Go back
Spray Foam Insulation

Hemp Fibre Insulation Boards: Are They Good Value For Money?

hemp fibre insulation boards

We all know that it is a great idea to properly insulate our homes, but did you know that there are almost as many ways to do it as there are materials available? 

These days, you can choose from fibreglass wool, mineral wool, sheep’s wool, straw bales, spray foam and even hemp fibre insulation boards. When it comes to the last of these, is it good value for money and why might it be better to choose another option?

The Energy Saving Trust points out that one quarter of the heat we have in our home is lost through the roof and a significant portion makes its way out through the walls. 

They say that a detached home can expect to reduce energy bills by more than £200 by simply adding loft insulation to the required depth of 270mm, while wall cavity insulation can reduce bills by even more than this. 

So it is easy to see why insulation has been a huge government campaign in recent years - the savings can be huge and the work done is relatively easy and cost effective. 

But what about hemp fibre insulation boards? Will they offer these levels of savings? It’s time to find out…

hemp fibre insulation boards

Most insulation is made using the waste straw that is left over from the seed harvest, and, therefore, the product is a great use of what would normally be thrown away or left to rot

What Are Hemp Fibre Insulation Boards And Why Are They Popular?

Hemp is a fast growing crop that has been used for hundreds of years for things like rope making, sails, clothing and as an insulator. 

It has always been prized for its durability and the fact it is resistant to mildew and damp. In fact, the material has the ability to regulate thermal performance, while still offering structural rigidity - especially when compressed into boards.

As a truly sustainable product, hemp can be grown consistently throughout the year and does not have a long growing cycle. 

Most insulation is made using the waste straw that is left over from the seed harvest, and, therefore, the product is a great use of what would normally be thrown away or left to rot.

It also needs very little water to grow well and does not need herbicides or pesticides. Many farmers use it as a way to improve their soil by growing it as a way to give the soil a “break” from normal food crops. 

Finally, the production of hemp insulation takes very little energy and leaves a small carbon footprint. 

With the insulation boards having at least 90% hemp, the use of other products is limited to a few binders, making it biodegradable and even useful as a material in fires to provide more energy.

hemp fibre insulation boards

Hemp insulation will generally cost between £15 and £20 per square metre and is therefore more expensive than some other standard insulation types. This is often the case when it comes to sustainable materials

Hemp Insulation Boards: An Overview

●    As an insulator, hemp fibre insulation boards can absorb up to 20% of their weight in moisture and still retain the same level of thermal performance. This moisture will then naturally dry out over time, preventing damage from sudden condensation. This compares to mineral wool insulation which will need replacing if it becomes wet.
●    The thermal performance of hemp insulation is thought to be around 0.039 W/mK with conductivity levels. This makes it an excellent insulator in most circumstances.
●    The rigidity of the boards makes hemp a good option for use in walls and to line lofts. Unlike other, similar materials, the boards tend not to sag over time.
●    Hemp fibre insulation boards meet the Euro Class E fire rating standard and are made using non-toxic materials that will not cause a fire or make it worse.
●    The product can usually be installed by a DIYer relatively easily.

How Much Do Hemp Fibre Insulation Boards Cost?

When comparing your insulation options, the cost is going to be the factor that might sway your opinion. 

Hemp insulation will generally cost between £15 and £20 per square metre and is therefore more expensive than some other standard insulation types. This is often the case when it comes to sustainable materials.

hemp fibre insulation boards

The shelf life of hemp boards is relatively short compared to other materials, and, as a result, you will have to remove and replace boards as they start to fail

What Are The Drawbacks Of Using Hemp Insulation Boards?

As you can see above, there are so many reasons why hemp makes for a good sustainable choice when it comes to insulation. 

But it is not all good and the choice of a good insulation has to come down to all factors working together. Some of the reasons why you might consider an alternative are:

●    Hemp has to be combined with a binder to turn it into boards and the choice of binder can sometimes be toxic or unsuitable for damp conditions.
●    The fact hemp absorbs moisture can, over time, lead to issues with condensation and a loss of thermal ability.
●    The boards offer structural integrity to a wall, but are not in any way strong enough to support floors or ceilings.
●    The boards have to be cut to fit between rafters and into smaller spaces. It is very difficult to ensure total coverage, and there will often be gaps around the edges.
●    The shelf life of hemp fibre insulation boards is relatively short compared to other materials, and, as a result, you will have to remove and replace boards as they start to fail.

hemp fibre insulation boards

As you can see, spray foam insulation makes for a good option for your home and when compared to hemp fibre insulation boards, it is a far more flexible product. Hemp is sustainable and ecological, but it will not last as long, nor offer the same economic savings

Spray Foam Insulation: The Ultimate Flexible Friend

While hemp is a good product if you are looking for an ecological insulation option, spray foam insulation might be a better performer and a more flexible choice for your home in the long run. 

Spray foam insulation is a mixture of chemicals that form a foam that expands to be many times its liquid form. 

Once sprayed onto your walls and rafters, it is entirely safe and non-toxic and will not release any chemicals into the air. It also offers excellent thermal properties and is considered to be the best insulator for its size.

While you may need 270mm of mineral wool insulation to achieve the best possible savings, spray foam insulation offers the same thermal improvement with only 100mm of product. 

This means that you don’t lose head height in your loft, and you can easily fit the foam into the spaces within your walls and between your rafters.

Spray foam is a durable product that is known to last upwards of 50 years. In fact, as it has only been used as an insulator for the last few years in the UK, we don’t yet know how long it will last - but the signs look very impressive based on studies from the US. 

Once you have this foam installed, you probably won’t need to replace it while you are living in your home.

Insulation must be kept dry to work well - even if it absorbs some moisture. Spray foam is entirely waterproof and will not absorb any moisture. This means that the product never loses its integrity and will continue to do the job it was intended for. 

Despite this, spray foam is a breathable product that will allow wetness to dry out and will help to prevent condensation.

As you can see, spray foam insulation makes for a good option for your home and when compared to hemp boards, it is a far more flexible product. Hemp is sustainable and ecological, but it will not last as long, nor offer the same economic savings. 

Have a chat to us about what might work best for your home - especially if you want an insulation that will give you the money savings you need. Simply call 0800 1700 636, or click the button below to get started today!