How to Insulate Interior Walls in 3 Simple Steps

By Jamie Orr
Date 10/12/2020
how to insulate interior walls in 3 simple steps

Insulation is a vital feature for any building. It reduces heat loss, improves energy efficiency and can even prevent the build-up of condensation, damp and mould. As you can expect, walls play a key part in this. But how do you insulate them on the inside without requiring extensive work?

Why insulation matters for walls

Walls are an essential part of every building’s thermal envelope. Along with the roof, windows, doors and floor, they’re responsible for keeping heat inside.

But as the saying goes, a chain is only as strong as its weakest link. If your walls aren’t keeping heat in, they will let the rest of the thermal envelope down. The result is a house that’s near impossible to keep warm without seeing your energy bills skyrocket.

Ever find your home’s temperature plummeting soon after the heating is switched off? Or maybe your house gets as cold as the outdoors on days where you wouldn’t expect to need the help of radiators? Your walls could be to blame.

Over time, poorly insulated walls can cause further problems with condensation, damp and even mould. Why? There are two reasons.

Firstly, uninsulated walls make it much harder (and more expensive) to keep your entire home warm – as we’ve mentioned above. When the air inside your home gets cold, it holds less moisture. That moisture has to go somewhere – and the destination is often your walls.

The second way uninsulated walls contribute to condensation is because they provide a cold surface. This is like a magnet to condensation. When it settles on them, they can become damp, which provides the ideal breeding ground for mould.

As well as being unsightly, this could lead to health problems, particularly for those with pre-existing respiratory conditions like asthma. To avoid a build up of damp and mould, homes need proper ventilation to let moisture escape, especially in kitchens and bathrooms. This includes extractor fans, vents and windows. However, ventilation doesn’t always do the trick on its own, and wall insulation is a great way to further protect your house.

The problem with most internal wall insulation

When walls are poorly insulated, one of the most well-known solutions is cavity wall insulation. This is a pretty big job which involves drilling holes into a wall to inject insulation before sealing.

Unfortunately, cavity wall insulation is unsuitable for areas with wind-driven rain, as external brickwork can be soaked.

It’s also unsuitable for any solid walls, which are made from brick or stone without a cavity.

Instead, solid walls can be insulated using boards or panels, before plastering on top of the boards. Again, this isn’t ideal because all the fixtures and fittings need to be removed. We’re talking about plug sockets, light switches, skirting boards and even doorframes.

The boards are also very thick, so they eat away at the size of the room. While a 100mm board might not seem that thick, it can have a noticeable impact when applied to all multiple walls in your home.

Additionally, insulation boards are susceptible to thermal bridging. Also known as cold bridges, thermal bridges are weak points in a wall’s insulation where heat can escape. This can happen where two insulation boards meet, for example, if installation isn’t flawless.

How to insulate interior walls easily

Thankfully, there is an alternative. SprayCork internal coating can provide an insulative layer without the need to remove fixtures or add bulky boards or panels. Here’s how…

1. Preparation

Walls will need to be cleaned down with a specialist bleach wash. This is simply to remove any dirt, dust and mould so the spray coating can adhere perfectly. It will also eradicate any mould build-up before treatment. Fortunately, the entire process is handled by a fully trained applicator, who has been approved by CorkSol ourselves. So, you don’t need to worry about laborious preparation.

2. Cork spray

Next, the walls will require two coats of a fine-grain sprayed cork solution. Each coat is 3mm in depth with even, continuous coverage across the wall’s surface. This eliminates any risk of thermal bridging, as the entire wall is covered in a single coat.

Because it’s so thin, there’s no need to remove skirting boards and coving or adjust switches and sockets. That means a quicker job with less disruption to your day-to-day life. Because SprayCork doesn’t contain any chemicals, it’s also perfectly safe to apply even when you’re in the house.

3. Overskim

Finally, the wall can be finished with a standard 2mm skim of plaster. This takes the overall depth of the insulation job to just 8mm, with the two layers of CorkSpray providing effective, invisible insulation.

That’s less than 10% of the depth of many insulation boards, so there’s practically no impact on the size of your living space. A CorkSol approved applicator will take care of the plaster overskim too, so you have a finished surface that’s ready to decorate (once the plaster is dry) without the need to arrange more work.

Does it really work?

Absolutely. When used to insulate interior walls, SprayCork has been found to reduce heat loss by up to 30%. But that’s not all. With SprayCork, you also benefit from:

  • Sound insulation – the coating absorbs up to 38dB of noise to make your home more peaceful.
  • Moisture-resistance – as well as walls being warmer, damp won’t be able to form on them.
  • Sustainability – the cork used in our products contributes to CO2 absorption, as well as saving energy once applied.
  • Breathable – SprayCork is fully breathable, making it suitable for both permeable and impermeable walls.

Put SprayCork to the test

CorkSol’s innovative SprayCork coating provides high-performance insulation without the hassle of cavity wall insulation or the bulk of insulation panels. Ready to put it to the test? Find an approved applicator near you, who is fully trained to get the best results using CorkSol products.

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