Removing urea-formaldehyde foam cavity wall insulation

The use of urea-formaldehyde foam insulation was a popular choice in the late seventies and early eighties to help improve the energy efficiency of properties. This type of insulation could be injected into older cavity walls, where no existing cavity wall insulation was present – vastly improving the thermal performance of the wall.

Urea-formaldehyde was one of the first materials used to retrofit cavity walls with insulation. It was popular because it was easily injected (it goes in almost like shaving foam before setting solid) and so there was no impact on the appearance of the property.

An estimated 1.5 million properties were retro-fitted using urea-formaldehyde cavity wall insulation. Unfortunately it is becoming more and more common for this type of cavity wall insulation to fail. We are going to discuss the reason for this below.

Problems associated with urea-formaldehyde cavity wall insulation

When urea-formaldehyde was injected into old properties, it was as a mixture of foaming agent, resin and compressed air. The foam tended to solidify in just a few hours and then cure over the following week or so. The problem is that this type foam shrinks as it cures – and shrinks significantly. Often this issue only came to light when the homeowner revealed the cavity (by replacing windows etc.) but it meant that there were areas across the wall surface where there was no longer any insulation, resulting in cold bridging.

The other issue with urea-formaldehyde is that it also breaks down as it gets older, changing from a solid foam mass to a crumbly powder. This normally means the insulation slips down with the cavity leading to the same sort of issues associated with shrinking – cold spots across the wall area where there is no insulation.

The final issue with the urea-formaldehyde cavity wall insulation was the release of formaldehyde as it broke down – formaldehyde is proven to lead to a variety of adverse health effects impacting the eyes, nose, and respiratory system.

Extraction4Homes – getting to the root of the issue!

At Extraction4Homes, as you might expect we have a huge number of customers getting in touch with us regarding urea-formaldehyde. For us it was very important to find a method of helping this type of customer  – in terms of advice as well as introducing a safe procedure for removal or extraction of urea-formaldehyde from the walls.

It became apparent on our site surveys and specific investigations into this type of insulation that the breakdown of urea-formaldehyde was far more apparent in south-facing walls.  Our investigations suggest that this is a result of greater exposure to direct sunlight on these brick faces, increasing the working temperature of the urea-formaldehyde. This seems to have contributed to a much faster breakdown of the material over the years, reducing the urea-formaldehyde to a powdery dust. This theory was backed up by evidence from our surveys that commonly found almost perfect insulation within north facing walls (or in much better shape than the equivalent south facing wall of the same property).

So if customers come to us now regarding this type of cavity wall insulation, our first task is to confirm that this type of insulation really is in place.

Identification urea-formaldehyde within property

To an experienced surveyor, urea-formaldehyde injection holes can be seen within the mortar joints of the building – but over years of exposure to the elements, these injection holes can be very hard to identify.  The most common place to identify the urea-formaldehyde is within your loft area, which tends to be the most common location for overspill around the eaves of the roof due to the open cavity extending into this space.

By drilling a series of pilot holes around the building, we can also us a borescope camera to identify the urea-formaldehyde and confirm its current state.

If it is confirmed the urea-formaldehyde is within the cavities, we can then remove this if the customer so desires.

Safe removal urea-formaldehyde

Extracting or removing urea-formaldehyde from a property is no easy task, with many extractions companies refusing to undertake this type of work for many reasons including:

  • Timescales – removing this type of insulation takes time
  • Internal preparations – we need to be sure that the dust produced from the extraction work doesn’t enter the inside of the property
  • Sheer hard work – removing this type of insulation is far more difficult than other cavity wall insulation.

For us, preparation is absolutely key – we also inform the home owner of possible disruption, which may include moving out whilst the work is underway.

Our preparation includes the following activities:

Loft area – all eaves are sealed and missing brickwork is sealed within gable ends. We also cover all personal property with dust sheets – the aim is to contain the urea-formaldehyde as much as possible.

Windows & Doors – All windows and doors are taped and sealed with clear polythene plastic with the aim of containing the urea-formaldehyde and reducing exposure of formaldehyde to the the internal environment

Room Ventilation – Similar to windows and doors, all room ventilation is taped and sealed with clear polythene plastic – all gas and solid burning appliances should not be used while ventilation is blocked. We then perform a spillage test pre and post extraction to ensure the ventilation is still working as it should.

Other Services   – Overflow pipes, waster pipes, washing machine outlets and tumble dryer outlet are all covered to contain the urea formaldehyde.

Unfortunately it is almost impossible to contain the urea-formaldehyde 100% while the extraction process takes place, because the extraction process involves breaking down all the existing insulation into a fine white dust which is then vacuumed out of the cavity. However we try to minimise this best we can using the methods mentioned above.

Interested in using our services?

For more information regarding our survey packages and technical support for removal of urea-formaldehyde, please call us on o208 819 9152 or fill in the form below and one of our team will be in touch shortly.





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