In unframed masonry walling any large opening will introduce a point of weakness meaning that particular attention must be paid to keeping out rain and draughts.
The weight of the structure above will need to be carried across each opening to transfer it back to the walls. Arched openings achieve this neatly by specially cut or moulded wedge-shaped stones or bricks (voussoirs) but rectangular openings require extra help in the form of beams or lintels. In traditional construction two of these are often combined across each door or window. An outer length of masonry built into the front thickness of the wall is reinforced by a second inner timber beam known, not always accurately, as a safe lintel. Like any timber product it will be vulnerable to unseen decay, especially since it will be concealed externally by its companion lintel and will probably also be hidden inside by plaster or another wall finish. Failing safe lintels should therefore be replaced in concrete or steel rather than being repaired or refitted in wood. Some stone lintels have an upper relieving arch of thin voussoirs to take the weight off their centres. These features can be surrounded by small stone pinnings in clay mortar, designed to absorb any movement and thus protecting the lintel from cracking. Such areas should not be filled with cement or lime but be pointed again with clay, although lime might be used for surface pointing to maintain a consistent appearance overall.
CHURCH WINDOWS come in a great variety of shapes and forms. Made usually of wood, moulded stonework or sometimes metal they range from the simplest utilitarian types to stupendous examples of the skills of the mason and the stained glass artist. Standards of construction also vary greatly.
Durable wooden frames can last for many generations with only minor repair if any. They may not be so reliable in cheaper construction and particularly not in churches built or repaired in the aftermath of World War 2 when high quality, well-seasoned timber was hard to obtain.
Such windows may well need complete replacement when time shows up their defects but be wary if advised that older or better-specified examples should be discarded. A good joiner will be able to repair many a window frame that is partly rotten at less cost than buying and fitting a new one which will very likely have to be purpose-made. Their sills tend to be vulnerable and may need painting more often than the rest of the frame. Reject new hardwood sills containing knots. These can shrink and allow water penetration. Make sure that any saddle bars fit safely into their reveals.
Metal Frames can be stressed, for instance, by warping and twisting caused by temperature variations over time. Repair may be possible but windows of the same design may still be made by firms such as Crittalls if needing replacement. Expect modern replacement designs to offer better heat and sound insulation. Opening lights can be draught proofed if necessary.
For every type of window it is important to keep an eye on all mastic and putty sealing and to maintain it intact against moisture penetration.
As you would at home, ensure that excessive repainting of wooden or metal frames has not sealed up opening lights, so preventing ventilation or proper closure.
And think carefully before replacing your windows in uPVC plastic which is likely to spoil the character of all but the most ordinary church building. Unlike timber it has the serious drawback of being difficult or impossible to repair. It also includes high embodied energy and has no such assurance of long life.
External DOORS should undergo regular redecoration and other necessary overhaul. Watch for rust and other difficulty with iron fittings, hinges and locks as part of your regular inspection. A good joiner will be able to piece in new timber to remedy damage to wooden doors.