Something falling in cavity wall space? All manner of questions and solutions to problems and issues surrounding the subject of brickwork, blockwork and stonework

[abrin2007]

Over the last 6months or so I have heard what sounds like falling rubble dropping in the cavity wall of my house. House is approx 30years old, breezeblock / brick construction, no cavity wall insulation. A quick check of the external wall shows no obvious issues. I have noticed a few vertical cracks appearing in the internal plaster. Looking at the roof tiles from ground level there doesnt appear to be any damage and an inspection in the loft reveals nothing. Any suggestions ? Would I be best to approach a roofer or a builder for an inspection initially ?

[stoneyboy]

Hi abrin2007,
From the age of your property you probably have open cavities. Have you checked for vermin in your loft space, they my be disturbing debris causing it to fall down the cavity.
Regards S

[abrin2007]

Yes, it is an open cavity and I have checked the lost space for vermin but cannot seen any signs, droppings etc. Its the falling combined with the vertical cracks appearing in the plaster that are concerning me - I'm pretty sure vermin would cause cracking to plaster ? I have bought one of those cheap endoscope cameras off Amazon but the quality isn't brilliant to be able to show anything conclusive. Any other suggestions ?

[stoneyboy]

Hi abrin2007,
There is always the possibility that wall movement causes rubble to fall down the cavity so you need to check if the cracks are mobile. The easiest way for a diy person is to buy a strip of 4mm opaque glass 25x200mm with a score across the middle. Bond this to the wall over the crack using epoxy resin.
However I would still suggest that you have mice in the cavity and they are disturbing mortar snots on the wall ties. Is the activity day or night?
Regards S

[abrin2007]

The activity is usually when it is very windy or raining heavily which makes me think that there is water ingress coming from somewhere. I had my binoculars out again today looking at the roof tiles and I cannot see a problem there. I have also had a close look at the exterior mortar and cant see any issues. I dont mind paying to have a professional to come out and assess the situation - but what profession would be best to look at it ?. The cracks in the interior plaster are definitely growing, they started as hairline but are now 0.5mm

[stoneyboy]

Hi abtin2007,
Since the cracks are getting bigger I suggest you get a structural engineer in - ask your local building regulations department if they know of any locally.
Regards S