Can You Put New Insulation Over Old Insulation?

Published on August 29, 2019

If you need to enhance the existing insulation in your home, you may be wondering about installing new insulation over old insulation. The fact is, there’s probably some type of insulation in your exterior walls and throughout your attic.

The important thing is to determine the condition of your existing insulation and then determine whether complete removal is necessary, or if a so-called “top up” would be an effective option. Here, a professional assessment would be the best.

In general, it’s possible to “top up” existing home insulation, as long as the materials are in good condition, and without any deterioration. When there is a problem with existing insulation, the cause and scope of the problem needs to be addressed.

Should I remove old loft insulation before laying down new? 

In the majority of instances, it’s much better to remove old insulation materials before installing any new material. This will allow for a fresh start, and the best possible results. It’s definitely possible to install new insulation over old insulation, but the best outcome is achieved when the installation space is properly sealed and well ventilated.

At EcoComfort, we typically recommend a removal and retrofit approach when it comes to home insulation improvements. We start with a full inspection of the space, whether in the attic or the basement. In this way, we discover insulation material that is damaged or inadequate, and we then recommend necessary repairs and retrofits to suit.

With any insulation project, we incorporate air sealing and air ventilation to ensure the best performance for the installed insulation. Air sealing rids the space of any air leaks that would compromise insulation performance. As well, proper air ventilation improves the overall energy efficiency and indoor comfort of your home, season to season.

Can you over insulate an attic?

With home energy prices increasing, many homeowners are considering improvements to their home insulation, particularly in the attic. The big question is whether to add new insulation over old insulation or to start fresh by removing all of the old insulation.

With home insulation, adding more insulation to existing insulation is not always the best option. This is particularly true in an attic space because over-insulating can cause other problems. With a professional on hand, the installation always suits the need.

In a space like the attic, too much insulation can compromise ventilation, and therefore trap undesirable air moisture. Over time, too much moisture can build up, and there is added potential for mold to develop. This will directly affect your indoor air quality.

How often should attic insulation be changed?

The most obvious sign of under-performing insulation is when heating/cooling bills start to skyrocket. Typically, home insulation starts to underperform after about 15 years. Indeed, in an older home, attic insulation may be the same insulation from when the house was originally built.

Depending on the signs and symptoms, your attic insulation may need to be improved even before the 15-year mark. You may notice air drafts – you may notice that the HVAC is overworking (summer and winter) – or you may notice rooms that are overly cool or hot. All are signals for action.

Do I need to remove old blown in insulation?

With home insulation, regardless of the product, it’s best for a professional contractor to determine the quality and performance level of the existing insulation. This is done with an in-depth inspection of the space and a proper assessment of overall energy efficiency.

When an attic space is insulated with blown in materials, for example, it’s important to determine whether complete removal is necessary. It’s also important to consider the various options for re-installation. The reasons for removing insulation are often varied.

To be sure, a professional contractor should remove old blown-in insulation. This should not be a do-it-yourself project – the work is challenging and can often be dangerous. The removal proves requires special equipment, proper safety gear, and a level of expertise.

How does attic insulation work?

Whether you plan to install brand new attic insulation, or install new insulation over old insulation, the dynamics are the same. The idea is to create a thermally resistant barrier that will prevent airflow (heating and cooling) from moving in and out of your home.

Simply put, attic insulation blocks outdoor heat from entering your home in summer and blocks indoor heat from escaping during winter. With good insulation, the results are a evident – a cooler home in summer; a warmer home in winter, and lower energy bills.

With high quality attic insulation, the cost of retrofitting and reinstallation is often “paid down” with the significant annual energy savings. Depending on the extent of work, it may take a few years to pay down, but the savings year after year are very worthwhile.

When attic insulation is enhanced, both energy efficiency and home comfort are equally enhanced. The HVAC system works better when heating or cooling. Indoor air quality is much improved. And air moisture throughout the entire home is much better controlled.

Choosing Blown In Cellulose Insulation or Fibreglass Insulation with EcoComfort

Whether you’re installing new insulation or adding new insulation over old insulation,
EcoComfort recommends either blown-in cellulose or blown-in fibreglass insulation. While each product has pros and cons, customers have better outcomes with cellulose.

Blown-in Cellulose Insulation

An excellent option for the attic space, because there are limited access points. Cellulose is considered eco-friendly since it’s produced with various recycled materials. When it’s blown in, this product is fast and and clean to install, particularly in hard-to-reach areas.

As for thermal performance, blown-in cellulose compares very favourably with other types of insulation, and is quite effective in enhancing the R-Value of existing insulation. Cellulose will also reduce noise, resist mold, and is pre-treated to be fire retardant.

Blown-in Fibreglass Insulation

Similar to the cellulose material, this product is made of glass fibres that are fabricated into a “fluffy” composition. Blown-in fibreglass is an excellent option for “topping up” new insulation over old insulation – mainly because the installed product doesn’t settle.

Fibreglass blown-in insulation has comparable R-Values to cellulose, and performs very well in fire tests. It’s also very resistant to mold growth because it doesn’t provide a food source. With a professional install, airborne dust is easily controlled and reduced.

At EcoComfort, we’ll help you to make the best product and installation decisions. We’ll recommend whether insulation removal is required, or if we can effectively add new insulation over old insulation.

Find out more about our many services by calling 416-639-3154 or visiting our company website at.