Questions and answers for architects, builders and prospective owners of thatched properties

What is thatch?
Thatching means to cover a roof with material of a vegetable origin . The type of material chosen used to depend on its local availability.

How does thatch keep weather out?
A combination of its compactness and the steep pitch of a thatched roof, means water runs off the roof by dropping from one end of a stem of reed to another. A new thatch will only ever get wet about 1 inch down from the surface.

Why don't most thatch roofs have gutters?
Generally because of the thickness of the thatch the bottom projects far enough away from the walls of the property to shed the water away from the walls.

Can I have gutters?
Yes they lay on metal brackets and are generally made of timber and are V-shaped. Some people have them over doorways.

How thick is thatch?
Generally 12 – 15 inches thick.

Why are some roofs a lot thicker than this?
With straw roofs layers are added to existing layers, sometimes these roofs can be 3 or 4 inches thick.

Is it the case the thicker the thatch the better?
No, it is not the thickness of the thatch, but the pitch of the reed on the roof that is the crucial element in shedding water. Often a thick coat of thatch will have a slacker pitch. The length of the reed or straw also has a role to play.

How long does a thatch roof stay new looking?
About 2 years. Most then turn a charcoal grey colour.

How long does a thatch roof last?
It depends on the material, it depends on the pitch, it depends on the aspect of the roof, and it depends on the workmanship. Generally water reed is thought to last the longest around 40 - 50 years.

Will a roof require any maintenance?
A new ridge will need to be fitted every 10-15 years and at this time the whole roof can be dressed and cleaned and any moss removed.

Does a thatch roof attract mice, vermin, and spiders?
Any roof space will have spiders - thatched or not. Often if mice are in a thatched roof they too would be found in a non-thatched roof, especially in rural areas.

Does it catch fire easily?
Not easily. Shut the thickest book you can find and try lighting its closed pages on the opposite side to its spine! Lack of air and compactness is the key as with water shedding.

Can the materials be fire-retarded ?
Yes but not fire proofed! The material can either be sprayed on completion or the material dipped in a fire retardant before being applied to the roof.  Please contact us for details.

Can I have real fires?
Yes no problem. Chimney heights should be well above the highest point of the thatch. Chimneys should have a lining and be well cleaned. Heat sensors that are specifically for chimneys on thatch roofs can also be installed.

How is thatch fixed to a roof?
Nailed, tied or stitched/screwed and with a recoating job pegged to a base coat.

Can any roof be thatched?
Yes so long as it is steep enough - 45 degrees or more is ideal.

I have an existing roof that I want to strip of tile and have thatched. What special construction features should I be looking at?
Thatch is very flexible. Most roofs require very little alteration. Please contact us for details.

I have a roof that is not quite 45 degrees, how long will it last if it was thatched?
Difficult to say. Even on many steep thatched roofs of 50 degrees + there are areas which have a slacker pitch, such as tops of dormer windows. One would not expect these to last as long as the body of the roof.

What about lead work?
With the exception of box gutters and gullies, all lead work is dressed down on to the surface of thatch i.e. around chimneys. We can do this for you.

How much does thatch weigh?
7lbs per square foot.

How does a thatch roof compare to the cost of other roofs?
One must look at this over the lifetime of any roof and take into consideration all insurance costs, heating costs, down pipes and gutter costs and maintenance etc. Certainly more expensive than most other roofs.

How long will it take?
It depends on the size of his team, the size of the roof and how complicated it is.

Is there much mess?
On a re-thatch yes; also ceilings that abut the underside of rafters may gain hairline cracks in them. On a new thatch there is less dust and rubbish can be disposed of on a daily basis.

Is thatch a good insulator?
Yes, the adage cool in summer, warm in winter holds true.