Loft insulation is designed to insulate the floor of the loft, and it involves laying insulation materials between the joists. Room in roof insulation, on the other hand, is designed to insulate the sloping walls and ceiling of a converted loft space, where the roof space has been turned into a habitable area.
The key difference is the positioning of the insulation. To insulate a loft used for storage, you'd need to insulate directly on top of the joists to the ceiling below. For room in roof insulation, you need to layer the insulation just underneath the roof.
Roof insulation provides whole-home temperature control and is ideal for homes with converted attics or complex roof structures. Attic insulation, on the other hand, offers a cost-effective solution, focusing warmth and energy efficiency on the main living spaces below.
Ceiling insulation usually refers to insulation that is installed between the ceiling rafters. Roof insulation means insulation that is installed under the roof materials.
Room in roof can make significant savings on your fuel bills, which will mean that it pays for itself in around 10 years through savings.
Excessively thick insulation can block most ventilation sources, reducing air quality and restricting air exchange within the loft.
One important thing to remember is that insulation should never be pushed right into the eaves because it will interfere with airflow. If you're going for a warm loft then you'll need much more insulation to be able to cover the underside of the roof along with the gable and party walls.
Roof and ceiling insulation. Installing roof and ceiling insulation can save up to 45% (or more) on heating and cooling costs.
Since insulation is not water-resistant, insulating your ceiling will give you better protection for your money. The insulation in your ceiling is less likely to suffer damage from unidentified leaks. When a roof leak develops, you'll find it more easily, which means you can have it repaired sooner.
Fiberglass batt is considered to be the best insulation for attics. Compared to other insulation materials, it is the cheapest and easiest to install.
Do you have any plans for furnishing/fitting out your attic in the future? Then you could simply insulate the pitched roof. But the best solution is actually to insulate both the attic floor and the underside of the roof.
In unfinished attic spaces, insulate between and over the floor joists to seal off living spaces below. If the air distribution is in the attic space, then consider insulating the rafters to move the distribution into the conditioned space.
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.
Should I remove old loft insulation before laying new? Older insulation material will typically need to be removed before adding new insulation. However, in some cases the material may be in good condition, meaning you can simply top up the existing insulation material for a fraction of the cost of a full replacement.
As stated in Approved Document L, loft insulation should be at least 270mm thick, which is the requirement for newly built properties. If you're looking to refresh the insulation in your loft space, you may find you have as little as 25mm, which was the recommended amount in the 1980s.
Sloping ceilings can be insulated in the same way as for a warm roof, but with a layer of plasterboard on the inside of the insulation. Vertical walls can be insulated in the same way. Flat ceilings can be insulated like a standard loft.
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.
The general advice we give is that you should always insulate between and above the rafters (warm roof) or between and under the rafters (cold 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).
As a general rule, insulation should be replaced or retrofitted every 15 to 20 years. However, it may need replacing or retrofitting sooner depending on the type of insulation installed, the R rating of the original insulation, compression and movement over time, and whether any damage has occurred.
The R-value for roof insulation and attic insulation should have a minimum value of 30.
Flat roof insulation cost
Flat roof insulation costs, on average, between £30 and £35 per square metre. The total cost depends on factors such as the type of insulation material, roof size, and the complexity of the installation.
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.
Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.
Realistically, the risk of over-insulating a loft is minimal. There's generally not enough space to install what would be considered too much insulation material. The depth of loft insulation in some new-build homes is being increased above the government-recommended 270mm to 300mm.