Conservation Officer

The question of whether to repair or replace timber windows and doors on a listed property or those located in a Conservation Area, can be a contentious issue. By the very nature of the property’s heritage, it can be a difficult task trying to balance the preservation of its historic significance and the needs of those who reside in it.

Recognising this, a group of members within the Wood Window Alliance have invested in a specialist range of heritage designs to provide sympathetic replacement of timber windows and doors in listed properties.


Replication of original designs

When replacement is appropriate, either due to the condition of the original window/door or previous inappropriate replacement, our members can customise heritage designs to replicate originals. Whether a client is looking to replicate Georgian, Regency, Victorian or Edwardian designs, our members can provide authentic mouldings, specialist glazing and period hardware. Some members are able to incorporate existing glazing and/or hardware at no detriment to the performance of the new window or door.

Typically the authentic mouldings comprise of the following:

  •  Lamb’s Tongue
  •  Gothic
  •  Ovolo
  •  Bevelled

For sash windows, a number of sash horn designs can be incorporated into the top or bottom sash, with some members offering original glazing bars for accurate replication. Whilst glazing bars can be specified, our members would advise that period styled astragal bars meet the sympathetic replacement brief, and they have a number of case studies to provide reassurance of this.


Narrow cavity insulated glazing

Our members have a great deal of experience working with homeowners, architects and Conservation Officers. They appreciate that a significant conflict is between preserving the character of the original windows and doors, whilst improving levels of thermal efficiency. To meet everyone’s needs, a great deal of investment has been made in the advancement of narrow cavity insulated glazing units.

With slim sightlines, narrow cavity glazing provides a perfect solution for the pursuit of replication with improved energy efficiency. Those members who offer narrow cavity glazing ensure that the units meet the durability requirements of BS EN 1279. In addition to slim line glazing, some members also provide hand or machine-drawn glass to imitate historic crown and cylinder glass.

For more information, click here to download our advice note on narrow cavity insulated glazing.


Source heritage designs for sympathetic replacement of timber windows & doors

For advice and assistance on how to achieve sympathetic replacement, visit our Find a Supplier page. Alternatively, complete the web form (found below) and provide us with details of your project so that we can put you in touch with those members who can meet your specific project needs.