Stone wall insulation

Houses with random stone or coursed stone walls may have been built with a cavity which is suitable for cavity wall insulation.


They may however need a more thorough examination than ‘standard’ brick built properties particularly if it is in an town where we have no previous experience in that area.

If we have insulated properties in your area and/or the house type is familiar to us we would be fairly confident that there is a cavity.

When a property has an outer wall made of stone or irregular brick such as Accrington hand made traditional bricks, it is unlikely that the internal surface of the cavity will be smooth, in the way that a 'standard' brick wall is.


Stone walls and irregular cavities are therefore unlikely to be suitable for fibre since blown fibre cannot be guaranteed to fill the cavity evenly although it is perfectly suitable for brick cavity walls of which we have insulated thousands since our beginnings in 2001.


Random stone houses are usually not best suited for blown mineral fibre but not all stone built properties that have a cavity are necessarily suitable for injecting with insulation of any type. We can however assess what is and isn't suitable and advise accordingly.

Blown fibre is becoming increasingly discontinued as it has some inherent problems as well as being at a disadvantage from the outset.

Depending on your property type and suitability we can insulate the cavities with Polypearl Platinum bonded polybead insulation.

Brick built properties are generally classed as a standard install but there may be occasions when even a brick built building is not suitable for any kind of cavity wall insulation and we would always advise against installing if this is the case.

For home-owners of houses with random stone walls we recommend either a PU foam or graphite grey infused bonded bead as this offers excellent thermal properties and is suitable for random or coursed stone walls. It is also a far superior material that can be installed in 'standard' brick properties also.

For properties with stone walls a more detailed examination is required. Specifically we check, that for each elevation:

  • The cavity is of sufficient width to ensure it is fully filled with insulation, since by their nature random stone walls may have a very uneven cavity.

  • There are no obstructions in the cavity. If there are this can be rectified with remedial work ie. rubble removal and cavity cleaning

  • The type of tie that holds outer & inner leafs (walls) together

  • There is adequate sub-floor ventilation

  • There is no evidence of ‘bridging’ of the cavity, which would allow dampness to track accross from the outside to the inner wall.

In our experience random or coursed stone walls tend to be either:

  • Suitable for cavity wall insulation

  • Requiring some localised repair (e.g. resolving a dampness issue) before cavity insulation can be installed.

  • Not suitable for insulation (e.g. because of inconsistent cavity width, or obstructions).

As part of our survey we will look inside the cavity with a boroscope and advise you on the options available. Irrespective of property type a crucial requirement that we check for is ventilation from your heating or water system. If required we can fit a modern day specified primary air ventilator as well.

BBA & Green Deal is only accredited to brick built properties

Multi-Therm Insulations

Unit 12 Monksbridge Trading Estate

Outgang Lane, Dinnington

Sheffield, S25 3QZ

*BBA Installer 3633 - 2020

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