What are Thatched Roofs

Before moving on to how to insulate a thatched roof, you need to get your facts straight, that is know a thing or two about thatched roofs, their types and characteristics. This is equally important due to the fact that the type of your roof will most likely determine the insulation method. Although it is not likely that you will opt for constructing a thatched roof, especially if you are living in a densely populated and urban area where your roof is under the influence of fire hazards, this is intended for all of you living in the countryside or having a nice cottage in the hills, where you can use all the advantages of this type of roof. Namely, since made of natural material, it is extremely ecological, but what is probably more important, unlike nowadays roofs, it has some insulation power itself meaning that your job in insulating thatched roof will most likely be much easier, since you will not need as much insulation as you would need for a tile roof construction, for example.

First things first, let's try to make some basic classifications. In order of determining which type of roof you have, you will just need to check the roof's covering and consider the following:

• Thatched roof covered with water reed is one option. Water reed straws are longer and not so flexible, falling down in a straight line, thus giving the roof a neater look.
• Another variation of the previous type of thatched roof is the one made combing water reed and sedge or straw to increase its flexibility, durability and ease the maintenance.
• Long straw thatched roof is covered with winter wheat and usually has cut eaves and rolled or cut verges.
• Combed wheat reed roofs are covered with combed long straw and have similar characteristics and somewhat different appearance that the ones using long straw.

Another classification important for thatched roof insulation is the one immanent not only to thatch roofs, but also other roof structures, thus can be applied in general. There are two basic types of roof structures – cold and warm ones. Having a "cold" roof basically means that you are insulating the floors below the roof, thus creating a protective envelope for your interior and leaving the roof space cold, which is usually the case if you do not have an attic space or you are just not using it, thus there is no need to keep it warm or cold, depending on the season. "Warm" roofs on the other hand are the ones that allow the space under the roof to be insulated as well, that is kept warm or cold and not cut off from the rest of the interior.

Where to Insulate?

Bearing in mind the previously explained classifications, you can insulate your thatched roof either from above or below the structure, if you want to create a warm roof. While insulating from above involves removing the thatch completely, that is not the case if you opt for adding insulation from below. This is why it is important to assess whether the thatch needs repair or removal anyway and make the decision accordingly. If you have chosen not to remove the roof covering, you can insulate the roof from below, which can be done by either by creating another ceiling with insulation installed under the top floor or by adding insulation between the roof rafters. However, be careful not to create cold bridges which can occur if there are any gaps between the material and the roof rafters.

Since thatched roofs are somewhat easier to maintain and much easier to replace than traditional roof coverings, you can decide to lift the thatch and insulate your thatched roof from above. In this case, the material is added above and between the rafters but can be done much more thorough with minimum risk of creating cold thermal bridges due to the fact that you will have better accessibility if you are adding insulation from above.

Now, let's consider cold roof structures. This includes insulating the top floor of your home that is creating a block between the roof space and the rest of the interior. This means that your roof and attic space will remain cold during the winter and hot during the summer but this will not anyhow affect the rest of your home, since it will be properly protected by insulation. Another good thing and possible advantage of thatched roofs is that they have greater insulation power than traditional roof structures meaning that the thatch itself will be just as good insulator, especially if the eaves are properly sealed.

Which Insulation Material to Go for?

Now that you are aware of thatched roof insulation basics, it is time to find the most suitable insulation material. What you need is a material that has good R value (due to the fact that roofs are under the direct influence of the weather conditions), that is easily maintained and shaped (since it needs to fit nicely between the rafters and fill all potential gaps and holes), which is a naturally grown material (in order of matching your thatched roof structure), that will allow the entire structure to breathe and take care of moisture problems which are a common occurrence in attic and roof spaces. Bearing in mind all the criteria set above the answer is simple and thus our advice would be to use sheep wool insulation for your thatched roof, as being a more eco-friendly insulation material than mineral wool, but maintaining the same insulation power. Depending on the dimensions of your roof and the position of the rafters, you can either opt for slabs or rolls, which are equally easy to cut to the right size and place in the right position, regardless of the insulation method.