cavity wall insulation pros and cons

by Ms. Aurelia Harvey Published 3 years ago Updated 3 years ago

Pros:

Cost-effective and easy-to-install
Optional facing acts to support vapor barrier Cons
Glass fibers can irritate lungs, eyes and skin, which can cause lung-health issues
Performance suffers with poor installation technique (rips, tears and open spaces)
Best used in warm climates to reflect heat; good for wrapping pipes and duct work

Full Answer

What are the disadvantages of cavity wall insulation?

Another disadvantage of cavity wall insulation is the risk of hiring inexperienced installers who will do substandard work and use lesser materials than what is really needed. If quality of work is poor, this can result to dampness and eventually mold build up. 3.

Does cavity wall insulation save energy?

According to the Energy Saving Trust, uninsulated walls account for almost a third of the heat lost from a home. That means fitting cavity wall insulation is a great chance to slash your energy bills and save energy at home. It’s also one of the most cost-effective and long-lasting upgrades you can make.

What are the pros and cons of insulation?

They include all of the positives that come with insulation, such as saving money on heating and cooling electricity and gas, and a more comfortable home that maintains temperature better.

Does cavity wall insulation prevent mold build up?

With the cavity wall that is insulated, water will be trapped in between and will just run down the ground or above the windows instead of going through the inner wall and let moisture in. With lesser or no moisture, molds will not build up on the walls inside the home.

What are the downsides of cavity wall insulation?

General Cavity Insulation Disadvantages: If moisture gets into your cavity insulation, its ability to keep your home warm will diminish. Cavity fill insulation means you'll no longer have a void in the cavity to prevent moisture getting across to the inner leaf of the wall. If poorly fitted it won't be as effective.

Should I avoid cavity wall insulation?

After the cavities within the walls are filled with insulation these un-insulated elements may be significantly colder than the surrounding walls. This coupled with the effects of a draughty house, can create the right conditions for condensation and mould, often where it's not been seen before.

Is cavity wall insulation a good idea?

The main reason is because cavity wall insulation is a recommended home improvement. It has been proven that having good insulation can reduce heat loss through the house walls by up to 35%.18-Feb-2021

What are the disadvantages of insulation?

CONSShould be installed by professionals.More expensive than other types of insulation.Must vacate your home for at least 12 hours during installation.Poorly mixed chemicals can lead to health risks and ineffective insulation.

Does cavity wall insulation make a mess?

Many cavity walls can be insulated by injecting insulation material into the cavity from the outside. ... A professional can do the job in around two hours for an average house with easily accessible walls. It shouldn't make any mess.

Can old cavity wall insulation be removed?

The good news is that cavity wall insulation can be removed with minimal fuss. If suitable/appropriate, new insulation can be injected into the cavity or a completely different type of wall insulation can by used leaving the cavity empty (e.g. external wall insulation).11-Apr-2014

Does cavity wall insulation cause mould?

Assembly Members discussed the problem in the Senedd on Wednesday. If installed incorrectly, or in unsuitable properties, cavity wall insulation (CWI) can lead to damp.29-Nov-2017

How long does cavity wall insulation last for?

How long does cavity wall insulation last? ROCKWOOL cavity wall insulation has a proven lifetime of over 50 years.

Can cavity wall insulation make your house colder?

Even when insulation is not affected by rain penetration from the outer wall because the outer wall bricks and mortar are in excellent condition, filling your cavity wall with insulation of any kind can result in damp if the insulation is installed where full and proper pre-checks and treatment where required are not ...25-May-2018

What type of cavity wall insulation is best?

Foam Foam insulationFoam. Foam insulation, typically made of polyurethane, has been hailed as the best thermal cavity wall insulation.

What are the advantages of cavity wall?

Advantages of Cavity WallsCavity walls give better thermal insulation than solid walls. ... Economically they are cheaper than solid walls.Moisture content in outer atmosphere is does not allowed to enter because of hollow space between leaves. ... They also act as good sound insulators.More items...•03-Nov-2016

What are the benefits of cavity wall insulation?

Cavity wall insulation is one of the easiest and most cost-effective forms of insulation to install in the home. It increases the energy efficiency of your home, reduces heat loss and your carbon footprint, and can make the home warmer and cheaper to heat.01-Jun-2021

Why are cavity walls important?

It keeps the interior of the building dry and safe from damage or moisture build-up. Since cavity walls were designed to “air-out” moisture, this was a great design that limited exposure of the inner walls to rain. Having a gap where airflow slowly goes through can also be a form of insulation for a cavity wall.

