Condensation can appear when storing in shipping containers and during the inclement months of the year this can become more of an issue. There are a number of 
contributory factors that create this problem. To understand this problem in greater detail well endeavour to explain. Used shipping containers may have moisture in 
the floors from previous uses, and even new builds if left shut for prolonged periods may produce some moisture inside.
The biggest fact anyone needs to know is and ultimately digest is the fact that 
ISO SHIPPING CONTAINERS DO NOT CONDENSATE WHAT IS PLACED IN THEM CAUSES THE PROBLEM
Much is written and much is debated about this subject please read this section of our website to understand what causes and what solutions there are to avoid this 
issue. After many years in the industry we have become a seasoned veteran in this subject. It is the subject most self storage people discuss and do not understand 
Fabrication and Site Services UK have extensive shipping container background with over 30 years in the industry. See website www.fabandsite.co.uk for more  
information on us.
Our new build containers have vented doors and front panels, increased airflow reduces the opportunity to create moisture from damp or wet cargo. See our website 
The items you are storing may well contain moisture of some kind even a bed mattress has a moisture content. Other house hold items like dishwashers, clothing 
washing machines, fridges and freezers, even in winter or summer, will turn that moisture to vapour and as the temperature changes. Ultimately the result is that 
vapour will become water droplets that gather on the ceiling and start falling to the floor or on stored items. To help prevent this there are many views and suggestions 
about, but in reality the most successful method is the use of chemical dehumidifiers. 
These work very well as they either contain silica gel or desiccant clay depending on the product you buy. Shipping lines have always traditionally used gel packets 
within clothing containers and electrical goods transportation. However “dry poles” as they have become known do work well. The costs vary greatly but you should 
not pay any more than around £30.00 each. Our recommended supplier of these is us!! a very good and environmentally safe product supplier. Ours is the only EEC 
safety approved product on the market, with official EEC regulations set out on the instruction panel of each unit.
Manually insulating shipping containers with ply clad compressed foam works but it is costly to achieve. Take a look at www.welderjohn13.com our online shop for  
photos of insulated containers we build they are exceptionally good and have enormous insulated properties.
Equally there is another product proven to be helpful in this area this is like a spray on porridge type product which is water based. This seems a very strange way to 
eliminate moisture but it is very good in the short term. This insulates the roof internally keeping heat in and cold out. Please contact us if you wish to learn more 
Container moisture technical bulletin
When deciding whether a certain Shipping Container is suitable for transporting a certain cargo, it is vital for those involved to have sufficient knowledge about the 
anticipated climatic conditions in the Shipping Container. The three major factors which have a decisive impact upon the crypto climate (microclimate) in the Shipping 
Container are as follows : external climatic conditions, the type of Shipping Container and the cargo being transported.
External climatic conditions have a decisive impact upon the climatic conditions inside containers. The transport route in particular determines external climatic 
conditions, season and time of day and the current weather (rain, sunlight etc.). Due to the diversity of these factors, it is not straightforward to predict how the 
container climate will change in transit. It is not possible simply to transfer the experience gained from one transport operation to another, as the conditions prevailing 
in transit often vary greatly, but an awareness of how the factors interact is helpful in assessing transport risks. In a nutshell mother nature rules the roost.
The factors influencing Shipping Container climate are highlighted in greater detail below:
1. Temperature conditions in the container:
The temperatures encountered in containers are primarily determined by heat exchange across the container walls. Good heat-transfer properties, especially through 
the steel walls, and the relatively large ratio of container surface area to container volume have a favourable impact in this respect. There are reflective materials 
available on the market to reduce heat transfer, although expensive.
In addition to solar radiation, external air temperatures, wind and precipitation also have an impact upon temperatures. Due to the wide variation in levels of solar 
radiation over a day, considerable temperature variation also occurs inside the container. This particularly applies to the air layers located directly beneath the 
container roof, as this is where the effects of solar radiation are at their strongest and thus where the greatest heat exchange occurs. 
On exposure to precipitation, such as rain, the container roof likewise cools more rapidly than, for example, the sidewalls, and the underside of the roof thus cools 
down most readily. Overheating of the air inside the container, i.e. heating to above the external air temperature may be considerable even under normal weather 
conditions. In contrast, the variations in temperature of the cargo inside the container are less marked.
