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You are here: Home / Archives for loft insulation

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Loft insulation – keeping you toasty and saving you money

Insulation saves heat and heat costs money. So, it’s a simple fact that if you’re saving heat, you’re saving money. The more you insulate the more heat you save and the less money you spend.  There is no better time than the present to check your existing insulation and make sure your loft is properly insulated for the autumn and winter ahead.

The more you insulate the more you save

If the existing insulation is in good condition and measures 270mm or more in depth, then you shouldn’t need to install more insulation.  However, if your loft is full of old insulation which has slumped and degraded, then the last thing you want to do is install more of the same.  If you do, someday you’ll return, look at the same scene and repeat the same exercise. Instead, use something that won’t slump or degrade and buy something that lasts. A natural fibre insulation which is thermally bonded with recycled polyester such as Thermafleece British Sheep’s Wool Insulation will ensure the insulation retains its loft and once you insulate, you won’t have to do it again.

There are also many other benefits of installing a natural fibre insulation: As well as keeping in heat, natural fibre insulations will help manage summer heat gain; help with moisture and humidity levels; reduce noise and improve sound quality. They are none itch, safe to install and can improve indoor air quality, sustainability, health and well-being inside your home.

The More Insulation the Better

The more insulation you can install the better, but typically you should install a natural fibre insulation to a depth of 240mm. It is not always necessary to remove your existing insulation. As long as it is in fairly good condition and there is no signs of water damage then you can top up with a good quality natural fibre or recycled polyester insulation.

In most lofts, it’s easy to install a deep layer of insulation. If you decide to board part of your loft you can use loft legs to raise the level of the boarding. This will still allow you to install a deep layer of insulation.

Remember that around 5% of heat is lost through your loft hatch, so it should also be insulated.

In a new property with a well-ventilated loft, a recycled polyester insulation such as SupaSoft Insulation will be very effective. SupaSoft insulation is a great way to use recycled single use plastics. It’s also safe to handle and itch free.

For an older property or if loft ventilation is limited,  use a natural fibre insulation such as Thermafleece CosyWool Roll. As well as being safe, sustainable and healthy, natural fibres can help regulate humidity levels. They do this by absorbing moisture and holding it in a safe form. It’s then released it as air around it becomes less humid.

In a nutshell

In a nutshell:  Insulation does much more than prevent heat loss so give this some thought when you decide what’s right for you. Choose a good quality  insulation which will last the lifetime of your building. You’ll never have to do it again and remember that over its life, insulating is never a costly investment.

Filed Under: Blog Tagged With: British sheeps wool insulation, insulate your loft, loft insulation, thermafleece

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How much insulation do I need in my loft?

How do I measure and calculate how much insulation I need in my loft?

It is important to take the time to work out how much insulation you need to ensure you get the best fit and also, so you don’t over or under order.  Planning the installation is an important part of the job and correctly laid insulation significantly improves thermal performance.

When insulating using Thermafleece we recommend you should install to a minimum depth of 240/250mm and ideally 300mm particularly for new build properties.  You will need to install one layer between the ceiling joists and one or more layers above the level of the joists.  The insulation above the joists is cross-laid over the joist meaning it runs perpendicular to the direction of the joist. The joists are the horizontal timbers that support the ceiling below the loft.  These are often confused with rafters which are the angled timbers that support the roof.

There are 3 simple steps to measuring for your loft

Step 1. Measure the total loft space. 

This will provide a total square metre requirement.  Simply multiply the length (in metres) by the width (in metres) of the loft to calculate the area in sq.m.  For the layer of insulation that is fitted between joists, deduct 10% of the loft area to account for displacement of the joists.  For insulation layers that sit above the level of the joists take the full loft area.  If you can’t access the loft or to give yourself a sense check, simply measure the outside of the building for dimensions.

Step 2.  Measure the space between your joists.

Measure the width between joist ensuring the tape measure runs perpendicular to the joist.  Repeat this to determine the minimum and maximum spacing between joists.  This will allow you to determine the  width of insulation required to fit between joists.  Often and especially in older properties the width does vary but several width options are available, and Thermafleece is a quilt material which is forgiving against the timbers.  Thermafleece is available in a variety of widths.  This is only required for the layer of insulation fitted between joists, layers cross-laid over joists do not need to fit between anything so we generally recommended our widest widths for this.

Step 3. Measure the depth of the joists.

Typically, if your joists are 100 mm thick, we would recommend you full fill the joists with  100 mm thick.   To increase the thickness and eliminate heat loss, we would recommend 100 between and at least 140 mm over the joist. This generally means that you put one layer between the joists then other layers running above the joists across the direction of the joist.

Example Using Thermafleece CosyWool Roll.
Space between joists is 350mm.  370mm insulation width required.

Loft Area – 9 metres x 7 metres  = total area 63m2

Joist depth – 100mm

Recommended Insulation depth is 240mm

Between the joists:
100mm thick x 370mm wide. 3 rolls in a pack and total m2 of one pack is 7.22m2

Area required is 63 sq.m less 10% = 56.7 sq.m

56.7 square metres ÷ 7.22 square metres per pack  = **7.85 packs

You would need to order 8 packs of 100 x 370 which will provide you with 57.8 sq.m to go between the joists.

Cross-laid over the joists *
140mm deep x 570 wide 2 rolls in a pack and total m2 of one pack is 5.24m2

63 square metres ÷ 5.24 square metres per pack  = ** 12.02  packs

You would need to order 12 packs  of the 140 mm x  570mm which will provide you with 62.88 square metres to go crossways over the joists.

*Remember: Layers cross-laid over joists don’t need to fit between anything so we generally recommended our widest widths for this 

**We don’t split packs so depending on how generous your measurements are, round up or down

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Find out more:

Further information is available in our Help and Advice Section: https://naturalinsulations.co.uk/help-advice/

Thermafleece British Sheeps Wool:  https://www.thermafleece.com/

Featured Image is from the Cold Roof Application Notes, one of a series available in the Help and Advice Section

Filed Under: Blog Tagged With: how much insulation do I need?, insulation depth, loft insulation, measuring loft for insulation

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