How wide should a cavity be for insulation?

The criteria for installing insulation in a cavity wall include having an unfilled cavity space in the wall, having a cavity of at least 2 inches (50mm) in width – preferably wider – having masonry walls in good condition, and having walls that are not overly exposed to wind-driven rain.

What is a cavity wall?

A cavity wall is a wall with a hollow opening between two partitions or walls. These walls, or masonry wythes, are commonly referred to as “skins” and are usually made of stone, brick, or some other sort of masonry. The space between the masonry wythes or “skins” is a slight gap, commonly only a few inches in width, that is known as the cavity.

What is the purpose of air gaps in a cavity wall?

The idea is that the air gap serves as a thermal break and allows for condensation to drain away harmlessly. This article will go over the pros and cons of insulating a cavity wall, as well as the primary function that a cavity wall was designed to perform, and finally how an insulated cavity wall will work for your home.

How far apart should I drill holes for cavity walls?

The company that you hire will need to determine where the cavity walls are located. Then, they will have to drill several one and a half-inch full holes about 3 feet apart. Then, the insulation material will be injected into the cavity through the holes.

What is an unfilled cavity space?

Having an Unfilled Cavity Space. First and foremost, the cavity space between the two skins of the wall needs to be empty. Sometimes, in older homes, wood may have been placed in between the area as a spacer, reinforcement, or as prior-insulation.

Why is it important to insulate the exterior of a house?

By insulating the exterior cavity you gain the added benefit of reducing thermal bridging by blocking the outside elements before they make their way into the interior walls. This is both due to the location (external) as well as the advantage of creating a continuous barrier.

Why is there mold in my cavity wall?

This is because the insulation will restrict the moisture from passing through the wall. Water can pass or go through the outer wall because it is porous. With the cavity wall that is insulated, water will be trapped in between and will just run down ...

What are cavity walls made of?

These walls are made of two parts that have a gap or are separated by a hollow space that needs insulation and the wall materials are commonly bricks and concrete blocks.

Why do beads need adhesive?

To keep the beads from escaping, adhesive is used to pump these materials in. These materials are preferred than wool material because of its many advantages. Apart from size that makes beads easier to inject even in the narrowest cavities, they can easily fit in the cavity walls because they spread out.

What is the advantage of cavity wall insulation?

Heat Loss Reduction. Another important advantage of cavity wall insulation is minimizing the amount of heat that escapes from the walls during winter months through convection, one of the three way that heat travels. By installing cavity wall insulation, it is like putting a lid on a cup of hot coffee.

Why does coffee get colder?

By doing so, it will take longer for the coffee to get cold because heat is trapped. This is also what this type of insulation does to the heat. It seals in the small amount of air that is between the walls made from masonry materials. 3. Cheaper in Expense.

Can you retrofit a house with cavity walls?

While newer houses can have this type of walls, homeowners with houses that do not have cavity walls will have to retrofit their homes. Apart from additional expense, it will also take time to do so. And if the owner has no budget for this or the house is too old to fix, cavity wall insulation is not possible.

Why are drill holes small?

Additionally, with the smaller size, drill holes will also be small so they will not damage the walls and will be easy to cover as well. 2. Heat Loss Reduction.

Why is cavity wall insulation important?

The primary purpose of cavity wall insulation is to prevent heat loss and moisture build-up.

What is a cavity wall?

Cavity walls consist of two layers of brickwork that are separated by a gap or cavity of air. Most houses these days are built with this type of wall structure as cavity walls provide much better thermal qualities than their solid wall counterparts.

What is cavity wall insulation?

Cavity wall insulation, as it is typically known, is the process of blowing insulating material into the cavity between your inner and outer brickwork. This is achieved by drilling a series of tactfully placed holes into the outside of your home which then access the cavity space.

What is protective wall coating?

The protective wall coating resists water droplets, as well as prevents dirt and debris from building up on your walls. Typically, this is a very straight-forward application process that can be achieved with minimal disruption to your home.

Is moisture bad for a cavity wall?

The Potential Drawbacks of Cavity Wall Insulation. Moisture is often a big problem when it comes to cavity wall insulation pros and cons. In fact, some properties actually suffer as a result of installing cavity wall insulation, rather than receive any benefits.

Does moisture build up on walls?

The protective wall coating resists water droplets, as well as prevents dirt and de bris from building up on your walls ensuring the outside of your home remains spick and span!

1. It Can Reduce your Energy Bills

On average CWI can save you between £100-£200 a year on your heating bill! So, for most people it will of paid for itself in just two years.

