I bought a cheap Depstech endoscope from amazon. It's an impressive bit of kit for £30. The camera head is thin enough to fit though a lot of the little holes drilled in the wall for pipes and cables and heating vents. As your mobile phone is the viewing screen. Photos and videos can be taken while rummaging through a nook. For very narrow holes, there is a mirror attachment allowing you to survey the expanse of the cavity. I tried it out on the cavity above the combustion vent in the living room. The installers had neglected to put a sleave on the vent which means the cavity is easily accessible.  A correctly insulated cavity should be difficult to see anything due to presence of dense insulation. But here there was a large void above the combustion vent. The picture below shows a reason for the void: A long wooden baton sits in the cavity obliquely and rests against a fish tail walltie. The baton has probably fallen into the cavity when the roof wa...

It has been a month and a half since I asked CIGA to explain why they thought arbitration was an acceptable option given that they had done a completely inadequate technical assessment. In a previous blog I had documented that the problem cavity was narrower in places than the 50mm mandated by building control and the BAA certificate. The technical manager at CIGA visited and did nothing but take photos of the building and try to verify the cavity depth. Initially he borrowed my tiny flexible measuring tape (which of course bends and so over estimates the cavity depth) and then tried to hook it on to the edge of the brick in the hole to get the size of the brick. In another spot he used a drill bit and his thumb and subtracted the brick that he measured earlier and in both instances came up with a figure of 55mm. I told him I didn't trust his methods as they didn't match up with my own when measuring the imperial brick which confirmed a standard imperial brick size of 110mm...

Once the cavity wall insulation is removed from the walls we are looking to replace the render on the house for a uniform finish. I was disconcerted by information I discovered regarding thermal requirements imposed during rendering. https://www.planningportal.co.uk/info/200130/common_projects/18/external_walls/2 Where 25 per cent or more of an external wall is re-rendered, re-clad, re-plastered or re-lined internally or where 25 per cent or more of the external leaf of a wall is rebuilt, the regulations would normally apply and the thermal insulation would normally have to be improved. Does this really mean that I would have to consider installing more insulation before I am allowed to render the house? The planning portal says 'have to be improved' - which is what we are doing by removing the wet insulation.

This does not look good. I'm not a materials expert but it looks like this is a poor match for the rough cast render. My basic understanding is that if you stick two materials together of very different composition then they expand and contract at different rates. Add to this different moisture and vapour permeability and there will inevitably be problems. It does look like the rendering on our house started to deteriorate after the CWI was installed. To the layman, it seems quite obvious that drilling random holes into your house is a terrible idea.

I wrote to CIGA explaining that the 25 year guarantee certificate does not mention anything about the how having a cavity full of wool changes the mode of failure in terms of water ingress compared ot the original empty cavity. It's a well accepted fact that cavity walls were designed to keep the water away from the inner leaf and problems arise when anything other than air sits in the cavity providing a bridge that could result in water ingress. If you have cracks in the render then it may cause some water to enter to the inner surface of the external wall just as with wind driven rain. However the presence of insulation material can lead to bridging and penetration into the inner leaf, particularly if it there are gaps.  In the case of wool it can become saturated and never dry out leading to an obvious damp mass which readily transfers to the inner leaf. I argue that with cavity full of wool, the mode of failure when presented with severe weather, or cracks in the mortar is c...

While awaiting the CIGA inspector number 2. I thought I would try to grow some microherbs on the wool, since my tests have shown that it seems to hold water from evaporating rather well. Rock wool is used in hydroponics because the structure can hold large amounts of water and air for developing roots and provided a good 3d structure to support them. For simple cress, it works marvellously. With just one initial watering of the insulation the cress was able to grow and complete it's life cycle on a 30degree day. From what I understand rock wool for hydroponics has been treated to bring the pH to a foliage friendly range. Not sure about glass wool. Egg and cress roll anyone?

CIGA agreed that my insulation needed to be removed, but then took no responsibility for it! I pointed out that it was an illegal install into a narrow cavity and repeated it 3 times before they replied: Despite your references to a less than adequate cavity width this has no relevance to the lack of maintenance which has resulted in compromised insulation and internal décor damage. What does less than adequate mean? Inadequate. Here are some other words from the thesaurus entry for inadequate : -  deficient, faulty, incompetent, incomplete, lacking. I asked them if I could remove the material myself and then claim the cost back through arbitration. "The CIGA guarantee covers the insulation in your property, once the cavity wall insulation has been removed there will no longer be a guarantee on your property. If there is no guarantee on the property the arbitration process isn’t available." This is insane. They know there is a problem and the internal de...