Cavity Wall insulation Removal

Why Remove Cavity Wall Insulation ?

We all know that cavity wall insulation is the best way to reduce your domestic energy bills, helping you to maintain heat in your home and ensure that it stays warm, helping you to feel comfortable. However, not all cavity wall insulation lasts long, meaning that you may need to replace and install it with a new product.

There are lots of issues that may arise if it is not properly installed by your installer. Among these problems include damp walls or mould. Because of this, Extract Insulation wants to help homeowners, social housing and home builders alike that suffer from such insulation problems. We are the professional whom you can trust when it comes to Cavity wall insulation removal services.

We can assure you that we can effectively remove your faulty cavity wall insulation using our technological insulation removal machine.

While some materials stand the test of time, others like fibre do not:

  • Urea formaldehyde foam deteriorates over time causing the foam to shrink and cause voids in the insulation. In the winter months, stains may appear on the walls and high levels of humidity can cause condensation and mould to grow.
  • Fibre has been proven to absorb water. While the material is water resistant, it is not waterproof. Soaking wet insulation caused by wind driven rain has been found throughout England & Wales. Mainly since the storms of 2012/2013 and recent flooding.

Whatever kind of problems you have, whether it is an incorrect install, deterioration, voids in the cavity or wet insulation, we have the perfect solution for it. We can provide you with an effective process of Cavity wall insulation removal that will be ensured to bring positive results.

Insulation Problems

Damp Walls




Can Cavity Wall Insulation Be Removed ?

Yes, we use the latest machinery to remove the insulation safely and effectively. It’s not just about the tools & equipment, but about the people and experience using them.

We have been at the forefront of developing a system design, now used by others.

We are a long way from using drainage rods and a Henry hoover in the cavity, although these practices do still go on…

More info on the complete process can be found here.

How We Remove Cavity Wall Insulation ?

  • Take a brick out at the bottom of the property using an arbortech allsaw. This specialist tool allows us to save the original bricks so we can put them back in when we are done.
  • Drill the existing wall insulation injection holes out but only using a 14mm hole not the standard 22mm. (Additional holes may be required above windows as this is a trap area for the insulation).
  • An extra row, 3 bricks above the damp proof course (D.P.C) is also needed to ensure all cavity wall fill is pushed towards – and sucked out by – the cavity wall extraction hoover, ensuring no insulation remains above the D.P.C.
  • Starting at the first hole, closest to the industrial Hoover (where the brick was removed), we use compressed air to force the insulation towards the hoover. This causes a gap in the insulation which allows the material to be sucked out. We then move a level above, to force the next section to the gap below and continue to repeat the process, forcing all the insulation downwards and out via our extraction hoover.
  • The extracted material is bagged on-site and removed under a waste carrier’s license.
  • The property is then checked with a boroscope to make sure the cavity wall insulation is removed. A specialist attachment can also be used to link the boroscope to an iPhone. This allows us to take photos and videos of the inside of the cavity, which then allows our customers to properly inspect our work, and ensure all insulation is removed for themselves. These pictures and videos can be retained for you records.
  • All flues, chimneys and gas vents are checked by a competent & accredited person.

Removing damaged insulation or wet cavity wall insulation should be done by a reputable insulation contractor.

What Problems Could We Expect ?

  • We carry out a complete assessment prior to the extraction, inspecting the insulation and the property for its condition. Sometimes, however, unforeseen elements are found, such as rubble or debris in the cavity. These would have to be cleared, especially if you are looking to replace your cavity wall insulation after the extraction.Most rubble will come out during the cavity wall extraction process, providing you use a well-trained & experienced extraction technician. Should more rubble/debris be found, over and above what we were originally expecting, we will advise you accordingly. It may be something we can help with, or you could get a suitable trade in.Besides the rubble, in the past we have even come across a scaffold board, window trim & even an old wallet inside the cavity.

Some questions you might have

I propery is damp - Is it my cavity wall insulation?

Damp can certainly be caused by either incorrectly fitted insulation, or insulation that was simply installed a number of years ago. In the former case there are a plethora of poor practises that could have led to damp issues (such as incorrect materials being used, too much of a gap being left between the insulation and the space that surrounds it and debris being left within the cavity); in the latter instance it could be that the old insulation has simply slumped down, leading to the revealing of cold sports and the consequent forming of condensation.

You can find further general guidance upon the issue of damp on our blog, however for a full, professional opinion you should contact our team. They can reached directly on 0239 388 0032, emailed via or you can alternatively send us a message via our contact page.

When does cavity wall insultion need to be removed?

Beyond incorrectly fitted or old and ineffective cavity wall insulation not preforming, there are a number of other reasons that may mean your insulation should be removed and re-fitted, these include:

  • Where Urea Formaldehyde insulation is in use;
  • Where there has been flood/water damage caused to the insulation;
  • Where the cavity wall insulation has been installed within an unsuitable building type;
    1. Where the property has a steel framed.
    2. Where the property is timber framed

Note – Read more about why cavity wall insulation should be removed

How do we check the cavity wall insulation?

