Squashing your insulation reduces its effectiveness by 50% Numerous studies on the topic have indicated that there's a huge number of Britons who don't understand why doing this is so problematic. Mineral wool type insulation (the most common loft insulation) needs to retain its full depth in order to work effectively.
Compression: If the loft insulation is compressed, it won't insulate as well as it should and you'll lose more heat. Moisture: If the loft insulation gets wet, it won't insulate as well and could result in mould forming which will damage the insulation.
What Happens If You Compress Blown-In Insulation? Like batts, compressing blown-in fiberglass insulation improves the R-value per square inch while diminishing the overall R-value. Also like fiberglass batts, some amount of compression is OK if the cavity is completely filled.
Comments Section Roof insulation should not be compressed. Unfortunately yes, you need to lift the boards and use stilts. If you're doing anything like this, you really need to get the insulation up to 270mm before considering boarding. It'll have a noticeable impact on your energy bills.
It's important to leave a ventilated air gap between the insulation and the boards to prevent condensation on the underside of the boards. Make sure you don't squash the mineral wool when you fit the boards on top, as this will reduce its insulation value.
In order for insulation to do its job, sufficient airflow to the outside surfaces is required. Good ventilation in your attic will allow the moisture to get out.
When it comes to insulation, it's generally recommended to leave a gap between the insulation material and any other surfaces, such as walls, ceilings, or roofs. This gap provides ventilation and prevents moisture buildup, which can lead to mould and other problems.
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.
One important thing to remember is that insulation should never be pushed right into the eaves because it will interfere with airflow.
It is strongly advised not to fit 270mm of mineral wool and squash it down with boarding or any other items, as this will reduce efficiency and be ineffective at insulating your home. Instead, place mineral wool between the joists and then fit rigid insulation boards across the joists, with floorboards on 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.
Compressing fiberglass provides more R-value per inch, but reduces the overall R-value. That means, compressing fiberglass batts is ok if the cavity is completely filled.
The short answer is yes. Our guide reveals five of the top areas to air seal before installing cost-effective insulation products such as fiberglass and mineral wool. Sealing these areas will help home builders meet code requirements for building an airtight, more energy-efficient house.
Unless it's been damaged, loft insulation should last for around 80 to 100 years. It often depends on the material though. For example, spray foam insulation can last up to 80 years, while foamboard and mineral wool insulation can last a whole century before it needs replacing.
Replacing older loft insulation can boost your property's thermal efficiency, leading to significant energy bill savings, reduced carbon footprint, and a temperature-regulated indoor environment.
You will want to bring up your attic up to R-38:
If your attic has 5-6″ of existing insulation, you'll want to install an R-19 to achieve a total of R-38.
Squashing Reduces Thermal Performance: Compressing insulation can decrease its ability to trap air and prevent heat from escaping. Studies have shown that squashing insulation from 270mm down to 100mm will reduce its performance by over 50% significantly affecting your home's energy efficiency.
Insulation shouldn't be laid over any electric cables. Where possible, clip them to the roof joists or gently lift them out of the way whilst you install, before laying them over the insulation when it's in position.
Yes, an air gap between the roof and insulation is needed, especially for traditional materials like fibreglass, mineral wool, and foil insulation.
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.
Many of us know what causes mould; when moisture is trapped in the rooms of you home. Sometimes, there is insufficient insulation in the walls, so mould grows. However, not many people realise that additional insulation isn't always the answer. In fact, too much insulation can be the secret cause of mould.
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.
What If My Dishwasher Has No Air Gap? Without a dishwasher air gap, contaminated water can flow back into the dishwasher. A dishwasher air gap prevents this from happening by ensuring that the water flows in one direction: out of the dishwasher and into the garbage disposal.
After the insulation is in place you will want to add a vapor retarder, sometimes called a vapor barrier, if you need one. Not every wall does. A vapor retarder is a material used to prevent water vapor from diffusing into the wall, ceiling or floor during the cold winter.
To maintain airflow, leave a space of 38 to 50 mm (1 1/2 to 2 in.) between the top of the insulation and the underside of the roof sheathing.