Church preservation work

Because of worrisome structural disorders, a preservation plan is being considered in the parish church. As a safety precaution, the church is temporarily closed to worship and visits.

Our church’s building presents serious damages to its structure and requires significant masonry, framework, carpentry and roofing work. Serious deterioration may endanger certain parts of the building, and for safety reasons, it is no longer accessible to the public.

The decorations are threatened with disappearance, by wear and tear, water infiltration and xylophagous insects.

Because of the advanced state of deterioration of the building, the bell may very well be unable to be used as its swing weakening the structure which supports it.

We invite you to read the report below, established by the architect specialized in heritage conservation and the proposals made to avoid the worst. The amounts involved are considerable.

The state of play

Several structural elements of the church present an alarming vulnerability:

The stresses on the frames are excessive with regard to the resistance of the materials at the nave and the bell tower level.
The vault of the nave is highly unstable.
The structure of the bell tower presents disturbing disorders.

The Diagnosis

The purpose of this study prior to the restoration work of the Notre-Dame church is to carry out an overall diagnosis of the building to determine the major maintenance and restoration work of the main constituents of the enclosed area and the effects interior. These works will be classified as per their degree of urgency according to an economic and functional study – not taking into account, at this stage of the study, the financing capacities of the municipality.

The study, commissioned by the town of Ménerval, presents:
– a presentation of the building it in its current context and history,
– a diagnosis on a map presenting the pathologies identified also in the form of a non-exhaustive photographic report illustrating the inventory of materials and pathologies identified during our visits,
– a restoration project stipulating the restoration part and the summary description of the work by building,
– a rough estimate of the work and costs addressing financial issues and phasing of work as per their order of priority.

This study describes the restoration project proposed by the contractor and the work program by listing the different subtrades and a rough estimate of the proposed interventions.

A series of assumptions have been made to meet the needs to preserve the building’s walls and have defined a provisional envelope to program the works in the years to come.

COVERING

STATE OF PLAY:

The covers of the porch, North transept, the choir and the eastern slopes of the south transept are made of slate. The staircase turret, the western slope of the southern transept, the southern slope of the nave as well as the bell tower are made of slate laid with nails. The north side of the nave is in flat country tiles.

DISORDERS OBSERVED:

The cover of the tower seems in good condition and could be even left untouched for the years to come.
The southern slope of the slate nave presents some sections, notably to the right of the western bank. The entire southern slope is out of use and leaky, the slates are mossy, covered with lichens and there are significant gaps.
All waterproofing flashings are out of order.
The north slope of the nave is in flat country tiles, as were all the roofs of the church before the work of 1876.
The slate roofs of the North transept and of the turret are in a state of conservation which would require a simple revision while the cover of the South transept arm is in used condition and will need to be replaced.
The replacement of the tile roofing with slate for the southern slope was carried out in 1941.

CONCLUSION AND PROPOSED INTERVENTION:

Slate should be considered for the partial restoration of the hedges.
Concerning the covering of the nave, it was decided to restore it using slate with nails, but however a variant can be considered to restore the covers in flat tile. (More demanding given the high volume, exposure to winds and the maintenance requirements).

All waterproofing flashings between the roofs and masonry elevations will be redone to ensure the building is waterproof. Tile roofing, if this was considered, could be reinforced with the installation of under roofs.

ROOF INFILTRATIONS

STATE OF PLAY:

The visible part of the old frame corresponds to the arrangements painted in gray: crown post
and truss beam, line of two corbelled wall plates. It should be noted that a first wall plate, placed on the edges and in the continuity of the masonry interior wall, carries the truss base. The hoops of the wooden vault, later covered with plaster, and the construction arrangements of the vault are perfectly visible from the attic on the lower north side. The vault of the nave was completely redone in 1855, but traces of an old douvain vault are still visible on the west bay.

The frame with trusses and collar beam may no longer be independent of the structure of the vault after its complete repair.

The external wall plates could not be observed, nothing suggests that there could be a disassembly at the level of the truss feet, no thrust on the walls or significant deformation at the level of the cover slopes.

DISORDERS OBSERVED:

The frame and the vault of the nave are degraded due to the successive waterways infiltrations, with localized attacks of large woodworms on the wettest parts, accompanied by a development of fungi which we have confirmed by laboratory analyses that ‘it was not dry rot.

The low interior wall plates are severely degraded and have lost their mechanical capacity, the blistering observed locally on the side confirms the necessity to replace them.

CONCLUSION AND PROPOSED INTERVENTION:

After removing the cover, a precise sanitary condition of the frame condition will be carried out. However, a partial replacement of the interior and exterior wall plates and the examination of all the assemblies is to be expected.

The most damaged woods will be purged and will undergo a spray/injection treatment in the case of a large woodworm infestation.

In all cases, the springs, crown posts and truss beams of the primary framework will be preserved and restored.

The wooden structure of the vault will also be treated and restored to allow the implementation of either one of the following alternatives: restore the arrangements in place or restore a douvain vault placed in a dimple frame in the grooving provided for this purpose on the joint covers.

Note: a dendrochronology study could be carried out and have a historical interest in the dating of the structures of the vaults of the choir and the nave.

ROOF INFILTRATIONS

STATE OF PLAY:

The visible part of the old frame corresponds to the arrangements painted in gray: crown post
and truss beam, line of two corbelled wall plates. It should be noted that a first wall plate, placed on the edges and in the continuity of the masonry interior wall, carries the truss base. The hoops of the wooden vault, later covered with plaster, and the construction arrangements of the vault are perfectly visible from the attic on the lower north side. The vault of the nave was completely redone in 1855, but traces of an old douvain vault are still visible on the west bay.

