CONTEXT 177 : SEPTEMBER 2023 39 WORKING WITH GLASS through windows. Even where they are apparently beyond viable repair, closer inspection can reveal opportunities for conservation. The extent of their unnecessary replacement, however, is still of concern. Servicing and repairs A draughty metal window may just need servicing in situ. This could involve easing and adjusting opening casements to ensure they fit snugly, tightening up loose ironmongery and dealing with defective or missing components. In some cases, broken or cracked glazing will need dealing with. Gaps in leaded windows may require resealing, for example, by renewing lime mortar around panel edges or regenerating old glazier’s cement where quarries are loose, using several applications of a 50:50 boiled linseed oil: turpentine mix, brushed on and left to be absorbed. A more extensive in situ overhaul may be required to remove excessive paint accumulation that has resulted in a poorly closing and draughty window due to pressure on components such as hinges. Care should be taken when rubbing down to avoid scratching the glass and to minimize the risk from hazardous dust. Small areas of paint may be removed with chemical strippers. Bear in mind that wholesale cleaning will destroy all remnants of earlier, underlying paint schemes. Aim instead to leave some evidence behind. Distorted wrought-iron or mild steel members can often be readily eased back to square using a wrench after servicing to ensure proper operation first. Glass only needs removing beforehand where frames are distorted significantly, when it may be necessary to strap the deflected section to a stiff wooden framework using ratchet straps, which are tightened gradually over a number of days. Infrared putty softening lamps are unsuitable with metal windows. Facing putty will require carefully scraping away, and glass eased gently from bedding putty with a sharp knife and perhaps a thin lubricating oil. While light rust can be cleaned off manually or with power tools, and holes filled, severely corroded windows frequently require treatment in a workshop using acid pickling, air abrasives or, in the case of wrought-iron, flame cleaning. Cleaning may reveal heavily corroded sections needing repair. Wrought-iron components can be repaired by cutting out defective lengths and welding in new pieces in the same material, as can steel members where the profiles are still available. Cast-iron is most easily repaired by cold stitching. Specialist iron foundries can take moulds from cleaned originals and recast components. Treat bare ungalvanized metal with zinc phosphate primer before repainting. Proprietary draughtproofing systems Servicing and repairs will cut down many draughts, but metal windows can often benefit further from the application (or reapplication) of a silicone foam rubber sealant to fill gaps between sealing faces. While excessive draughts are undesirable, draughtproofing should not overly restrict ventilation. Ventilation helps prevent dampness in buildings, especially in kitchens and bathrooms. Older houses must breathe, so require more ventilation to remove structural moisture from their breathing fabric than their modern equivalents. Proper ventilation also maintains indoor air quality, and is important in rooms with open fires and flues. Clues can assist with pinpointing the sources of draughts where these are not obvious. For example, air movement might be felt by running a hand along casement perimeters. Draughty windows can whistle and rattle, and curtains A wrought-iron window set in a timber mullioned frame in Stogursey, Somerset, with a casement stay and an unusual casement fastener (Photos: Douglas Kent)
RkJQdWJsaXNoZXIy MjgyMjA=