2. Keeps your Home Warmer

Cavity wall insulation, stops heat escaping from your home through the cavity walls, meaning your heating is more efficient and a more consistent level of warmth is kept.

3. Quick and Easy to Install

When installing CWI very little disruption is made to the household because all the work is done from the outside to the external walls. Small holes are drilled all over the wall and then an insulative material is injected through these holes into the cavity.

4. Cheapest Energy Saving Measures You Can Install

CWI cannot be installed yourself; you will need a professional however its relatively inexpensive, a flat or mid-terrace house costs between £300-£400 and a detached house is about £700 on average. However, its definitely worth the initial cost when you consider its effectiveness and the potential savings.

Moisture Penetrating the Cavity

In areas exposed to wind driven rain, usually on the coast. Then rain water can make its way through the external brickwork and into the cavity and is soaked up by the insulation material, at this point the insulations ability to keep your home warm will reduce massively.

Voids in the Cavity

As mentioned before about dodgy installers, it is known that some cut corners. Poor and rushed installation can lead to ‘voids’ in the wall where the insulative material hasn’t covered, meaning part of the wall is insulated and other spots are not.

Condensation

Interstitial condensation is when condensation occurs in a cavity, in this case a wall cavity. It occurs on the external brickwork side of the cavity, when the internal walls become warmer than the outside, repelling the condensation away from the inner wall and condensing on the external brickwork instead.

Why do we need cavity walls?

The idea of cavity walls was to create an air break between the two parts of the wall, to prevent damp forming along the interior of the wall of the home. When the weather is wet the damp will run down the exterior part of the wall and then dry out, preventing damp from getting into the interior of the home.

How many inches of insulation does a brick house need?

Most brick homes built since 1970 in the UK, and certainly many built between 1930 and 1970, have cavity walls. Most of these homes have a cavity of about 2 inches, which is considered the ideal specifications for cavity wall insulation.

Does cavity wall insulation help with damp?

It has now been established that cavity wall insulation, by creating a bridge between the two walls, facilitates the ingress of damp into the property, where the insulation material has lost its damp proofing properties, or wasn’t particularly damp proof in the first place.

Is mineral wool insulation waterproof?

The government believes it’s beneficial; in fact, together with energy companies, they now sponsor the installation of cavity wall insulation. Mineral wool fibre has proven to be less waterproof than previously thought, and is believed to degrade under damp conditions.

Does spray foam insulation work?

The use of more effective spray foam insulation has become more widespread; this foam when applied naturally expands to ensure that there are no cold spots or gaps left in the wall.

Is brick a porous material?

Bricks and natural stone are porous building materials, and allow cold and damp to cross over into the interior of a house. However, with the application of Home Logic External Wall Insulation, homes remain warm in Winter and cool in Summer and thus far more conducive to comfort. Result!

What are the benefits of cavity wall insulation?

Well-insulated external walls help to create an efficient building envelope. This means less heat escapes from inside your home. Your central heating system won’t have to work as hard to achieve comfortable temperatures, saving energy and money on utility bills, and reducing your carbon footprint.

Who supplies cavity wall insulation?

Retrofitting cavity wall insulation is not a DIY job; and badly fitted CWI by a cowboy builder could cost you a serious amount of money to fix. It’s important to employ a qualified installer using an approved insulating system.

Tips for installing cavity wall insulation

It can be tricky to tell if your home has cavity walls, but there are clues to look for. Cavity wall bricks tend to be laid in an even pattern with only the long edge exposed, whereas solid walls often have a mixed pattern of long and short brick ends.

What maintenance is required for cavity wall insulation?

CWI is a fit-and-forget option, so you won’t need to maintain the insulation itself. Improving ventilation and staying on top of general property upkeep will ensure your energy efficient home continues to perform as expected.

How does cavity wall insulation affect my EPC rating?

An Energy Performance Certificate (EPC) provides information about a property’s energy use. The EPC shows how much heating, hot water and lighting is likely to cost per year, as well as probable carbon dioxide emissions. Every home built, sold or rented must have an EPC, which rates the house from band A (most efficient) through to G (inefficient).

Do new builds come with cavity wall insulation as standard?

Every newly built house – whether it’s constructed with cavity walls or another method – must meet or exceed the Building Regulations for energy efficiency under Approved Document L.

Should I add cavity wall insulation to my extension? And which is best?

Most extensions are built with cavity walling. Under the Building Regulations, they must be insulated to modern standards. Rigid foam boards and mineral wool batts are your main options, and the best choice will depend on your project goals.