The frame with trusses and collar beam may no longer be independent of the structure of the vault after its complete repair.

The external wall plates could not be observed, nothing suggests that there could be a disassembly at the level of the truss feet, no thrust on the walls or significant deformation at the level of the cover slopes.

DISORDERS OBSERVED:

The frame and the vault of the nave are degraded due to the successive waterways infiltrations, with localized attacks of large woodworms on the wettest parts, accompanied by a development of fungi which we have confirmed by laboratory analyses that ‘it was not dry rot.

The low interior wall plates are severely degraded and have lost their mechanical capacity, the blistering observed locally on the side confirms the necessity to replace them.

CONCLUSION AND PROPOSED INTERVENTION:

After removing the cover, a precise sanitary condition of the frame condition will be carried out. However, a partial replacement of the interior and exterior wall plates and the examination of all the assemblies is to be expected.

The most damaged woods will be purged and will undergo a spray/injection treatment in the case of a large woodworm infestation.

In all cases, the springs, crown posts and truss beams of the primary framework will be preserved and restored.

The wooden structure of the vault will also be treated and restored to allow the implementation of either one of the following alternatives: restore the arrangements in place or restore a douvain vault placed in a dimple frame in the grooving provided for this purpose on the joint covers.

Note: a dendrochronology study could be carried out and have a historical interest in the dating of the structures of the vaults of the choir and the nave.

VAULTING AND FRAMEWORK

STATE OF PLAY:

The frame comprising the primary frame in oak with truss beam and carved crown posts, a succession of carved corbelled wall plates could date back, for certain rooms, to the beginning of the 16th century. However, the observations made on the spot and the information gathered on the various work campaigns suggest that many pieces are no longer original (dendrochronology would shed light on these doubts).
In addition, we do not have enough information on this point, but it seems that in 1902, the vault of the choir was still polychrome.
A brief glimpse of the roof frame from the bell tower, allowed us to confirm the arrangements of a truss frame whose vault structure is linked. The hoops are assembled in the ridge of the vault and probably in the rafters. The douvains are assembled in “langues de vipère” with joint covers.

DISORDERS OBSERVED:

Except for a few scattered elements, the vault is in good condition.

As far as is visible, the framework truss beam and crown post are also in good condition, the stability of wall plates and the pockets of the ends of the carved enterties remain uncertain. This set constituting the base of the vault and the framework has long been wet, evidenced by the traces of significant development of carpophores (or oval traces) on the surface.
In addition, the weakness of the “decorative boards” which bend under the weight of the roofing rubble could cause the entire structure to fall.
Laboratory analyses carried out on samples of dry wood and carpophore indicate that it is not dry rot. However, the consistency of the wood, especially the lower wall plates, has lost all mechanical strength, which explains the blistering associated with the section crushing.

CONCLUSION AND PROPOSED INTERVENTION:

Structurally damaged wood will be replaced as underpinning. The decorations will be preserved in their entirety and reassembled by gluing on new wood.
A revision could be considered on the vault but no surface treatment by spraying is planned at this stage of the study.
The stripping of the sewer will allow a complete examination of the wall plates; we will only treat the bottom of the slope to remove water infiltration and replace the gutters. The rubble at the level of the sculpted wall pates will be removed from the outside.
A solvent-borne fungicide treatment could be considered. The aqueous phase is to be avoided because it causes irreversible aesthetic disorders on the woods by dripping and migration of tannin.

THE TURRET

STATE OF PLAY:

The frame of the turret consists of a half groove, a short crown post and a series of rafters. The whole frame is consistent except for some late repairs with cleats and the double crown post (or additional crutch placed on the ground) whose usefulness is not obvious.

The turret is moored to the north wall of the bell tower by a mixed tie rod in oak and metal plate, the whole structure bolted to the passage of the north gable of the transept. These well-preserved arrangements are quite old and now stable. The mooring beam crosses the floor of the transept roof. This floor has probably been raised and does not match the ceiling of the lower level.

DISORDERS OBSERVED:

The turret frame is in good condition and will be preserved.
The framework of the North transept has been altered several times, and cannot be kept as is, especially as a tarmac under-roof has been installed on the western slope and this arrangement presents a containment that could result in the ‘aggravation of existing disorders.
Towards the south, the purlin was fixed by a fitting hanging from a
larger section rafter acting as a crossbow. Another rafter in the truss beam abuts the “false truss”, where the base seems to have disappeared and where the block is anchored to the level by a fitting which consequently prevent the crossbow foot from slipping.
The rafters, of different sizes and sections, re-used or newer, are in poor condition. The assemblies with the blocks and the rests on the wall plates are not guaranteed stability, sometimes tinkered with every other row. The wall plates, cluttered with rubble, are altered, clearances will be necessary in order to make a complete sanitary examination.
In addition to this, you need to know more about it.

CONCLUSION AND PROPOSAL FOR INTERVENTION:

The turret frame will be checked, treated with insecticide fungicide and kept as it is.
The frame of the transept arm will be completely taken over, old wood in good condition will be kept as much as possible. Depending on existing arrangements, truss will be restored or returned.
The leveling will be cleaned and an access to the bottom of the rampant of the nave could be arranged (subject to feasibility).