Bellmanpark Limekiln

Background

Bellmanpark Lime Kilns were built in 1877 as part of Carter & Rowe’s limeworks. Like Heidelberg Materials UK Cement today, they were a significant local employer. 

Clitheroe Civic Society brought the condition of the lime kilns to the attention of Historic England and Heidelberg Materials UK Cement in early 2014. The Lime Kilns were added to the Heritage at Risk Register in October 2014.Volunteers from Clitheroe Civic Society have cleared vast amounts of vegetation from the kilns, allowing their condition to be assessed.

CCS’s Bellmanpark Limekilns Project Group (BLPG) has worked closely with Heilderberg Materials Management and co-ordinated a successful bid to Historic England which was confirmed in September 2018. Following a competitive tender exercise overseen by BLBG and Heidelberg Materials UK Cement, in February 2019 Conservation Engineers, Thomasson, were appointed by Heidelberg Materials UK Cement, and with the assistance of the Major Grant from Historic England (HE). This to undertake urgent investigations and Repair works to the limekilns which are now on HE’s Buildings at Risk Register. The Scope of the work envisaged as set out in HE’s Grant Award is:

Rebuilding of collapsed sections of the internal kiln walls,
Removal of corroding cast iron collars at the kiln bases,
Propping of deformed brickwork in vaulting,
Repair to loose brickwork in tunnels.

Record of Site Visit 29th October 2021 & Project Review

 
On 29th October a site visit was arranged by the Conservation Engineer and Lead Consultant, Jane Entwistle of Thomasons Consulting Engineers (TCE), to review progress of the works on site at Bellmanpark Limekilns. This structure was designated as a Scheduled Monument in September 2004 joining, Edisford Bridge and Clitheroe Castle as the only Scheduled Monuments within the Civil Parish of Clitheroe. It is also the only one in urgent need of repairs to prevent its continuing dilapidation and eventual loss to the Parish and the Borough. Before we present details of that visit the background to this project for those who may not be familiar with it are, briefly, as follows:

Over a period of four years Gordon Taylor and a team of dedicated volunteers, along with the support and assistance of Site Owners Heidelberg Materials, worked to remove the invasive vegetation from the external walls and top of the structure. This had almost completely covered the external faces of the ‘four pot’ kiln By 2016, when this work was complete (as indicated in our letterhead image above), it enabled Historic England’s forerunner - English Heritage - to resurvey the structure. The combined effects of the invasive and well rooted semi-mature trees and vegetation; water ingress from above - via the kilns’ unprotected top level; and from below via blocked drainage systems at lower and surrounding levels, resulted in the limekilns being put onto HE’s ‘Buildings at Risk Register’.

This was significant as it made the site eligible for grant aid. 2017, Clitheroe Civic Society (CCS) were invited to by Heidelberg Materials  to assist them with preparing and applying to Historic England for this financial aid. Arising from that invitation CCS’s Bellmanpark Limekilns Project Group (BLPG) was formed under the Chairmanship of Gordon Taylor, CCS Member, and former Bellman quarryman. That application was successful and in July 2018 HE awarded a 75% grant to site owners Heidelberg Materials to undertaken a £200k Urgent Repair Works project. That offer was accepted with Heidelberg Materials contributing the remaining 25% of the project costs.

BPLG continued to advise Heidelberg Materials on the appointment of a team of Conservation Accredited consultants. This eventually led to the appointment by Heidelberg Materials of TEC’s Jane Entwistle in 2019. Competitive tenders for the envisaged project were invited and the contract awarded to UK Restoration Services of Works of Burnley. Works commenced on Clitheroe’s ‘youngest’ scheduled monument in 2019. Adding to the complexity of this challenge were delays to the original programme arising from the effects of the 2020 Covid Lockdown alongside confirmation that bats were present on site. These conditions have combined to delay the intended completion of the initial programme of works due which had been due to take place in 2021. The implications of these delays are subject to ongoing discussions between HE, Thomasons and HMC. The following review of the October 2021 site and subsequent updates from the Lead Consultant and the Project Archaeologist, Nigel Neil, describes just where the project stands at the moment..

