How AeroCork Insulation Helps Cold Walls in Bath Homes

If an outside-facing wall in your Bath home feels cold to the touch, the room takes ages to warm up or black mould keeps returning in the same corner, the wall surface may simply be too cold.

AeroCork is a thin internal insulating cork plaster. It is applied directly to suitable prepared walls, creating a seamless thermal layer around corners, window reveals and other awkward details. By improving the internal surface temperature of the treated wall, it helps create a warmer, more comfortable room and reduces the cold surface conditions that encourage condensation.

DSB Plastering & Wall Insulation installs AeroCork in Bath and the surrounding areas. We assess the wall first, prepare it properly, apply the cork system and finish it with a smooth plastered surface ready for decoration.

What is AeroCork insulation?

AeroCork is an internal plaster containing natural cork granules. Rather than being fixed in sheets, it follows the wall and forms a continuous coating. This makes it especially useful around bay windows, reveals, corners, chimney breasts and uneven solid walls where cold bridging can be difficult to treat neatly.

AeroCork has a declared thermal conductivity (lambda) of 0.04 W/mK — manufacturer technical information rather than a guaranteed result for every property. It is applied as a thin, continuous multi-coat system, commonly using two trowel-applied coats to build approximately 3–6 mm before the compatible plaster finish. The exact build-up depends on the wall, its condition and the agreed installation specification.

That slim build-up suits smaller rooms and older Bath homes where room proportions matter. For installation details and quotation information, visit our AeroCork insulation service in Bath page, or see how it went on a real DSB cork insulation job.

How cold walls lose heat in older Bath homes

Most older Bath properties were built with solid stone or solid brick walls. There is no cavity and no insulation layer, so the wall is a single continuous path between the heated room and the outside air. When it is cold and wet outside, that wall stays cold, and heat from the room moves steadily through it.

Heat is lost through every part of a house — the roof, the windows, the floor and draughts around openings — but the external walls are usually the single largest surface in contact with the outside. The illustration below is a general industry diagram of where heat typically escapes, not a measurement of your home. Every property is different, and only a survey can tell you what is happening in yours.

What homeowners actually notice in an uninsulated older house is fairly consistent:

• Outside-facing walls that feel cold to the touch even when the heating has been on
• Rooms that take a long time to warm up and cool down quickly once the heating goes off
• A cold, draughty feeling when sitting near an external wall or bay window
• Condensation forming on the coldest surfaces, often in corners and behind furniture
• Black-spot mould returning in the same places each winter after being wiped away
• Peeling paint, musty smells or damp-feeling plaster on the coldest walls

Corners, window reveals, bays and chimney breasts are usually the coldest spots because heat escapes through more than one direction at those points. That is why mould so often appears in exactly the same corner year after year, and why treating the whole wall surface — including the reveals — matters more than patching one patch of plaster.

Cold walls, condensation and mould

Warm indoor air carries moisture from cooking, washing, drying clothes and breathing. When that air meets a sufficiently cold wall, the moisture can condense on the surface, and repeated wetting creates the conditions in which mould can grow.

AeroCork raises the temperature of the treated internal wall surface, and a warmer surface can reduce the conditions that encourage surface condensation. It is not a guaranteed cure for every mould or damp problem. Ventilation, humidity control and sensible background heating still matter — extractor fans should be used, trickle vents left clear and rooms kept reasonably warm. Leaks, penetrating damp, failed pointing, defective gutters and other building defects must be resolved before an internal finish is installed, which is why DSB never simply covers a damp-looking wall. There is more on this on our cold walls and condensation page.

Where AeroCork works particularly well

AeroCork may be worth considering for:

• Cold solid external walls in older Bath properties
• Window reveals, bays and other areas affected by thermal bridging
• Bedrooms and living rooms that feel uncomfortable despite the heating being on
• Walls with recurring surface condensation or black-spot mould
• Uneven walls where a seamless trowel-applied system is useful
• Rooms where losing several centimetres to insulation boards would be difficult
• Properties that benefit from a vapour-permeable internal finish

Because it is trowel-applied, AeroCork follows uneven backgrounds and detailed areas to create a continuous layer. This makes it particularly well suited to targeted room upgrades and hard-to-treat cold walls, alongside the other internal wall insulation work we carry out.

A recent internal AeroCork installation

On this project, the external walls were cold and the customer wanted a warmer, smoother internal finish without constructing a bulky new wall.

After protecting the room, we prepared the background so the new system could bond correctly. AeroCork was then applied in two trowel-applied coats, carried continuously across the wall and into the window details, before the compatible smooth plaster finish left the room ready for decoration — a slim build-up with the vulnerable cold areas around the window properly treated.

The benefits

The benefits of AeroCork for your home

Questions

Frequently asked questions