Buying a 1950s house – bay windows – cracking and heat loss

The 1950s was a period of extensive house building following a lack of new housing during the Second World War.  Traditionally built housing of the 1950s is characterised by cavity walls, fireplaces to the main living rooms and bay windows at the front which would provide extra light to the main reception room and the bedroom above.

This article focuses on bay windows of a traditionally built 1950s house.

1950s house – cracking around bay windows

It is normal for a building to settle slightly following construction, but cracking can occur where different parts of a building settle at a different rate.   Typically, in a 1950s house, the footings of a bay window will be shallower than the footings of the rest of the house and this can result in differential settlement.  Hence, it is common for cracking to occur at the junction between a bay window and the main part of the house.

If movement is minor and not progressive then cracks can be filled.  Check regularly for any signs of further movement.

If movement is excessive and/or progressive then it is possible that a mortgage valuer may request a report on the movement by a Chartered Building Surveyor or a Chartered Structural Engineer as a condition of the mortgage.  The valuer may even choose to recommend a retention is placed on the mortgage until investigations/works have been carried out.  Note that the Valuer’s duty is to report to the mortgage lender and not to the purchaser, ie, you.

Consider instructing a surveyor to inspect the whole of the building and report to you as there may be other issues of which you should be aware before deciding to go ahead with the purchase.

If you are not seeking a mortgage but have a survey carried out on your behalf then your surveyor will report on whether he or she considers whether any movement is progressive or not, and whether any further investigations and/or remedial works should be carried out.

1950s house – heat loss through bay windows

The wall structure to bay windows is often of lighter construction than the walls to the main part of the house.  Sometimes the walls are timber framed, possibly with vertical tile hanging, and sometimes the walls are of a single narrow leaf of masonry.  Such construction can lead to high heat loss through the wall and/or condensation on the wall surface internally.  Heat loss from the room will also be high if the house has single glazed windows.  Condensation on internal wall surfaces is often identified by dampness and/or mould.  However, if this is noted on a house that you are considering buying then this is not generally a major issue as in many instances the walls can be upgraded with insulation.  If you propose to replace the windows to the bay then this is an ideal time to check the construction of the wall to the bay and upgrade with additional insulation.


  1. Check for signs of movement, such as cracking, to any bay windows.
  2. Obtain advice from a surveyor or engineer to determine whether the movement is minor or needs remedial works/monitoring (remember that the mortgage valuation is not a survey).
  3. Obtain written details from the vendor for any works carried out, such as underpinning.
  4. If there is significant movement (or if significant works have been carried out in the past) then bring these to the attention of your proposed buildings insurer and check whether any restrictions will be imposed on your policy.
  5. Check the thickness of any walls to bay windows. Check whether surfaces are cold and whether there are any signs of condensation, eg, mould.

See also How much does a survey cost? and  What should I do after having a survey?


Share This:

Buying a house with double glazing – misted units, ventilation, condensation

When buying a house with double glazing you might think great, no draughts, lower heat loss, etc.  However, double glazed units can fail and require replacement, particularly older units.

Double glazed windows have now been in use for several decades.  Early double glazing was often in either a timber frame or a metal frame, sometimes with insulation within the frame members.  Some of the older units had narrow sealed units which were not as effective against heat loss as more modern units.  Today, the vast majority of double glazed windows, whether replacement windows or used in new housing, have PVCu frames.

Double glazing is virtually essential for a modern dwelling to enable it to meet the requirements of Building Regulations in respect of heat loss.   The sealed air gap (filled with air or another insulating gas) between the two panes of glass reduces heat loss from the dwelling and prevents condensation on the glass itself.

When buying a house with double glazing it is important to check for the following:


Failed double glazed units

The sealed double glazed unit can fail either due to a defect in manufacture, damage or deterioration over time.  This can be identified by misting/fogging, ie, condensation occurring between the two panes of glass which form the double glazed unit.  The amount of misting can vary from day to day depending on weather conditions.   Once a sealed double glazed unit has failed it cannot be repaired.  It may be possible to replace the unit only, or it may be necessary to replace the whole window.  If only one or a small number of units have failed then other units of the same age may fail in the not too distant future.

If you are buying a house with double glazing and note one or more failed double glazed units, ask the vendor when the windows were installed and check whether there is a warranty to cover failure.  If there is a valid warranty, check whether this can be transferred into your name.

If the whole window requires replacement then contact a FENSA contractor to obtain a quotation and replace to ensure that the work is carried out in accordance with Building Regulations.


Insufficient ventilation

The purpose of double glazing is to reduce heat loss, reduce the risk of condensation on the glazing and help to maintain a comfortable temperature within the home.  However, as homes have become better insulated they sometimes suffer condensation due to a lack of ventilation.  It is important to provide adequate ventilation to a dwelling to allow excess moisture to escape and reduce the risk of dampness, condensation and mould.  Condensation isn’t simply water running down a window, it can also occur within furnishings resulting in dampness, a musty smell and possibly mould spores within the fabric.

Ideally, windows should have a combination of large opening casements and smaller top hung opening vent lights.  Windows should have locks so that they can be locked in an open position without reducing security, enabling windows to be left slightly open at night to prevent a build-up of moisture.  If there is mould on window frames and around window openings then this is a sign of inadequate ventilation.

If you are buying a house with double glazing, check whether trickle vents are provided.  Trickle vents allow background ventilation and can help to avoid a build-up of moisture and the risk of condensation.



  1. Check the configuration of opening windows.
  2. Check whether windows can be locked in an open position.
  3. Check whether there are trickle vents (usually found in the head of the window frame).
  4. Check the working order of window handles.
  5. Check whether there is any misting or fogging within the double glazed units.
  6. Check that any replacement windows have been installed by a FENSA contractor (if replaced since April 2002).
  7. Check whether there is a warranty for any replacement double glazed windows or doors and whether this can be transferred into your name

See also buying a refurbished house. 

Share This: