C O N T E X T 1 3 4 : M A Y 2 0 1 4 37 Darren McLean is the owner of Timber and Lime Conservation. often expand.The exception is where dowels or wedges have failed, allowing the stile to ease from the rail. Before planing anything at all, liberally apply beeswax to the frame or stile: it can work wonders. Avoid using a hammer and chisel when removing window components such as parting and staff beads. Break the paint bond between components with a sharp knife.Then use two putty knives side-by-side, inserted between components to pry them apart. This is more efficient and far less damaging to the fabric of the window than hammer and chisel. A duckbill welder’s clamp can also be used to obtain purchase on beading when an element of force is required for its removal. Something frequently overlooked is the cleaning of debris from the window frame void or pockets. When originally installed, a bed of haired lime mortar bridged between the window frame and the masonry. Over time, due to the movement of the window and weights, this mortar can fall and collect in the void. When servicing windows this mass must be removed. The Victorians used tightly rolled, wetted newspaper as a form of caulking between haired mortar and sand mastic. Unfortunately this has not been well understood, and it evolved into the wholesale stuffing of newspaper between wall and frame. That practice can interfere with the movement of the sash weight and again harbour dampness. Thorough preparation and priming prior to painting is vital. Where paint has been missing for some time, the wood’s softer summer growth may have weathered. This will not affect the overall strength of the wood if caught early enough. Make good with a preservative, a wood filler, primer and quality paint. A 50/50 blend of boiled linseed oil and white spirit makes a simple yet effective preservative. End grain is far more absorbent than side grain and should receive additional coats to ensure adequate protection. Where existing glass is to be replaced, any increase in weight will need to be counterbalanced with a corresponding increase to the sash weights. This may mean the sashes are restricted in travel, due to the longer weights: wider weights may not fit into the space available.Where existing glass is to be retained, putty can be carefully removed and reinstated once all other repairs are complete. Use chisels with great care. Another method is to use an oscillating saw flat against the glass to cut out the old putty. Tape a hard plastic sheet to the pane to prevent the flat of the blade scratching the glass. The steam from a wall paper stripper can soften putty for easy removal: a simple cover creates a letterbox slot, allowing the steam to be concentrated on the putty. Care must be taken not to heat the glass so much that it cracks. Beware of lead paint. If paint is old, assume that lead is present and take the appropriate precautions to protect yourself and the environment. Timber and Lime Conservation Ltd Block 2 Unit 2, Tollcross Industrial Estate, 3 Causewayside Crescent, Glasgow G32 8LJ 0141 249 0191 www.timberandlime.com TLC provide craft services to building professionals, contractors, in particular those new to conservation and building owners alike. We take pride in providing the following services in a high quality, conscientious and timely manner: • Joinery • Lime mortars • Mosaic, timber and stone floors • Roman and early cements • Original materials identification • Appropriate materials selection • Materials sourcing TLC owner, Darren McLean is experienced in heritage training and advises on: • Historic materials, applications and original techniques • CPD/Education days for students of all levels • Public events, presentations and talks • Personalised training for building professionals • One to one instruction Visit woodwindowalliance.com Unmistakable. Wood windows as authentic as they are efficient. Authentic period windows with modern performance. Bespoke | Durable | Double or single glazed | Nationwide installation
RkJQdWJsaXNoZXIy MjgyMjA=