The invitation to BLPG members and associates to view the progress of the works on site was made in advance of works having to be suspended for this year. This to avoid any possible disturbance to visiting bats in accordance with the requirements of Wildlife and Countryside Act To date works have concentrated on the ‘South’ rail tunnel section of the original Three Pot Limekiln, being in much poorer condition than the parallel ‘North’ tunnel. Pot No.4 is deemed too unsafe to work alongside as much of this structure had collapsed internally prior to receiving Scheduled Monument status.

Site visit team from l-r Scott Dewhurst UKRS, Jane Entwistle TEC, BLPG Members & Associates – Gordon Taylor, Brian Jeffery, Peter del Strother, David Taylor, Andrew Collinson, and Nigel Neil Project Archaeologist.

Jane and Site Agent, Scott Dewhurst, gave us a detailed rundown of works that had either been completed or remain ‘work in progress’:

• Access into the site using the original entrance last used by James Carter and Sons in 1959, and formation of a secure works compound.

• Internal temporary support works to enable safe working practices’.

• Clearance of fallen brickwork masonry from within the accessible section of the South rail tunnel served by pots 1-3.

• Storage of existing red and fireclay brickwork for use on ‘like-for-like’ repair works.

• Clearance of silt and unusable debris prior to laying compacted stone hardcore, with steel fabric reinforcement, to overlay the original rail track level and form a stable, and reversable, working base.

• Repairs to South Tunnel and transverse arches alongside pots 1-3

• Temporary backfilling and shuttering to transverse access archways on the external south east wall to assist with its support and security pending further internal and external investigations and repairs.

• Levelling of the exposed limekilns top, removal of flora growth and the provision of a ‘soft capping’ (see more information on this below).

• Ongoing Archaeological recording of site conditions as these progress and, recovery, storage (where necessary) and eventual interpretation of all ‘in place’ or ‘recovered’ industrial archaeological artifacts.

Soft capping of the limekilns is something of an experiment on this scale in England and its use here in Clitheroe is now being monitored by Historic England. The technique for protecting the upper levels of historic masonry is one which promotes the growth of a deep grass and sedum capping using locally sourced turf and topsoil. This is turn acts like a retaining sponge, arresting water from migrating to lower levels until it eventually dries out. Though new on this scale in England, Historic Environment Scotland - and its forerunner Historic Scotland – have successfully promoted this technique since at least the turn of the Century.

Those interested to know more about it can do so by visiting the following site: https://issuu.com/hspubs/docs/soft_capping_in_scotland_vol_1/3 It has certainly been the subject of some lively debates and exchanges within BLPG, time alone now will determine just how successful this approach is! Initial views of the consultants are that water ingress from above has reduced. Drying out of the massive structure will still take some considerable time and, given the possibility of the pots remaining open - as has been the case with other conserved lime kilns elsewhere in England - this may have to be dealt with by other means. This issue is to be closely monitored by the Consultants and HE for some years to come.

In 2020, and coincidental to these works, Network Rail carried out repair and improvement works to the drainage ditch and culvert which runs to the north east and south west of the limekilns and crosses the Blackburn-Hellifield rail line twice. The dilapidated condition of this system was considered to be responsible, in part, for some of the frequent flooding of the ‘North’ and ‘South’ tunnels. Initial opinions are that this has reduced the water table around and within the kilns. The long term implications arising from this fortuitous coincidence remain to be seen and will be monitored by the Consultants.

This stage of the project is due for completion by w/e 10th December 2021 with the final task of removing the exterior invasive vegetation which has rapidly returned since its clearance in 2016. After this, and until April 2022, no one can now legally enter the kilns due to the presence of hibernating bats.

Just what the future holds for the limekilns after this date now remains to seen. BLPG are promoting a meeting of all interested parties including representatives from the Consultants, HMC., Historic England and Lancashire Wildlife Trust (who monitor the Biological Heritage Site which abuts the ‘north east ’ side of the Limekilns site). Topics for this meeting will include the following items - and no doubt others:

Date confirming recommencement of works and conclusion of the site, and desk, based Grant Aided Urgent Repair Works Project.

1 Extension of project work beyond that currently funded by Heilderberg Materials and the HE Grant.

2 The future approach to Pot No4

3 Future commitment of all existing interested parties to secure a lasting and meaningful future for this local and National Heritage Asset Site and Monument.

