THE CONSERVATION OF LISTED BUILDINGS AND OTHER OLDER BUILDINGS
INFORMATION FOR OWNERS
These notes are not intended as an exhaustive guide. They are, however, intended to assist the owner or occupier of a Listed Building to understand aspects of Conservation more closely. They are also intended to provide a pointer to the standards he or she should be looking for when work is carried out on a building. The notes may also be relevant to other buildings that have not been included on the statutory list as providing a reasonable standard of repair or restoration.
Chimneys are almost always part of the character of older buildings, and their retention is very desirable to retain this character and also to maintain the historic skyline. Since the introduction of the Clean Air Act their use has diminished, however. If you have a disused chimney, you may wish to consider the following guidelines:
(a) Ensure that it has been swept.
(b) If the chimney is sealed off make sure it is ventilated top and bottom.
(c) Retain the original fire surround and hearth.
(d) Make sure that the flashings and soakers at the roof junction are watertight.
(e) Try to retain the original chimney pots.
If any problem is encountered, or suspected, please seek advice at an early opportunity. It may be possible to identify a means of providing a 'holding' measure until it is possible to effect a permanent solution. Structural problems are many and diverse and could include walls needing underpinning, separation of skins to a cavity brick wall, dry rot, beetle attack, rising or penetrating damp or condensation.
Most structural defects relating to Listed Buildings can be satisfactorily addressed or corrected, but obviously the problem will increase over time if they are allowed to persist, and this may be taken into account when applications for grant assistance are considered.
'A stitch in time' is the maxim and problems should not be allowed to accumulate by inaction. Owners are encouraged to talk to the Conservation Officer concerning structural defects and where practicable to spread the cost of the remedial work.
The Conservation Officer will be able to advise on additional information on technical and specialist services.
Roofs and Gutters
In almost all cases the original roof covering is the one that the roof structure was intended to carry and the one that looks right on the building.
Where the original roof covering has been replaced, owners are encouraged to consider replacement of modern roof tiles with slate, if this was the original material. Slate suitably fixed will last three times as long as concrete tiles. Fixings for slates should be nonferrous (63.3 6.1) copper, zinc, tin type or stainless steel. The extent of any repairs to roof timbers should be agreed with the Conservation Officer before work begins.
Gutters and downpipes should also be maintained in good condition and cleared regularly to avoid problems associated with blocked or leaking gullies and downpipes. Replacements should match the original. When painting make certain the joints are watertight and paint the inside surface of cast iron gutters with bituminous paint. Where gutters have been changed to modern plastics, encouragement will be given to their reinstatement in cast iron, where this was the original material.
Doors and their surrounds are an indication of the importance, real or imagined, of the past owners of a property. Care should be taken to preserve original and later detailing and furniture. The general rule should be to repair rather than replace when considering maintenance. Similar systems of draftproofing described in respect of windows may be appropriate for external doors.
Brick and Brickwork
The majority of bricks used on historic buildings within the Borough of Gosport have been made locally and these are generally now difficult to match accurately. It is therefore important to keep the original bricks in good condition, making certain that when repointing is required a suitable mix of appropriate materials is used and that approved techniques are employed when carrying out the work.
The pointing to brickwork has a great impact on the character and finished appearance. Mortars on buildings old enough to be 'listed' are normally lime based and any new pointing should be in the same material in a mix agreed with the Conservation Officer before work begins. A suitable mix will take into account colour, texture and exposure. An unsuitable mix, especially cements applied over lime materials may result in frost damage causing 'spalling' of the face of the bricks. Pointing should be flush, held just behind the arris of the brick and lightly brushed after the initial set. Struck or strap pointing, which allows mortar to invade the face of the brick, is not suitable as it will result in a change of character to the brickwork.
Cleaning of brickwork is a very specialised operation and should only be undertaken when deemed essential and then only by an approved specialist firm.
Window type and detailing is in most cases the most important element in relation to the character of a building. The preservation of windows in original condition is therefore a key element in retaining a building's character.
If a window shows signs of rot in the sill, the whole window need not necessarily be discarded, as the affected area can be cut out and replaced.
Original glass should, if possible, be retained in older windows because crown or cylinder glass has a distinct character of its own and replacement is difficult.
In the case of sash windows modern glass can create problems in balancing the sashes due to its extra weight. Crown glass is now available again, while cylinder glass may also be obtained from sources on the Continent.
In the case of sash windows sash chords should be checked regularly and replaced as necessary, or if chains are used, these should be oiled periodically. Sash windows are designed so that some of the beads can be replaced when worn. The parting beads should only be a push fit into the boxframe to allow them to be easily replaced, an over sized bead may be appropriate if wear to the sash is excessive, so reducing rattle.
Double glazing will not normally be suitable for replacement to historic windows. If there is a heat loss or draft problem there are specialist firms that may provide the cure, or as a last resort a suitably designed system of secondary glazing should be considered. Listed Building consent should be sought before installing secondary glazing.
Many of the buildings constructed up to the first half of the 19th Century have rendered exteriors of lime based or Roman cement renders applied in three coats, usually lined to simulate ashlar blocks. In the case of failure of the render it is important to:
- cut back to ashlar lines to help hide the patching,
- use a lime based mix of similar strength and texture.
Historically these renders were finished in lime wash usually tented to simulate Bath stone. Lime wash is still available, and being a natural material is compatible with the render and is very durable, if applied correctly. Renders are a complicated material to apply, getting the proportions right and using the appropriate grits and sands are the key to successful repair.
Stone in the Gosport area may have come from one of several sources, of these stone from the Isle of Wight, Portland and Purbeck is most commonly encountered. If replacement is necessary and the original source is no longer in production there are still sufficient English quarries operating to be able to find a suitable replacement. In difficult cases there are also continental quarries that could be considered as a source of replacement.
The pointing of stonework is in principle the same as for brickwork. The cleaning of stone work is again a very specialist operation to be carried out only by an approved contractor.