A thatched roof is an uncommon kind of roof seen most often on chocolate box cottages in English villages. The features of a thatched roof are the long straws of which it is made, and the fact that it’s often varnished.
But how thick is a thatched roof? The thickness of a regular thatched roof is usually between about 2 inches and 4 inches thick.
In many cases, a thatched roof is very old with lots of layers to it. This article aims to answer the question of how thick it should be and the different factors that affect the actual thickness of a thatched roof.
What Are The Layers Of A Thatched Roof?
Most often, a thatched roof is made from straw and some kind of insulation to prevent leaks. Which means there are two layers to it: the thatching itself, then underneath of this, a layer of insulation such as wood shavings, plastic or polystyrene or hessian sacking.
Wood shavings are a common insulation material for a thatched roof. It’s actually a very cheap and easy material to use – simply placed on top of the straw.
Another type of insulation used with a thatched roof is plastic or polystyrene. This is also cheap and easy to use as it can be laid directly onto the straw.
Hessian sacking is a less common form of insulation to have underneath a thatched roof. It’s much more expensive compared to using wood shavings. The sacking is lined up and put directly onto the straw through the top of the open tiles.
There are also various fire-retardant linings that one can use in this day and age.
Thatch Roof Thickness
Thatch roof thickness is usually between about 2 inches and 4 inches thick, depending on the type of straw. Long straws are the best to use, as they have a thicker thatch.
These straws can grow up to 4 feet tall!
Other factors that affect thickness include:
The weather
Weather conditions affect the thickness of thatch in different ways. It’s affected because it needs to be thicker when there is more rain, snow, or wind in order to stop water from getting through and damaging the home.
So generally, you would expect to find that roofs in very wet countries such as the UK, Eire, and Scandinavia have thicker roofs, while those in warmer areas with less rainfall have thinner ones.
However, these factors don’t only apply on a geographical level – some regions within a country vary wildly in rainfall amounts too!
For example, Norfolk on the east coast typically has a summer rainfall amount of between 40-60 inches per year compared to Yorkshire’s 25-45inches per year which makes Norfolk’s roofs thicker than Yorkshire’s.
Size
Another factor that affects thickness is the actual size of the house itself. A small dwelling with a small roof will not need as much material as a bigger one covering more roof space, for example.
Building Materials
The final factor that affects thickness is building materials used for other parts of the house such as tiles or slates – the presence of these will usually mean a thicker layer is necessary.
This makes sense because if you have an area where water has nowhere else to go but down and into the straw, it has to be thicker there.
How Is A Thatched Roof Made?
The process for making a thatched roof is not overly complicated. Generally, an English thatch roof is made in a four-step process.
Step 1
The straw itself is attached to a tough material called reeds which are used as small ties.
Step 2
The next step is strewing – this means sticking the straw or reeds down to the roof tiles with pegs or nails so it’s fastened securely in place.
Step 3
The next step is laying the straw over the ridge of the roof using more reeds held together by another kind of peg. This acts as another support for the thatch and helps spread it out evenly on top of the roof.
Step 4
The final step is covering it all up with an extra layer of insulation between two layers for water protection.
How Thick is a Thatch Roof?
To summarise, the typical English thatch roof thickness is between two inches and four inches thick.
The thickness varies depending on region, climate, soil, size of the house, and building materials used elsewhere on the house.
A thatched roof is made in 4 steps: attaching straw to reed, strewing it on with pegs or nails fastening it securely in place, putting more straw over the ridge using another type of peg that acts as support for the straw, then covering it up with an extra layer for water protection.
