Condensation and Cold Bridging
What is Cold Bridging?

Independent Surveyors solve problems

If you need help or advice with regard to your property free phone 0800 298 5424.

This article has been written by two Chartered Surveyors, a Chartered Builder, Chartered Building Engineer and an MSc student. It is based upon experience of property investigations and structural surveys that we have carried out and also property investment and property management that we were involved with. We have also presented and been guest lecturers at universities and written exams for the RICS and also been on the panel that approves Chartered Surveyors.

We have been expert witnesses in many cases relating to this matter, some of which have non-disclosure settlements, so we are concerned that the knowledge on cold bridging is not developing to this limitation.


We would of course be happy to carry out a building survey for you or a defects report, and as they say - no job is too large or too small, particularly in this interesting and developing area.If you need help or advice with regard to your property free phone 0800 298 5424.

Cold Bridging, a frequent problem

We have frequently come across Cold Bridging during our surveys. We can only see this becoming a bigger problem as we insulate our properties more and expect to live in warm tropical climates (inside) and don't understand how our environments and properties work.

We are happy to talk about any property matter whatsoever. Please feel free to phone for a friendly chat. This is just a reminder about our Free phone 0800 298 5424 number. Here is some more information about cold bridging.


Thermal image taken of metal window frame in a room where cold bridging was occurring


Cold frame with condensation visible on the metal return

What is cold bridging and how does it work?

Cold bridging is a term and a problem we feel will become much more common in years to come. We are finding more and more examples of Cold Bridging. This happens in certain types of property and to some extent it could be argued that it is a characteristic of that type of property and quite a complex issue to resolve. Unfortunately it means condensation is more likely.


Post war / 1950's property that cold
bridging can be a problem in

Cold Bridging

Cold bridging is caused by a colder element in the structure or fabric of the building allowing coldness to pass through. When warm moist air is present in the property and it passes through the colder elements of the structure we have what is known as Cold Bridging.

This is often caused by a combination of issues. It can occur from things such as having a shower or a bath, cooking or clothes washing, particularly if you are drying washing on the radiators.

It could, in commercial properties, be a large gathering of people breathing (this can cause a lot of humidity) in a building that has stood cold and empty for some time such as a church, village hall, sports centre or a crèche. These human atmospheres create a climate which can result in condensation on the cold elements of the structure and fabric if the room is not ventilated properly.

Clothes dried on radiators can cause
humidity and cold bridging

Certain types of buildings are more susceptible to Condensation and Cold Bridging

Here is our sketch on Cold Bridging

This is a good indication of the typical things that cause Cold Bridging in a house and how extraction from humidity generating areas such as the kitchen and the bathroom can reduce problems. You do need to look at how you live in the house.


Cold bridging and condensation

Cold Bridging isn't just about condensation on mirrors

Cold Bridging isn't just about condensation on mirrors. Not only can it be an original characteristic of the building it can be encouraged by all types of extension and alterations.

Cold bridging is far worse than condensation as it is caused by an element in the structure which you can do very little to change without great expense. If you buy a 1960's property for example, with concrete lintels that cause cold bridging, this is a characteristic of the property and it is very difficult to change. However not only could it be a characteristic of the building it could also be caused by alterations that you make to the building.

To give you some examples of Cold Bridging

As mentioned above typically Cold Bridging can be caused by lintels and also by beams (which effectively are big lintels). These were very commonly used in 1960's and 1970's buildings and can lead to condensation over doors and windows. We mentioned a 1960's building but here are some examples of concrete lintels that were commonly used in the 1970's and which today have caused cold bridging over the door and which in turn has led to condensation and deterioration of the paintwork.


A rear door to a 1970's building. Can
you tell where the cold bridging
would be in this photo?


A close up view showing there is a
concrete lintel over the door and
window. This is where the cold
bridging occurs causing
condensation inside

Cold Bridging can also occur on metal lintels. We note that some modern metal lintels now have insulation in them which we assume is to reduce cold bridging.

