Technical note: Doors

Doors

Of all building elements, windows, doors, their fittings and embellishments can often tell more of the history of a building than any other

Early boarded doors were made from very wide planks simply jointed and held together by broad horizontal rails on the inner face. As time went on the boards became narrower and the jointing involved. To the ledges were added diagonal braces and latterly a complete jointed frame. Most early hinges are simple forged straps fixed with wrought nails; in the 19th century the 'T' hinge fixed with screws takes its place. Early fastenings are timber draw bars or lifting latches which in the 19th century are replaced by iron thumb latches and later still by mass produced steel latches of a similar pattern. 

Panelled doors in the 17th and early 18th century come in a wide variety of panel formations; architraves are broad and often heavily moulded. By the end of the 1 8th century the 6-panelled door was the popular form with a careful gradation of size, proportion, and detail. Separately applied ‘bolection’ mouldings (see note 41) had been replaced in time by carefully worked mouldings on the arises of the frame rails and muntins. Scholarly copies of classical details were assembled to form the encasements, often linked with a decorative fanlights and side lights. 

Porches are rare until well into the 19th century when these features were often added to older buildings. These were not always added with the sympathy that such an important feature deserves. As the 19th century proceeded 4-panelled doors became more popular, bolection mouldings came again into use and the pattern of architraves and encasements were courser and no longer followed recorded antique forms. 

Fittings developed from face fitted 'H' or 'L' shaped hinges of the forge, to cast leaf hinges, concealed in the interface between door and frame. Early locks are all rim fittings mostly operated by iron or brass drop ring handles; lock facings and finger plates are sometimes highly decorative. For external doors, locks with a double thrown action were often used, backed up by simple but sturdy draw bars. 

By 1800, knob furniture was more common, often made of porcelain and highly decorative. Later mortice locks replaced the rim patterns and lever, or simple undecorated knob furniture was used. Generally external doors did not have handles as part of the lock or latch but were drawn to by means of a heavy knob centrally placed or a ring that may also serve as a knocker. 

Like windows, external doors were painted until in the late 19th century imported hardwoods became cheap enough for some people to use them for entrance doors as well as internal doors to the principal rooms. 

Faults and repair 

The timber used for joinery in the 18th and 19th century was generally carefully selected and the joints were tightly formed, the tenon being drawn by a peg into the mortice against the shoulders of wedges. As an added precaution the joint was fitted before assembly with hot animal glue or white lead thus making it waterproof. Consequently, provided the unit has not been forced or otherwise abused while repainting, and glazing putty, etc, has been regularly attended to, faults should be few. 

However, the sad fact is that many of these carefully constructed units have not been cared for as they deserve. Sheer neglect coupled with misuse are the major destroyers of historic joinery. Windows commonly suffer from broken cords, seized pulleys, and distorted catches. During reglazing instead of cleaning out the reveals, successive levels of perished putty had often been built up one upon another; condensation has entered the timber through the perished putty so that finally there is nothing to hold the glass in place. These units become draughty and are no longer weatherproof; they are then condemned wholesale without serious regard for the very real chance of repair. 

Doors similarly suffer from neglect of painting, and the severe wear of hinges and thresholds. Often these faults are not analysed, and the decision is made to replace the entire unit with a needle loss of historical material. 

Structural movement, the failure of lintels or other local failures such as the rusting and consequent swelling of iron cramps in adjacent stonework are all serious threats to the joinery itself. Distortion of the opening leads the masonry and joinery to part company; water enters the gap and decay follows. More movement may strain open (wrack) the joinery joints followed again by entry of rain or condensation and consequently the decay of the timber around the joint. 

Insect attack is rare unless beetle has infected the timber before it was converted for joinery. Regular checks for all windows and doors should be made in advance of each programme for redecoration and the necessary repairs completed before redecoration is implemented.

Note - with higher heating standards and increased heating bills, owners are becoming more aware of heat loss around windows and doors. Properly fitting units will go a long way towards reducing heat loss. The setting of ironmongery stops beads, etc, will greatly improve performance, and further increased efficiency can he obtained by fitting draft proofing strips. Most of the better draught proofing strips are best fitted when the units are dismantled. This modification can he made without any change in the appearance of the units themselves. Remember to consider ventilation when fitting draught proofing. Otherwise, condensation may become a problem. A passive ventilation system, vents trough the sash box or ensuring a flue remains open may become necessary. 

Double glazing is another means of heat conservation. Many older buildings have relatively small, glazed areas in comparison with the overall area of wall and the savings to be obtained may well not be an economic proposition. English Heritage have calculated that it will take 60 years on average to repay the cost of installing double glazing in terms of savings on energy (see Framing Opinions leaflets). It is much more energy efficient to increase insulation elsewhere. If improvement of the performance of windows is considered necessary, then secondary glazing is a more acceptable solution. This gives much better thermal and sound insulation characteristics and does not damage the historic window. Secondary glazing bars should follow the pattern of the existing windows. Double glazing will not be permitted by Environment and Heritage Service for Georgian Paned Windows. This is because the glazing bars will have to be thickened to accommodate the units altering their appearance. Note: Double glazing is an alteration which requires listed building consent. 

Notes on the preparation of contract specifications 

• identify units for repair and replacement. 
• describe the necessary repairs for each unit and the design - mouldings, panels, shape of glazing bars, etc, to be used for replacement. 
• describe the materials to be used - type of timber, type of glass, ironmongery, etc. 
• give instructions for dismantling, stripping off old paint and putty, storage and care of material for reuse. 
• name any preservative treatment of timber and the priming for all surfaces before assembly or glazing. 

Further reading 

• Framing Opinions, 1 Draught Proofing, English Heritage, London 1994 ref XH20020
• Framing Opinions, 2 Door and Window Furniture, English Heritage, London 1994 ref XH20021 
• Framing Opinions, 7 Energy Savings English Heritage, London 1994 ref XH20026 
• Nessa Roche, The Legacy of Light, A history of Irish Windows, Wordwell Ltd , Wicklow, 1999. 
• Doors Timber Panelled Doors and Fire, English Heritage Technical Guidance Note, London, 1997. 
• The Georgian Group Guides No3 Georgian Doors, London,1990. 
• Period Houses, A Conservation Guidance Manual. Dublin Civic Trust, 2001. Chapter16 Doors and Doorcases.