Resources

September 2011 Windows

Welcome to September's email bulletin. This month our topic is windows. If you have a subject that you would like us to cover in a future bulletin let us know by emailing the team at info@spabfim.org.uk.

Things to think about...

Damaged leaded windowLeaded windows: Although leaded windows are fairly robust it is advisable to check their condition on a regular basis, using binoculars if they are high up.  Look for broken or cracked panes of glass and inspect the cames (the H shaped strips of lead that make up the lead matrix) and wire ties for signs of damage.  If the panels appear to be buckled or deformed this might indicate that the lead matrix has deteriorated.  Report any deformed windows to your professional adviser.

The condition of the ferramenta (the structural metalwork that supports the leaded panels) is important too.  Rusting metal will expand and can cause the surrounding stonework to crack and split, so it is important that any metalwork is kept in good condition.  Most metalwork, including cast iron and mild steel, needs the protection of a regular coat of paint, especially if the building is located in a coastal environment.  Ferramenta can also be tipped with stainless steel or phosphor bronze to protect the section embedded in the wall from rusting.

Lead matrix

Timber windows: Sometimes timber casements or sliding sash windows may ‘stick' and be difficult to open.  This is usually caused by a build up of paint layers over the years and can be easily remedied. 

Timber windowA skilled carpenter or joiner can gradually work the panel free.  Excess paint layers should then be carefully sanded away and the whole window repainted.  Damp weather will also cause timber windows to expand and the panels to stick.  This can be remedied by carefully sanding the panel frames and rubbing them with candle wax.  Sash cords in sliding sash windows will need to be replaced with new waxed-cotton sash cords from time to time.  As this requires the window to be dismantled, you will need to seek specialist help.

Metal windows: Metal windows were traditionally made from one of three materials: wrought iron, cast iron or mild steel, although examples of bronze and copper frames do exist.  If they are properly maintained, metal windows can last for centuries but corrosion may occur if protective coatings are neglected. 

Metal windowsUngalvanised steel windows (generally pre-dating 1950) are the most susceptible to rusting under these circumstances, though wrought and cast iron can also be affected.  Corrosion leads to the loss of original material and staining on adjacent surfaces. 

It may also cause glass to crack and masonry to split at fixing points (‘rust jacking') as the rust occupies up to seven times the volume of unoxidised metal.

Other potential problems include the fracturing of cast iron because of impact or casting flaws and the distortion of wrought iron or mild steel following forcible closure of casements where there is excessive paint build-up.  As a rule, metal window frames will need regular painting every three to five years to prolong their lifespan.

Well maintained metalwork

Things to do...

  • Make sure that opening panels in leaded lights are operable so that the building can be ventilated on dry days during the summer months.
  • Clear away any dirt from condensation drainage channels and holes at the base of leaded windows.
  • Check whether timber and metal windows can be opened easily - seek advice if they are found to ‘stick'.
  • Consider whether window panels and frames require repainting - seek advice with regard to choosing an appropriate type of paint.

Further information

Need more help?

If you have any questions about maintenance or repair issues contact our Technical Helpline for advice and guidance. This service is normally available on Fridays between 9.30am and 3.30pm on 0207 456 0916.  Alternatively, you can email your questions to advice@spabfim.org.uk. Copies of the SPAB's range of Technical Pamphlets and Information Sheets are available to purchase from our online bookshop.

Parish Studies Today - A Call for Material

For its tenth anniversary in May 2012, the Warwick Network for Parish Research is casting its net wide in its search for topics and presenters. If you've been involved in any local history initiative in your parish (academic or practical), you might like to get involved.  Further details are available on their website.

Sara Crofts

Faith in Maintenance Project Director

Stave off decay by daily care ~ William Morris 1877