Surveying Articles we have written

Commercial properties suffer from Cold Bridging too

Commercial buildings are often built using structural frames. These frames are usually constructed of concrete or metal or sometimes both. The structural frame forms the skeleton of the building as you can see in the adjoining photo. Sometimes the structural frames, particularly, the concrete ones can suffer from Cold Bridging which causes blackening of the concrete frame. This can look like the roof has leaked and can lead to wrongly diagnosing a problem as being a roof leak This can result in great time and expense being wasted repairing a roof that was not leaking and indeed in some cases has led to a new roof being fitted which has cost tens of thousands of pounds. This happened because it wasn't understood what the problem was.


Cold Bridging in a commercial
property with a concrete frame

When is Cold Bridging Likely?

In our experience we have seen cold bridging occurring in

1. Georgian and Regency properties

2. Victorian and Edwardian properties

3. Pre-war properties

4. War years construction properties

5. Post war construction properties up to the 1980's.

6. Commercial properties that use structural frames particularly concrete frames.


Georgian style properties can suffer
from cold bridging and condensation.
However in our experience it is more
likely to be the new extensions or

alterations that are added to them

We find that cold bridging and condensation occur most commonly where a property has a relatively high heating level, a good level of insulation and where it has many occupants.


Post war 1960's properties with
plastic double glazing without trickle
vents that have been added can
cause condensation

Problems with 1970/1980 era properties relating to Cold Bridging

Let us take a look at the 1970's/1980's era of property to give an example of the problems we have come across with this era.

The 1970's is an era where we had just begun to think about insulating due to the oil crisis and where we added insulation into our structures

For example with;

1. cavity wall insulation or

2. double glazed windows.

This meant they were warmer which has meant the significance of a lintel, over a door or window, being colder and allowing the transfer of coldness becomes much more important. This results in condensation that we commonly see above windows in this age and era of property.


1970's property with cold bridging to the roof beams and the lintels


1980's property, cold bridging was found in the lintels

How to solve Cold Bridging

The difficulty is resolving cold bridging. Normally, where condensation is involved, if you get the balance of warm and coolness of the air, ventilation and movement you can reduce considerably the chances of condensation. Airing the room by opening the windows, which seems to have gone out of fashion, can help considerably.


Condensation and cold bridging

Where do we most commonly find Cold Bridging?

Our thoughts on this have very much changed as we used to say that cold bridging was typically found in properties from the 1960's/1970's. However we are increasingly finding it in a broader range of properties, particularly Victorian properties, where people are trying to live to modern standards of heating and insulation without understanding that the properties need to breathe as well. We have also found cold bridging in properties where extensions have been carried out and where the extension has been built to a different standard to the original property.


Victorian properties (roof
conversion circled) that have been
extended and altered over the years
with new thermal properties that
can cause Cold Bridging because of
the mix of old and new standards

Is your lifestyle a factor in Cold Bridging?

This is often a contentious and difficult question, particularly where the occupier is a tenant and there is a disagreement between the landlord and the occupier as to why there is mould in the property. In our experience the major factor is the size of the family living in a property. This is especially the case with large families with young children and where in turn there is a lot of washing of clothes being done. This is particularly the case in the winter months, with the wet washed clothes being dried on radiators. Also general hygiene washing and not to mention cooking to feed everyone all lead toward a more humid atmosphere.

This is generally known as the lifestyle of occupants and can be a major factor particularly where there are legal cases as to the problems within a property.

Expert witness case, what is an expert witness?

This is where you employ someone who is a specialist within a field, such as us as Building Surveyors, who comment on problems of condensation within the property. We have been involved in several court cases as expert witnesses where landlords are being taken to court over the condensation that is occurring in their property. The expert witness case looks at how this condensation is occurring and if it relates, for example, to the occupiers' lifestyle or whether it relates to the way the building was constructed and where there are, for example, cold bridging elements. When discussions of this nature take place in court they can be very expensive.


Older style London converted flats
with property problems such as
Condensation and Cold Bridging

Is Cold Bridging and Condensation a design problem or a lifestyle problem?

This really is a difficult question to answer. We have been involved in a number of cases as expert witnesses or advocates and the answer can vary. We would comment that there are factors that can be changed and factors that can't be changed. For example, the occupiers lifestyle can in most cases be amended. This may involve the occupier having an understanding of the problems they are causing. For example, drying lots of washing on a radiator inside may be causing excessive moisture in the atmosphere. Equally not opening the windows and closing or sealing up vents can be a problem.

