Causes are:. Cold bridging also has the potential to cause a damp problem. Where previously either no condensation occurred, or it occurred over a large area and evaporated fairly quickly without incident, after insulation condensation can concentrate onto relatively small cold bridges and cause mould or fabric damage. This isn't normally a problem, but can be. Any gaps that admit wind allow heat loss to simply bypass the insulation in that area.
Thus good insulation requires plugging any gaps. Depending on the situation this can be done with loosefill insulation, injected expanding foam, pressed in foam strip, or for opening doors and windows, brush strip or foam strip.
Wind can blow through some insulation types, eg fibreglass loft roll, much reducing their insulation value. These types are not well suited to use in windy positions. Some unpopular insulating materials don't have a known insulation value, they've not been tested. If you want to use nut shells for example, you can if you wish set up an experiment to determine their insulation value. Thick high insulation value material is added around the 4 sides of the stack. The stack bottom is left uninsulated.
The stack is left with the heat source on for hours to stabilise, then the 3 temperatures are read. The insulation value of the unknown layer is determined from the ratio of thermal resistance insulation values. Where the resistances are R1 and R Most accurate results are obtained when the insulation values of the 2 layers are in the same ballpark, and top plate temp is high.
For accuracy, avoid using results where the middle interface temp is close to top or bottom plate temp, or the top plate temp is low. Self testing is only sufficient for applications where BR approval is not required.
To obtain BCO approval with non-standard materials requires the test results and building insulation design to be signed off by an engineer. Other aspects of insulation also need to be considered in this. With 69, house fires in , the performance of insulation in a fire affects loss of property and life. There are 3 main fire performance possibilities:.
Cladding applied for external wall insulation has been implicated in some major fires including Grenfell Tower June Below we take a look at performances exhibited by a range of common and increasingly common construction insulation materials.
Insulation materials, particularly where 'green' specification is concerned, divide into so-called 'natural' materials and 'man-made' materials. When considering how to specify an insulation material in terms of environmental impact, it is often the case that the 'natural' material is the most beneficial in terms of environmental attributes. However, in some cases, the inherent efficiencies of man-made materials can be included into the environmental equation to provide a wider environmental benefit eg where space for insulation is at a premium such as in retrofit.
Thermal conductivity measures the ease with which heat can travel through a material by conduction. Conduction is the main form of heat transfer through insulation read more about heat transfer.
The lower the figure, the better the performance. Together these parameters form the thermal resistance of the construction.
A construction layer with a high Thermal Resistance, is a good insulator; one with a low Thermal Resistance is a bad insulator. The Specific Heat Capacity of a material is the amount of heat needed to raise the temperature of 1kg of the material by 1K or by 1 o C. A good insulator has a higher Specific Heat Capacity because it takes time to absorb more heat before it actually heats up temperature rising to transfer the heat.
A high density material maximises the overall weight and is an aspect of 'low' thermal diffusivity and 'high' thermal mass. Thermal Diffusivity measures the ability of a material to conduct thermal energy relative to its ability to store thermal energy.
For example metals transmit thermal energy rapidly cold to touch whereas wood is a slow transmitters. Insulators have low Thermal Diffusivity. Though not an aspect of the thermal performance of an insulation material, Embodied Carbon is a key concept in balancing the global warming gases in producing the material with the that conserved throughout the lifetime of the insulation.
Embodied Carbon is usually considered as the amount of gases released from usually fossil fuels and used to produce energy expended between the extraction of raw material, via the manufacturing process to the factory gates. In reality, of course, it goes much further than that including transportation to site, the energy used in installation through to demolition and disposal. The science of embodied carbon is still evolving - consequently, firm and reliable data is difficult to obtain.
Look out for EPDs which detail the inputs and outputs of the industrial processes. Read more It is measured by the time rate of vapour transmission through a unit area of flat material of unit thickness induced by a unit vapour pressure difference between two specific surfaces,under specified temperature and humidity conditions.
Often referred to, erroneously, as 'Breathing construction', walls and roofs so termed are characterised by their capacity to transfer water vapour from the inside to the outside of the building - so reducing the risk of condensation. Gases possess poor thermal conduction properties compared to liquids and solids, and so makes a good insulation material if they can be trapped.
Be sure you're wearing your safety equipment, as the itchy fibers of the batting can cause respiratory problems and eye irritation without a barrier in place.
Only unroll your batting once you're in the attic, to avoid letting fibers contaminate the rest of your house. Lay the first layer. Unroll the batting blanket into the space between two joists. If the blanket isn't wide enough to match the width of the space between joists, unroll it from joist to joist instead, and lay more short lengths next to each other until the full length between the two joists is packed. Press and tuck the edges of each part of the blanket, to make sure they fit snugly and that there are no gaps between them.
Cut a hole in the insulation wherever there is electrical wiring. Pull the wiring up through the hole and rest it on top of the insulation, so that the heat it generates will dissipate upward rather than being trapped under the insulation.
Check depth and repeat if necessary. If you're fairly sure that one layer of insulation isn't enough to reach an R rating, you can add another layer. Lay this layer at right angles to the first layer, to reduce leaks and gaps.
Be sure to cut holes for electrical wiring and pull it through the second layer, as well. Remember, the rule of thumb is that if your insulation is at about the same level as the tops of your joists, the insulation should be adequate. However, if you want to be sure, you can compare the R-ratings per level of insulation to the R-rating you're trying to achieve, and make a more educated guess based on that.
Method 3. Estimate the amount of fill you'll need. Generally speaking, without any preexisting insulation in place, it takes 10—12 inches Find the rough surface area of the base of your attic and ask the seller how many pounds of fill will be required to fill that area to 11 inches Rent a blowing machine.
Many home improvement stores offer blowing machine rentals for the DIY-minded. Remember, machine-blown fill insulation will be more effective than hand-filled, so unless you want inferior insulation from your material, rent a blowing machine when you buy your insulation.
Baffle your vents. Soffit vents will need to be baffled protected from getting clogged with fill insulation before you work. Add one rafter vent baffle to each soffit vent. Set up and use the blowing machine. Carefully follow the instructions that come with your machine to set it up and begin blowing insulation with it. Blow your insulation in evenly and smoothly.
Stop every few minutes to check the depth of the insulation and be sure it's more or less even. Keep going until the proper depth of insulation has been reached. See Step 3 of Method 1 of the article. Upload file Recent changes Latest files Random file Contact us.
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