4 Wildlife accommodation during future works and on completion.

5 Opportunities for a future combined management approach to the Scheduled Monument Site and the adjacent Biological Heritage Site.

6 Review of current and future options and opportunities to secure the structure of this Scheduled Monument and promote its meaningful future as a local and national heritage asset.

7 Review of the practical assistance that BLPG can provide to Site Owners, Consultants and HE at this, and future, stages.

The visit to the site in October brought home to all just how complex the repair, consolidation and repair works are at this site. Jane Ellison confirmed that, in addition to covid, budget limitations and the presence of protected species on site, the most technically challenging aspect of the project has been ‘the instability of the internal brickwork which turned out to be in an even worse condition than had been anticipated’. It is hoped that these conditions, and possibly similar in the future, will not prevent an effective conclusion to this project. BLPG are committed to continue to do all it can to assist Site Owners HMC (commended for their continued support for this project), the Conservation Consultant Team and Historic England. Finally, BLPG will continue to inform CCS members on the progress of this project and its aims, which lie at the heart of the Society’s Constitution and Mission Statement to ‘To secure the preservation, protection, development and improvement of features of historic or public interest in the area’.

Steve Burke Dip.Arch. (Oxf’d)

Secretary

Bellmanpark Limekilns Project Group

7th December 2021

 Footnote: This site is closed to all members of the public at all times and no unauthorised visits should take place given the hazardous condition of the site and the need to respect and protect the nesting bats.

Progress report from Project Team Leader, Jane Entwistle,  December 2019

Work has been progressing on the lime kiln project but at this stage it has not been of a nature for which we have been able seek assistance from your group. We have undertaken a roped access inspection of the kiln top to check for whether there was any sign of the original top surface remained – this confirmed that whatever had been there had, as expected, been removed thus meaning that all the rain that falls onto the tops percolates down through the fill and then through the masonry structure; this is the prime cause of the deterioration of the vaulting. As a consequence I have been encouraging Historic England to consider some funding for a temporary measure that will help to significantly reduce the water ingress. After discussing various options with them I have proposed a paved top laid to a fall into a channel/gutter so that we can control where the water goes. This is not a permanent solution and as such is not designed to look permanent – the permanent solution will be a greater piece of work and we cannot expect funding for that at present.

Temporary support work has been undertaken in the south tunnel but none in the north tunnel as the condition there is so poor that installing it safely would be way outside the budget and would require the temporary works that will be required for the repair works. The work that will be undertaken in the south tunnel is relatively straightforward and safety precautions are achievable with relative ease. However, the north tunnel is much more complex due the amount of masonry fall that has already occurred. Our initial plan cannot be worked safely so much more extensive temporary protection will be necessary such that operatives are safe if more than just a few bricks fall; we have to be aware that the actual work of repairing the masonry could cause destabilisation especially where only a 4” skin of brick remains in place. A stone mason and a specialised (tunnelling) temporary works engineer have provided advice on safe means of access for the works. Due to the hibernating bats we are not allowed back into the building until March/April. In the meantime, an advert will be placed in the local paper in the next two weeks for expressions of interest in connection with the remedial works. Following receipt of the expressions of interest the project will go out for competitive tender in mid-January with a view to starting work in April – as soon as the bats have finished hibernating. I hope that this is of use for you to share with your colleagues in the Working Group”.

Kind regards

Jane Entwistle BSc (Hons) CEng FIStructE MICE

Since this report was submitted the intended programme of works on site , due to commence in March/April had to be suspended as a result of Coronavirus and event after the relaxation of the National ‘Lockdown’ the restrictions due to the presence of Bats prevents any site work commencing until Autumn 2020. WE are advised that this stand down time has been used to review various aspects of the project including the initial tenders received for urgent repair works, options for arresting water ingress into the top of the kilns and the implications of improvements to surrounding drainage systems immediately adjacent to the kilns undertaken by Network Rail on the Blackburn – Hellifield Line.

Jane Entwistle will be speaking to the Society and any interested visitors about the project at our May 3rd Meting 2021.