Design of the Building

Sometimes it really is down to the design of the property. Where there are cold elements in it, such as a concrete structural frame or concrete lintels, when these are in contact with moist air condensation occurs. Sometimes this is impossible to stop but often it is possible to reduce it by having a better circulation of air with a better heat and coolness balance and the removal of any moist air.


Condensation can be improved by
adding extract fans

Things to remember about an air brick

If you are thinking about adding an air brick then you need to be aware that airbricks don't actually allow that much air through. Although externally a nine by three air brick has a lot of gaps, as these gaps taper, it is generally considered that only about one inch square of air regularly passes through the grills.


Air brick may not ventilate
room enough

What's happening in brand new housing?

It could be argued that we still do not know what is happening in brand new houses that are highly insulated. We have been involved in one legal case where a modern heat exchange system was being used where it was simply not possible to have a shower in the property without causing condensation, even with the windows open and taking other measures. Our concern is what is happening to this condensation? It was not visible on the surface so is it visible as interstitial condensation? We still think there will be problems to be found in modern properties.

As Surveyors we like to see things that have been is use for some time work before we would recommend them.


Photo of a typical new house

In the winter we have condensation problems but in the summer we don't

The different seasons mean that the building reacts differently. Anyone who has lived in an old property will know that windows and doors particularly sliding sash windows will swell during the winter months.

There can be similar issues with a property where, regardless of your lifestyle, during some of the different seasons, for example the winter or a wet spring, taking a shower can relate in condensation even with extract fans running (although this is far less likely).

It also depends on what the humidity level is outside as this can be greater than inside. The moisture/humidity will then seek out colder rooms such as spare bedrooms and the corners of cupboards. When you open these at a later date you will be surprised to find black mould.


Sliding sash windows can swell in
the winter months


Black mould on wall


Black mould on wall

Extensions and Cold Bridging

Increasingly we are coming across problems where properties have been extended and it has not been planned or thought through properly. We have come across dormer roofs that simply have no insulation so any heat in the property is going straight out of the dormer roof. We have also come across property problems where an extension has resulted in colder areas within the property and which although not problem areas, as such, our clients have found them not nice areas to be in. It is not a great outcome if you have just spent tens of thousands of pounds on a new extension that you are not happy with.


Dormer windows can cause cold
bridging if they have no insulation

Why should you have a building survey carried out before buying a property?

Caveat Emptor means Buyer Beware. This means it is the buyers responsibility to have a building survey carried out to establish if there are any problems with the property. The estate agent is unlikely to inform you of any.

What do our circles and ovals mean?

The circles and ovals that you will see in our articles and building survey reports are the system we have devised to explain in more detail any problems or characteristics that we find within a property.


An example of our ovals

Our Sketches

In addition to this if the photographs do not explain the problem enough, together with our survey report, we also add in one of our own sketches such as the example that is shown here


Airspace in the roof is vented by the
vents in the soffits

Our Good, Bad & Ugly Surveys!

After receiving feedback from our clients we have designed what we call our Good, Bad & Ugly survey. This is a building survey, also sometimes known as a structural survey, that has been developed over many years. The key factor, we believe, is that our surveys are easy to understand and written in plain English.

Examples of our building surveys

If are buying a property then you may like to see some examples of Building Surveys we have carried out. You will see that our surveys contain photos, sketches and definitions that help to explain the specific problems that we find within the property. There is also an Executive Summary at the start of the survey report that highlights the main issues that we find with the property. Please call us and we can email you some of these examples.

Independent Surveyors

If you truly do want an independent expert opinion from a Surveyor with regard to valuations, mortgages, mortgage companies, surveys, building surveys, structural report, engineers reports, specific defects report, structural surveys, home buyers reports or any other property matters please contact 0800 298 5424 for a friendly chat.

Commercial Property

If you have a commercial property, whether it is freehold or leasehold then sooner or later you may get involved with dilapidation claims. You may wish to look at our Dilapidations Website at and for Disputes go to our Disputes Help site

We trust you found the article of use and if you have any experiences that you believe should be added to this article that would benefit others, or you feel that some of the information that we have put is wrong then please do not pause to contact us (we are only human).

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