Consider using high-density R-30 blocks, which are as thick as R-25 blocks, but fit in 2x10 frames. You can also add rigid foam insulation under the beams, which adds R-value and eliminates the formation of thermal bridges through wooden beams. One of the most common and effective ways to insulate the ceiling is with spray polyurethane foam. This spray-applied plastic is known to be very effective in sealing any cracks, as well as in resisting wind and heat.
The foam is applied to the bottom of the roof covering and directly onto the slates and shingles. Then, spray foam insulation binds the slates and shingles together to prevent unwanted moisture, wind, heat, and cold air from leaking in. Requires the intervention of a contractor: while the installation seems fairly simple, spray foam insulation is comprised of strong chemicals that can cause respiratory, eye and skin problems without adequate protection. The vapors themselves are also highly flammable.
Foam blocks airflow, doesn't need vapor barriers, and has a higher R-value per inch than loose padding or blocks, so you'll get more protection with less depth. With spray foam, unlike loose filling or blocks, you must cover the ceiling vents (they are not necessary to keep the roof cool). Then cover the foam with drywall as needed to prevent fire. Insulation can be cut to fit around roof beams and beams, but it doesn't provide the same sealing as spray foam insulation.
It is completely prohibited to cover ceiling vents with loose padding or blocks, which can happen if insulation is placed along the eaves. Available in fiberglass or cellulose, this type of insulation is usually placed in hard-to-reach places, such as an unfinished roof or attic, through a long, flexible tube. The flow of air from the ceiling panels to the vent of the ridge keeps the roof cool and prevents ice from accumulating, and the material will block that flow. Well, now it's not covered by building regulations, but apparently, it's not your loft either or you wouldn't have this problem, so yes, insulate with that, it will stop the cold to a certain extent, but not as good as the Celotex or Kingspan 120mm thermal plate and, of course, rock wool is much cheaper.
Inside these hatches I have noticed, due to the wind and the cold, that there is no insulation at the bottom of my roof tiles. Whether you plan to install it yourself or hire a trusted roof insulation contractor, insulating your home will reduce your energy bills, reduce carbon emissions, and keep your home warm in winter and cool in summer. As outdoor temperatures continue to drop, insulating your roof is one of the most important ways to keep your home warm during the winter. The biggest advantage of installing insulation on your home's roof is the amount of money and energy you'll save.
However, if the floor is covered with plywood, not enough insulation can be placed underneath it to do enough of the job, even in hot weather. Before deciding whether to do the installation yourself or to hire an insulation contractor, remember to carefully examine the condition of your roof. Rigid insulation panels can be used virtually anywhere in the home, including roofs, basements, living spaces, and attics. With spray foam insulation, a polyurethane or latex spray is uniformly applied directly to the underside of the roof covering, slates and shingles.
You must leave a space in the back of the insulation between the membrane and the insulation to allow air to circulate through the roof space...