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The Beauty of Timeless Thatch

Much of the world probably associates thatch with Africa, yet we don’t have a monopoly on it – in fact without thatch the Great fire London wouldn’t have been that great!

How can you explain the procedure of taking a humble piece of grass and make from it a practical piece of art, a thing of beauty and elegance?  How can you put a price on that?  Yet for those who live in the real world, thatch roofing does come with a price – today we may pay anything from less than or more than R1, 000 per square metre, completed.  Another way of looking at it is to say that thatching is perhaps as much as 60% higher than the price of conventional roofing.

There are those who may find low cost craftsmen to do their work, but these are becoming far and few as the vegetation needed to thatch is becoming sparser.  Where thatch was once the domain of those of lived off the land, thatch is today a choice of many affluent communities who hanker after a rustic look.

The Art of Thatching

Thatching is a craft, one that is, or was, traditionally passed down from father to son, each generation perfecting or improving the craft a little more.  Because of this “apprenticeship” method of thatching, not much has been documented about the craft which is unfortunate for many homeowners living in South Africa.

It is a labour intensive procedure and while perhaps one of the oldest building materials in history, our modern building practices use innovative methods for laying it down which gives a cleaner interior finish, leaving no hanging bits for insects to make their homes in.

Thatch as mentioned before is a natural material, a grass or more aptly, a reed.  In South Africa we use indigenous grasses which are readily available and eco friendly by their very nature.  However there are some types of grasses or reeds that will not do the job properly.  It is all about thickness. Thatch has to be of a certain thickness to be effective. It can also be either hollow or solid.

Thatching found in KZN for example has a finer texture than its counterpart found in Gauteng and is often preferred because of this quality.   However there are certain grades of thatching and Dekriet stalks used are purportedly of the best quality.  It is 3-4mm in diameter and is solid.  It is also one of the most expensive options.

Thatch has the ability to form lovely curved shapes and once aged, thatch blends in with its natural surroundings beautifully, especially here in South Africa.

Because of its beauty thatch allows for high open ceilings that give space and light and allow for cool breezes in hot climates, in fact that is an almost perfect natural insulator which keeps the interior cool in summer and warm in winter. 

Introduction to Thatch Design

A thatched roof should ideally have a pitch of about 45° minimum as this is one way of keeping the design cost effective.  The roof framing generally consists of chemically treated poles that are able to deal with its weight.  If you consider that a bundle of thatch 150mm thick weighs around 20-25 kilograms, it soon becomes quite a load to support.   Poles should be spaced up to 90cm apart, but many South Africa builders prefer a space of around 70cm with a pole diameter of around 100mm.

Different grasses are used for the finishing of the ridge capping as they are softer and more pliable, and easier to shape.  They also allow for the ridge capping to be trimmed into highly decorative profiles such as scallops or geometric shapes which give the roof a highly pleasing look while serving the role of keeping the entire roof watertight.

Down pipes and gutters are never used in thatched roofs, instead they are constructed with what are called “dripping eaves”.  It’s all about keeping the aesthetics in place.  These eaves overhang at least 65cm and provision must be given to those areas on the ground under these eaves in order to prevent soil erosion from the constant drips.

How Durable are Thatch Roofs?

Most thatch grasses will last around 25 years, others a little longer, such as Dekriet which offers a 35 years lifespan.  However, you should be aware that roof ridges will need to be replaced probably every 5 years or so.

Thatched homes gives us an ecological advantage, they harmonise with their surroundings, keep the temperature of our homes regulated and are a pleasure to live in even if they are maintenance intensive.

In the other hand, thatch is vulnerable to fire unless precautions are taken to minimise the risk.  Thatch is organic so it is also susceptible to decay, but there are precautions one can take to minimise this possibility.

How your thatch performs depends on its shape, how it is designed, the pitch of the roof and where it is placed.  Thatch by nature will absorb water and while on the one hand this is a great natural fire retardant, on the other hand you don’t want it to get water logged causing it to become heavier and increasing the likelihood of decay.  A pitch of around 50° will help prevent this.  If you have any large trees overhead, clear them away as constant brushing up against your roof will cause snagging which will pull out the reeds and lead to potential holes.

Fire Prevention

One of the most potentially devastating hazards for thatch is lightning and a lightning conductor that curtails to the SABS Code of Practice must be installed.  It may be possible to install a spike on a chimney or two masts instead of one gigantic one, but you should investigate this with your fire insurance first.

If you are installing a fireplace in your home make sure that it is constructed in a way that ensures that the outer faces coming into contact with the thatch do not become hot, usually all that is necessary is to use a double course or a 220mm full brick thickness in its construction.  Make sure that all the mortar joints are properly filled and that the top of the stack extends at least 1m above the highest point of the roof.

You will also need to educate yourself and your family, neighbours too if possible, on how you can reduce combustibility.  Learn about fire retardant chemicals for putting out fires, how to use fire resistant blankets to smother a fire and how to go about soaking your roof with water.