Initial research that was undertaken into the condition of the kilns

Historic England’s Civil and Structural Engineering Team visited in February 2015. Some areas of the kilns had already suffered from - or were at imminent risk of - localised collapse. Vertical cracks on most elevations and a widespread need for pointing was noted. Particular concern was noted for the vaults at the base of the kilns and tunnels. Propping was recommended to prevent further collapse. An inspection from above was recommended to inform the level of intervention necessary to stabilise the kilns. Historic England provided grant-aid for a full structural survey, produced by Anthony Curtin of Curtins in October 2015. The structural report outlines emergency repairs urgently necessary within 2 years. The findings corroborate the inspection report produced by Historic England’s Structural Engineer in February 2015, and that propping is a priority. Kiln 1 has collapsed. Brick facings have been lost from the passageways. There are open joints in the walls, and vegetation/roots, as well as tapering/tearing cracks. Concern was noted with saturation to the top of the kilns. Water would have been driven off while the kilns were in operation, but is now permeating the structure. The cost of urgent repairs was estimated at £79,500, excluding design fees, contractor preliminaries (15%), local authority charges and VAT.

Historic England’s Research team produced an Assessment of Significance in April 2016 to understand the rarity of Bellmanpark Lime Kilns in a national context. The research found that, as well as being nationally important as a Scheduled Monument, Bellmanpark Lime Kilns are a rare survival of kilns where quicklime was loaded directly into rail wagons in tunnels beneath the kilns.  Only 4 other examples are ever thought to have existed in England: only 2 of these survive.

Historic England’s Geospatial Imaging Team undertook laser scans of the kilns in December 2015 and June 2016 to understand on-going movement. The Monitoring Report identified an increase in size of cracks in the NE, SE and SW elevation of a few millimetres. Analysis of movement in the NW elevation was inconclusive due to the presence of vegetation, which affected comparison of all elevations to an extent. Historic England’s Senior Structural Engineer assessed that movement rate is not critical at this stage, given the size of the crack as a whole. However, he notes that this does not detract from the need to address urgent repairs.

A PhD student at University of Nottingham’s Geospatial Institute used Bellmanpark as a case study to test a new methodology for structural condition monitoring using terrestrial laser scanning and generalised procrustes analysis. The PhD is still in production.

Historic England’s Quantity Surveyor produced cost estimates following discussion with Anthony Curtin. The two agreed the measures outlined in the Quantity Surveyor’s Cost Estimates spreadsheet, but recommend that the final schedule should be determined following investigation by the Structural Engineer (or lead professional) appointed to carry out repairs. This relates in particular to whether temporary roofing or waterproofing of kiln tops is the preferred means of protecting the kilns.

The Quantity Surveyor noted that there are various combinations of repairs which could reduce or remove the necessity for some of the temporary works but would need a careful Value Engineering exercise. The QS’s estimated total for all urgent repairs including temporary roof is £187,889 excluding VAT

Next steps

Historic England North West has a strategic focus on tackling industrial heritage at risk. Emergency repairs to Bellmanpark Lime Kilns would fit in to this objective.

Historic England’s Repair Grants for Heritage at Risk scheme offers grants based on financial need demonstrated. All Historic England grants require a match funding contribution (which could include additional grant aid from other sources).

Historic England’s Repair Grants for Heritage at Risk are often in two-stages. Project development stages can cover further investigation, preparation of schedules of urgent works and clarification of costs; repair phases cover repair works. After the development phase, Historic England agrees with applicants the most appropriate schedule of works. Our grant offers usually comprise a firm offer for project development and an in-principle offer for repairs.

Grant procurement conditions would require Heilderberg Materials to obtain 3 quotes for appointment of a lead professional from conservation accredited structural engineers/architects or surveyors; Historic England could advise on possible conservation-accredited structural engineers/architects/surveyors.

Tamsin Cooke, Heritage at Risk Projects Officer at Historic England, could provide advice and support on preparing a grant application.

All Historic England grant applications are competitively judged

Longer term

Historic England can help with publicity/communications to highlight Heilderberg Materials’s contribution to community history and heritage through contributing to emergency repairs.

Heilderberg Materials expressed that they would in theory be happy to have open days to allow the public to see the kilns in a safe environment. These could happen up to 6 times a year. Public access is usually a requirement of Historic England Repair Grants.

The lime kilns could theoretically be transferred to a properly constituted Friends Group on a long lease, while Heilderberg Materials retained ownership. This would allow the Friends Group to apply for further grant aid.

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