Key Takeaways Heritage buildings often include structural inconsistencies such as misaligned beams, out-of-tolerance risers, and incomplete steelwork that only become visible once construction finishes or fireproofing are removed. These variations directly affect lift position, gate alignment, and pit accuracy. Laser verification and early architectural coordination are two of the most effective ways Sesame Access prevents delays during hidden lift installations. Typical issues include beam offset discrepancies of 15–50 mm, pit depth variation of ±5–10 mm, and riser misalignment between upper and lower landings. Sesame’s experience in resolving these challenges ensures smooth installation, even within highly constrained heritage spaces.
Introduction Installing a hidden wheelchair platform lift inside a heritage building requires more than following architectural drawings. Once concrete is broken out and temporary coverings are removed, real-world conditions often differ significantly from the design intent. Beams twist, risers sit out of line, box sections land off-centre, and existing steelwork may be obscured by fireproofing. This article provides a people-first explanation of the most common on-site challenges encountered when installing concealed lifts in heritage buildings. It is informed by live field conditions captured during a technical inspection and complemented by guidance from our articles on Technical-pit-inspection-hidden-wheelchair-lift and Heritage-lift-installations, ensuring a complete understanding of the issues architects and contractors can expect.
Why Beam Alignment Variations Occur Beams in older buildings rarely match their documented positions. They can be twisted, offset, or partially hidden beneath fireproof spray. During heritage installations we frequently encounter:
- Beam offsets differing by 20–50 mm depending on height.
- Twisted beams causing the lift gate frame to sit out of tolerance.
- Obscured steelwork due to sprayed concrete that prevents accurate measurement until exposed.
These inconsistencies affect gate assemblies for solutions such as the Cavendish Platform Lift, where the gate pivot line and fixed posts depend on precise structural positioning. Early laser mapping and comparison against model geometry help identify necessary compensations before installation begins.
How Pit Accuracy Impacts Lift Operation A heritage lift pit is rarely cast perfectly. Even small deviations affect the lift carriage, travel path, and gate movement. Common issues include:
- Pit depth sitting 5–15 mm short of the drawing.
- Box sections positioned 60–100 mm away from the intended riser line.
- Upper pit steel missing or installed in the wrong sequence.
- Centreline deviations caused by offsets between datums and real-world conditions.
These variations can restrict usable space or cause the travel frame to foul on structural elements. In some cases, alternative steel channels must be introduced when space cannot accommodate full box sections. These scenarios are explained in more detail within our article on Technical Pit Inspection for Hidden Lifts.
Riser and Step Geometry Misalignment In many heritage buildings, upper and lower risers do not sit in line. Instead of following the drawing, the steps may be offset by 50–100 mm. This matters because:
- Gate swing paths rely on correct step nose geometry.
- The platform alignment must safely meet the landing.
- Riser misalignment can affect lift positioning by dozens of millimetres.
These findings also connect directly to the guidance in our article on Westminster-lift-solutions, which explains architects challenges.
Managing Floor Loading and Temporary Works A heritage installation often requires temporary works to safely move the lift into place. Hazards may include:
- Mezzanine floors that require temporary acrow props to manage concentrated point loads.
- Durbar steel decking that flexes under the platform’s caster loads.
- Space restrictions that limit the ability to use standard turning areas or load-spreading frames.
- Pit trim sequencing that must occur before the lift arrives, otherwise access is blocked.
This is particularly relevant when installing larger machines such as the Big Ben Electric Stairs, where turning and lowering into a heritage pit requires stable support that does not overstress the building’s existing floors.
Beam Twist, Offset Tolerances, and Real-World Measurement Laser checks during a site survey often reveal detailed discrepancies such as:
- Beam offset shifting from 30 mm at the top to 50 mm lower down.
- Riser-to-beam distances varying by 20 mm between levels.
- Pit edge centreline shifting by 10–20 mm due to casting irregularities.
These measurable deviations help architects understand why adjustments like shimming, gate post extensions, or pit steel rework may be required.
Internal Linking Cluster: Related Knowledge Hub Guidance To strengthen the learning path for architects and builders, this article complements:
- Technical Pit Inspection for Hidden Lifts
- Heritage Lift Installations
- Bespoke Lift Pit Depth Solutions
- Precision Lift Engineering
Together these pages form a connected set of resources that outline the full lifecycle of heritage lift planning, structural preparation, and installation execution.
FAQs How long does a heritage lift site survey typically take? A detailed survey usually takes 2–4 hours depending on access, visibility of structural steel, and the number of concealed areas that must be exposed for measurement.
What documentation do you need before starting a heritage lift installation? Architectural drawings, structural drawings, proposed finishes, and any heritage restrictions are essential. Where possible, we also review any previous refurbishment details to understand hidden steelwork.
Can hidden lifts be installed without damaging original features? Yes. Sesame lifts such as the Cavendish Platform Lift and Big Ben Electric Stairs are specifically engineered to preserve heritage architecture by integrating into existing staircases or flooring with minimal visual impact.
What if a beam or pit is out of tolerance? Adjustments such as shimming, gate-frame repositioning, extending post brackets, or revising pit steel layouts can often resolve discrepancies. Early discovery is the key to preventing delays.
How much variation is acceptable in a heritage lift pit? Typical acceptable variation is within ±5–10 mm depending on the component, though riser alignment and gate swing clearances may require tighter ranges.
Why is laser verification essential? Lasers identify real-world offsets that are impossible to detect from drawings alone. They often reveal 10–50 mm differences that must be accounted for in the model before installation.
Can temporary floor supports be installed without affecting heritage fabric? Yes. Temporary steel props or removable decking systems can be placed without impacting protected surfaces, and they are essential for safe load distribution during lift installation.
Call to Action To discuss your project or review your site drawings, book a meeting with one of our Project Managers. https://www.sesameaccess.com/book-a-meeting