Drying out a flooded property

The process of drying a building after a flood can start immediately after the floodwater has receided. It is important that you contact us AS SOON AS POSSIBLE when you know you have a flooding problem, so that we can inspect your property and allocate equipment to you. We will deal directly with your insurance company and invoice them directly for all inspection, pumping, and drying costs.

The first stage of the process is for us to visit your property, and carry-out a thorough inspection so that we can determine the equipment required and the choices of drying method to recommend to your insurer (this is dependent on the age, style, and material of the building).

Once the flood is over, we will pump out the property using impellor and vacuum pumps, in order to remove all standing water within the property (and under the floorboards).

Once we have the standing water cleared, we will remove all contents from the affected area and begin drying the property using the method agreed with the appointed surveyor.

During the drying process, we will visit the property regularly to monitor the moisture levels, and will add, move, or remove equipment as necessary in order to ensure that the entire affected area is drying in the correct manner.

Once we are happy that the property is dry, we will ask the allocated surveyor to inspect the property and sign-off the drying phase, so that the renovation works can begin.

To understand the process in more detail, click on the bars below.

flood drying

Drying out a wet floor

flood drying equipment

Injection drying equipment

The first stage of the flood drying process is to extract the standing water by using submersible pumps and vacuum pumps.

Once the water is extracted and all wet materials and contents are stripped out, the drying of the building can begin. Drying out a property is essentially a process which involves evaporation from the surface of wet materials (walls, floors, ceiling, etc.) into air which is at a lower relative humidity than the material itself. The difference in the relative humidity between the materials and the surrounding air is what determines the speed of evaporation. There are three basic methods of drying, namely:

  • Drying naturally just using ventilation and possibly assisted by fans to increase air circulation. This is the slowest method of drying a building and can be severely affected by the prevailing ambient conditions (required warm ambient air with low humidity).
  • Convection drying using heat and ventilation. This method includes a high temperature “speed drying” method and traditional fan heaters but could also encompass use of the in situ heating system and open windows.
  • Dehumidification. The most common method is to use dehumidifiers and heaters. This needs to be done in a closed environment as it relies on creating an unnaturally dry atmosphere; the speed of drying is largely dependent on the capacity of the equipment relative to the space to be dried.

The choice of drying method is usually dependant on a variety of factors such as the building type, tolerance to further building damage, resources available and building. If speed of drying is the overriding consideration then there seems no doubt that the application of high heat with powerful ventilation and heat exchangers will be faster than other methods. However, there is still some doubt as to the possibility of damage to building contents and this method is not recommended for historic buildings. It is also clearly inappropriate in buildings which are partially occupied or which are attached with adjacent buildings occupied. The environmental issues surrounding the choice of methods may also have an influence. Drying methods may also be varied during the drying process as different phases are reached.

The drying method agreed by your surveyor and our our drying experts, will determine the type of equipment that we use, however in some circumstances availability of equipment may determine the method, especially likely following a major flood event.

To extract any standing water left in the property, a variety of pumps are used. Vacuum pumps can be fitted to a variety of delivery mechanisms including mats and wheeled devices which will extract moisture from floor coverings.

There are basically two types of dehumidifier: refrigerant and desiccant. Refrigerant dehumidifiers work by cooling down the air that it pulls in, and extracting the moisture in the air through condensation. Refrigerant dehumidifiers operate best between 15-28 centigrade and at 60-98% relative humidity. Desiccant dehumidifiers use chemicals which attract water (desiccants) to draw the moisture from the air. They operate best between 0-25 centigrade and 40-90% relative humidity. As you can see, desiccant dehumidifiers have a greater range of operation and can be used to push dry air into closed spaces, however refrigerant dehumidifiers are very effective in closed rooms with heating applied.

Heat allows greater moisture absorption by the air, so the warmer the air, the more moisture can be absorbed into it. However, the secret to drying is to pull the moisture into the air, and then to remove the moisture from the air, drying the air and allowing more moisture to be pulled into it. Hence when using just heat to dry flooded buildings it is essential to also ensure adequate ventilation and air movement as the warm saturated air needs to be evacuated, usually to the outside of the building. Fan heaters are often used or heaters accompanied by separate fans. Fuel based heaters should not be used as they actually add moisture and increase drying times. The available heaters vary by their power output and therefore by the temperature of air they supply and the speed in which moisture can be evaporated from building elements. They may vary from domestic sized fan heaters sited in each room to superheating trailers designed to heat multiple rooms over 60 centigrade. Superheating trailers can dry very quickly but may damage vulnerable elements. Alternatively it is possible to use the in situ heating, such as the central heating system.

Air movers
Moving air with or without heat assists drying. Air movers (fans to you or me) can create wide circulation or can be directed at particular areas. Pipes can be attached to specialist drying fans which can be pushed through drilled holes or vents in order to access voids, for example cavity walls. This is often called injection drying, and is a very effective way of pushing air into hard-to-access spaces.

Monitoring the drying process is necessary for two main reasons;  it enables better control of the environment and create and maintain the perfect drying conditions, and it also allows us to predict the end of the drying process.

In order to get meaningful results, the initial condition of the various elements of the building must be established and photographic records must be taken.

It is vitally important to restore the moisture level to the appropriate level for reinstatement and to be sure that restored components are not damaged by trapped moisture or high humidity levels; over-drying is as damaging to a building as under-drying. As with the drying process it may be that more than one moisture measurement technique will be used to test moisture in different materials and at different drying stages.

When the drying goals have been reached, we will issue a drying certificate to your insurance company, and a copy will also be provided to the reinstatement company.

Tangible Drying’s sister company, Tangible Building Solutions, are a specialist insurance building renovations company, and can provide a complete renovation and repair service for your flood damage.

Tangible are regulated by the FCA, and so are authorised to deal with your insurance company on your behalf, and will act in your interests, negotiating with your insurers and their Loss Adjuster, to ensure that your property is dried and renovated to the very highest quality, with no “painting over the cracks” short-cuts going on.

If you use Tangible Drying as your property drying contractor, you are free to use any building company you wish for your renovation work, but we would obviously like the opportunity to discuss how Tangible Building Solutions can provide you with a top quality service.

Bob ClementsFlood Drying