We have a wide range of non-invasive and invasive survey methods for assessing whether CWI extraction is required, including:

Non-invasive methods: Borescope inspection, Thermal Imagery and Moisture & Damp meters.

Invasive methods: Brick removal.

Read more about our survey methods on our ‘How do you detect & diagnose the problem‘ page.

Why are steel & timber framed properties not suitable for CWI?

Steel framed homes are absolutely not suitable for CWI; in fact often these properties, where CWI is installed, have been unable to have a mortgage granted for them as the surveyors deem insulation a serious risk to the steel or timber frame. The reasoning behind this is that, if the insulation were to become damp, it could lead to the corrosion of the frame – ultimately over time making the building potentially unstable.

Similarly timber framed properties could experience a rotting of the frame, what’s more both steel and timber frame properties require sufficient air circulation in order to avoid damp, rotting or corrosion.

In both instances excavation is essential; find out more about our Cavity Wall Insulation Removal Service.

Are any other properties unsuitable for cavity wall insulation?

Our experience within the industry has led us to discover a wide range of properties where cavity wall insulation has proven to be problematic, including:

  • Properties where there are elevations that are exposed to the elements and partially effected by wind driven rain;
  • Timber framed properties;
  • Steel framed properties;
  • Properties where incorrectly fitted or poor quality rain water goods have been used;
  • Properties that have experienced crumbling mortar (which should have been re-pointed prior to any CWI insulation);
  • Properties where rising damp was already being experienced;
  • Certain properties where raked mortar joints are used;
  • Properties where the cavity wall space is either under a measurement of 40mm, or over a measurement of 150mm;
  • Properties where debris, mortar, broken bricks or rubble was left within the cavity.

If any of the above apply to you then you may already be experiencing some of the common issues that accompany incorrectly fitted cavity wall insulation. Read more about this on our ‘Why remove CWI?’ page, or contact the Extract Insulation team for professional (and free from obligation) advice.

Why does rubble & debris cause issuses with cavity wall insulation?

One of the most common causes of issues with cavity wall insulation that could otherwise have been avoided is linked to debris such as brick ends, mortar or rubble being left behind within the cavity.

This happens as these items (known within the industry as ‘snots’) lie at the foot of a wall within the cavity ties. Usually, as rainfall hits the exterior of a property, the ties will guide the water away ready for evaporation, however when these ties are blocked by snots the moisture cannot escape – and instead seeps into the inner wall and eventually turns into a damp spot.

One of the most effective ways of establishing whether a cavity wall has been compromised in such a way is through Thermal imaging; read more about this on our ‘How do you detect & diagnose the problem’ page.

Can i remove cavity wall insulation myself?

DIY cavity wall insulation is not recommended, just extracting insulation from parts of the walls could do more damage than good. We use specialist cavity wall extraction machine & boroscope inspection cameras to check the cavity is clear after removal. Unfortunately you cannot rent the insulation removal machines, as the costs of the insulation machine is £3500 plus vat, it is more cost effective to employee an experienced insulation removal contractor like Extract insulation ltd.

How do you extract cavity wall insulation?

Many of our customers initially contact us to find out whether the removal of their cavity wall insulation is possible, and if so how we go about doing such a job.

In every instance we say that yes, if you have cavity wall insulation installed then we can absolutely remove it, and the process that we would follow would be:

  1. Inspect the site both on the inside and the outside of the property. This inspection will most notably be looking for any cracks that have become apparent where dust, debris and insolation particles can enter the home. If we do find any such cracks we then seal these before proceeding further with the job.
  2. We will remove bricks to allow us access to the cavity (in the cases of rendered properties we would instead drill ‘core’ holes’.
  3. We use an industrial grade vacuum (designed especially for cavity wall insulation extractions) and insert the nozzle into the cavity; this is coupled with a machine that blows air into the cavity, and together the two work in tandem to clear out the old insulation. Often we couple this with other removal tools, such as an item known as the whip.
  4. Once the cleaning process is complete with all debris removed we then take a closer look at the cavity using a camera on a rod, known as a Borescope – this simply confirms that we’ve cleared every last mortar piece and brick end out.
  5. We then replace and re-point the bricks and drill holes – being sure to use the right colour for a seamless finish.
  6. Finally we undertake an inspection of the work and ensure that we leave the property spick and span with both an inside and outside tidy up.

If the cavity is to be re-filled with insulation we generally leave the cavity to breath for around two months to ensure that it has properly dried out.

Find out more about our cavity wall insulation extraction service.

How much does cavity wall insulation removal cost?

The costs for cavity wall insulation and removal vary considerably from project to project, property to property. We provide general guidelines as to typical rates over on our ‘The Costs of extracting CWI’ page.

For a full and completely free from obligation chat about how much your cavity wall insolation project may be get in touch with the team. Head on over to our contact page, call them on 0239 388 0032 or email them via