2. Humidity conditions in the container:
Humidity conditions in the container are primarily determined by internal factors, i.e. the prevailing conditions are largely determined by the hygroscopic 
characteristics of the cargo and its packaging. Hygroscopic auxiliary packaging materials, such as squared lumber for cargo securing, and the water content of the 
flooring may also play a significant part. Incoming outside air usually has no negative impact upon humidity. Since the temperature prevailing inside the container is 
generally higher than the outside temperature, incoming air would also reduce relative humidity. Seawater or rain may penetrate damaged containers. This constitutes 
a considerable potential risk. If the container is packed in wet weather (snow, rain), additional moisture may get into the container. 
As always the visual inspection of Shipping Containers is crucial for the safe transit of goods. Refer to our web site on Shipping Container inspection for useful pro-
active information. Any of our team will be able to offer services relating to repairs and inspection along with CSC certification. 
A LESSON IN INSULATION
Sprayed polyurethane foam is a tried and tested method of insulating steel shipping containers. We at Fabrication and Site Services UK have at our disposal a 
professional team who travel all over the UK and Europe to provide this service.
condensation in winter and help keep cooler in the summer months.  Manual foam boards do not fill the profile on the roof or sides, allowing on occasion condensation 
to form behind them. This is a cosmetically and good insulation method but has some degree of failure over time. Our systems can be sprayed into the profile, forming 
a composite air barrier with the steel and leaving no air gaps for condensation to occur.  We use two systems that will do the job, Elastospray and Walltite, which are 
both BBA approved. Thermal efficiency is comfortably achievable with our products. It is the Speed of application and the rapid quick to cure product that everyone 
wants and does not yet know about. Flexibility in its uses and in effect one product for many applications but in this instance shipping containers. We can solve 
almost any shipping container insulation & condensation problem with ease and at a very competitive price.
Polyurethane spray foam insulation is becoming widely recognised as one of the most versatile and efficient forms of thermal insulation around, achieving excellent 
results. Many self store companies recognise the huge importance of stopping once and for all the condensation issues with storage containers. It is important to 
understand that this method can also put an increase on value of your shipping containers. Typically increasing its value by some 40% makes this a very good 
purchase; we all know insulated containers carry high premium rates for sale. Equally in self storage applications this product gives customers confidence in long 
term storage within shipping containers storage of their worldly goods is protected from any possible moisture ingress.
Polyurethane spray foam insulation (Polyurethane) is used for shipping container insulation and is sprayed directly onto the surfaces where it bonds.  The high 
density foam bonds and holds firmly to the corrugated panels within the shipping container creating a seal to keep moisture at bay thus conserving the heat energy 
within the shipping container. Fabrication and Site Services UK provide a low cost yet very high performance shipping container insulation service. The process is 
controlled under the ISO 9001 Quality Control, meaning that all materials used in the foam are manufactured within the UK. These are applied using safe and reliable 
equipment, and the spray foam insulation itself achieves a certified class 1 fire rating. Our work is carried out in keeping with all UK and European HSE regulations 
and trade standards with minimum disruption. Having over 30 years experience in shipping containers, we have been successfully spray foam insulating all types of 
shipping containers’ for long term static self storage.
To summarise
Polyurethane sprayed foam insulation provides the ideal solution to shipping container s offering cost-effective, fast and reliable insulation for virtually any closed 
shipping container. Foam insulation applied to the interior of a shipping container will indeed provide outstanding thermal insulation values, and much higher acoustic 
insulation values. Spray insulation can also be applied to the outside of the roof, when used with specialised coatings, to seal and waterproof older leaking roofs and 
greatly increase thermal and acoustic insulation. This product is also available and is in effect liquidised rubber solution that we apply on the exterior to give longevity 
of shipping container roofs.
When applied to metal roofs, spray foam insulation can eliminate condensation with as little as 25 mm depth of foam. Using spray foam can eliminate condensation 
without having to replace or refurbish the roof, saving time, money and disruption and helping protect stock, machinery and anything stored within the shipping 
containers. Foam insulation also keeps all shipping containers cooler in summer as well as warmer in winter. Other applications you may consider for our products 
are as listed below:
 • Factories
 • Warehouses
 • Storerooms
 • Exhibition Halls
 • Showrooms
 • Manufacturing Units
 • Shops
 • Stadiums
 • Boats
 • Sheds
Please contact us to discuss this proven method of insulation all our details are on the home page contact us forms.