____ mm |
| Structural depth | _____ mm |
| Services and obstructions | Describe or mark on drawing |
| Deployment area | Corridor width, doors and other obstructions |
| Hatch | Internal hatch, roof hatch or specific requirements |
A dimensioned drawing or sketch showing measurements A, B, C and D should preferably be included.
Need help choosing the right retractable ladder?
Elkington can help you select and size a retractable ladder based on the project’s structural opening, ceiling height, installation space and intended use.
Send us a drawing or sketch together with information about suspended ceilings, structural depth, nearby services and any required hatch. This will help us identify a solution suited to the project conditions.
