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Insulation Explained

A guide to how insulation can save you time and money, keeping your home warm and peaceful.

A poorly insulated home can cost you a lot of money and energy. This is because you will naturally need to use heating and cooling devices (such as radiators and fans) to get the right temperature that good insulation would be able to help with. Therefore, insulating a building can greatly reduce your energy consumption. 

When we talk about insulation, it’s important to remember that whilst thermal properties are important, there are also other benefits that can be gained from insulation: 

  • Acoustic features stop noise from travelling between rooms and adjoining properties 
  • Fire Resistance helps to slow down the spread of fire 

The key to choosing the right insulation is to determine what the overall needs for each area are: 

Roof and Rafters 

It’s common knowledge that warm heat rises and according to the Energy Saving Trust, “a quarter of heat is lost through the roof. Adding insulation to the roof and rafter is a long-term solution that will help to save you money and prevent wasted heat.    

The type of insulation you choose will depend on what you use your roof space for:    

  • Room. If you use your loft as a bedroom or living space, you want to ensure that you have fully insulated all walls and the ceiling.    
  • Storage. If you want to store the Christmas decorations and empty suitcases in your loft, you will need to raise the level of the floor and add mineral wool so that you can lay floorboards over the joists.    

Bear in mind that if your loft has problems with damp or condensation, insulation could cause problems. Unless your loft is used as a living space, insulation is designed to create a cool space, and as such this will make damp worsen. The easiest way to remedy this is to ensure you have plenty of ventilation.  

Which Insulation for Roofing?    

The Thermal Insulation Roll is designed specifically for use in lofts; helping to boost energy efficiency by reducing the heat transfer through the roof.  Another option is PIR Boards which can be used if you have a void that needs filling. 

Roof Access Points    

If you have a trap door leading into roof space that isn’t converted into a room, we recommend keeping it closed to prevent the heat from the main areas of your home being drawn into the wasted space. Modern loft access panels are typically insulated, so you shouldn’t need to do anything extra. 

However, if you do experience draughts from your hatch, adding a barrier such as a foam strip should help. 

If you use insulation such as the Rockwool Thermal Roll, it is a good idea to insulate the loft hatch cover with the same product, to ensure continuity. 


The Energy Saving Trust says that “About a third of all heat lost in an uninsulated home escapes through the walls.” If your home was built after 1990, it is highly likely that your walls are already insulated, however anything older, they might not. 

Knowing how to tackle wall insulation will depend on the type of wall you have. If you’re not sure, here are a couple of tips:    

A cavity wall:    

  • Will have been built post-1920    
  • If you look at the bricks around the exterior of your property, they will have been positioned in an alternating pattern with the length of every brick facing outwards    
  • Cavity Walls have two leaves and insulation can be injected into the middle; however, this is not a job you will be able to do yourself.   

A solid wall:    

  • Been built pre-1920    
  • The bricks will be in a similar alternating pattern; however, every other row will have the end of the brick facing outwards    
  • Solid Walls can be insulated from either the interior or exterior.    

Which insulation material for Walls?    

If you have walls that are controlled by building specifications, Glass Wool (manufactured from recycled glass) is a good choice as it is high-density but still fits into a small space. This means that it will meet all the necessary regulations. Fibreglass is also ideal for partition walls and external timber frame walls.    

PIR Boards such as Eco Cavity and Eco Liner are designed specifically to be fitted with the specific dimension of bricks and block, making them ideal for use a wall insulator.    

If you are looking to reduce the sound levels passing between rooms in your property, or adjoining properties, the Sound Insulation Slab is a good choice. It is suitable for both internal and separating walls.   


Windows are notorious for being draughty and if you live on a busy street, they can also be the main route for sound to travel into your home. The obvious solution is to replace them for double glazed ones. However, when that isn’t an option for you, a few ideas you might consider include:    

  • Installing thick curtains and closing them as soon as it gets dark.  
  • If you can find a pair of curtains that has a thermal lining, this will help keep a room warm.    
  • Pushing the curtains behind radiators, so that heat isn’t directed to your windows, can be a big help. However, ensure that you open them during the day so that the sun can heat your home naturally.    
  • It is also possible to purchase soundproof curtains that might not completely block noise, but they can often help to reduce it. 
  • Use foam strips around the edge of the glass    


Every so often, you may notice that your radiators aren’t heating up like they used to, or you can feel cold spots when you touch them with your hand. This is typically caused by bubbles of air that have become trapped in your system and the best way to fix this is by bleeding your radiators. 

As suggested above, ensure curtains are placed behind them and try not to block radiators with pieces of furniture unless necessary. A sofa sat in front is just going to absorb the heat, so moving it will allow the heat to spread out around the room.    

Consider placing a shelf above the radiator that encourages the heat to divert out rather than heading straight upwards, above your head.    

For pipework connected to your radiators, consider using pipe insulation materials, such as pipe lagging to prevent them from freezing in the winter and/or from rattling.    


External doors are rife with areas that could potentially allow draughts to pass through:    

  • Keyholes. A cover can be added that moves aside when you need to insert a key.   
  • Letterboxes. Attaching a brush to your letterbox will not only reduce chills, but it can also help to add privacy.    
  • Gaps around the edges. Draught excluders can be used, or a weather bar fitted, to the bottom of the outer side of your door that will help to prevent snow and rain from getting into your home.    

Internal doors are a little easier. Try to keep doors closed, especially if they lead to a cold space, for example, a spare room or the hallway.    

If there is a gap at the bottom of the door, a “sausage dog” type draught excluder can be incredibly helpful. 

Click here to view the full range of insulation products that we offer and tackle all those insulation problems that are hitting your bank balance or just a general nuisance. 

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Kat Musselwhite – Howarth Blogger.