Since 2003, current building regulations recommend a depth of at least 270mm (mineral or
We'd recommend everything in moderation. While some people argue that an over-insulated house could cause damp, mould and other issues. Typically, upping your loft insulation from 270 mm to 400 mm isn't really going to make a big difference, and so it's probably worth sticking with the lesser amount.
What's the best loft insulation thickness? The UK government recommend a minimum insulation thickness of 270mm although we tell people that 100mm should be the absolute minimum.
The 50mm thickness is a common standard for loft insulation and provides a good level of thermal resistance to prevent heat from escaping through the roof. By installing this type of insulation, homeowners can improve the energy efficiency of their homes, reduce their carbon footprint, and save money on heating bills.
The higher the R-Value, the better the thermal performance of the insulation. The recommended level for most attics is to insulate to R-38 or about 10 to 14 inches, depending on insulation type.
Can Loft Insulation Be Too Thick? Although it can be tempting to believe more is always better, exceeding recommended loft insulation thicknesses can actually have a number of negative consequences. The most common of these is poor ventilation, which can lead to issues such as damp, condensation, and mould.
While loft insulation is an effective way to improve energy efficiency and reduce heating costs, over-insulating can lead to several potential issues. Firstly, over-insulation can lead to poor ventilation in the attic, which can cause moisture buildup and increase the risk of mould growth.
Excessively thick insulation can block most ventilation sources, reducing air quality and restricting air exchange within the loft. It can also negatively impact air circulation, which causes respiratory problems and other related health issues.
25mm Mannok PIR Insulation Board is an excellent choice for anyone looking for a high-performance insulation solution that provides superior thermal efficiency. It is ideal for use in any construction project, such as commercial and residential, in wall applications as well as roofing and flooring applications.
Don't block any vents such as soffit vents with insulation. Don't squash the insulation as this can reduce its thermal performance by over 50%. Don't install loft boards directly to joists or trusses.
In 2024, UK loft insulation rules require a minimum insulation thickness of 270mm to meet a U-value of 0.16 W/m²K, along with proper ventilation and fire safety compliance.
It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers.
100mm Insulation: The Ultimate Thermal Efficiency
With double the thickness of 50mm insulation and quadruple the thickness of 25mm insulation, it provides an excellent barrier against heat transfer.
It is recommended to have at least 270mm of loft insulation material in place, especially when using insulation materials such as mineral wool or sheep wool. Increasing this thickness to 300mm may provide slightly better insulation, but 270mm is considered more than adequate for the job.
Fibreglass insulation is not illegal in the UK and is quite common in loft upgrades, however, it's important to handle it carefully to avoid health risks.
You'll need to start laying with a minimum gap of 25mm between the eaves and the insulation to ensure a suitable air gap. Maintain this gap along two opposite sides of the loft.
Current government recommendations are for loft insulation thickness to achieve a depth of 270mm, but some new properties are increasing their level of loft insulation to 300mm.
Choosing the right thickness for your insulation depends on various factors such as climate, location within your home, and type of material used. It's crucial to do thorough research, consult with professionals, and ensure proper installation for maximum efficiency.
25mm boards provide a good blend of price and effectiveness for insulating a shed on a budget.
Can I put plywood over insulation in the attic? Yes you can install plywood subflooring directly over the floor joists and insulation on your floor. You need to install rigid insulation boards on top of the attic flooring joists and then install plywood over the top.
Too much insulation will leave humidity and moisture to accumulate in your attic space. This can lead to mold growth on your walls and insulation. There might also be water damage to the support beams in your home's roof.
Also, when laying down additional insulation, work from the perimeter toward the attic opening. Never lay insulation over recessed light fixtures or soffit vents. Keep all insulation at least 3 inches away from recessed "can" lights, unless they are rated IC (Insulated Ceiling).
Boards for loft flooring can be installed on top of insulation using plywood, wood, or plastics. Installing loft flooring and boarding over insulation helps save space, prevent heat loss, and increase home value.
Do I Have To Remove Old Insulation? Unless your insulation is wet, moldy or infested with pests, you don't need to remove it before adding insulation on top of it. ENERGY STAR® recommends that you inspect your insulation for signs of mold, mildew, moisture and pest infiltration before making this determination.