So there you are, shopping for your dream home, including a pool and a lovely thatch roof Lapa to entertain your family and friends during our hot summer months. That lapa could turn out to become a bit of a nightmare though, as many home-owners know very little about the lapas they have around their swimming pools and in their gardens.
Obviously, the thatched roof is the most important part of the lapa because that keeps you dry! But did you know that thatch roofs should have a roof slope of 45˚ or more to perform properly? The steep slope is needed so that water will run off from the thatch with minimum penetration into the thatch. At a pitch of less than 45° the thatch will decay rapidly. Furthermore, the thatch will absorb the water increasing the weight on the support structure! Then of course there is also the thickness of the thatch to take into consideration. This is where many lapas have shortcomings! The thatch thickness should be at least 175mm and should be well compacted! Also, the thatch thickness should not be more than 250mm!
What is a “well compacted” thatch? When it is not easy to pull out individual stalks of grass, the thatch is normally considered to be well compacted.
Now we get to the structural issues that may crop up – For instance, the poles used as rafters should not have a diameter of less than 100mm at the thin end. In addition, the rafters should not be further than 900mm apart! The support poles should not be further than 3.5m apart. Support poles are the poles that go into the ground that holds the whole structure up. All the poles used to construct your lapa should be treated. The support poles in the ground are also specially treated to withstand insect and moisture damage. Special fire precaution is of the utmost importance as it may result in destruction of your and neighbouring buildings.
Insurers prescribe that the following measures be taken in order to protect a lapa against fire:
• In cases where a chimney penetrates the roof of any thatch structure, it should be constructed in such a way that the exterior that is in contact with the thatch cannot become hot. In normal chimneys a full brick thickness (220 mm) is necessary to satisfy this requirement.
• All mortar joints in the stack must be properly filled.
• Dress the area where the chimney stack penetrates the roof plane with sheet metal or fibreglass reinforced polyester flashing over and underneath the top surface as well as between the layers of the thatch. The width of the flashing should be at least 250mm.
• The chimney should be 1m higher than the thatch roof.
• A spark arrestor, fitted not less than 700mm from the top of the stack must be provided in all chimney stacks. The typical spark arrestor comprises of a 10 x 10 mm (minimum) section of stainless steel wire mesh across the full width of the flue and securely built into the flue around the edges or supported on mild steel dowels.
• Have the chimney flues cleaned at least once a year to avoid an accumulation of soot which can ignite or generate sparks.
• Keep an area of up to 25m around the lapa / thatch clear of unkept plants, grass and weeds to prevent fire hazards from sparks, etc. This condition however does not apply to cultivated and maintained lawns and gardens.
• Have fire fighting equipment ready on site. In compliance with the National Building Regulation 12, you are responsible for the testing and servicing of the equipment once a year to ensure that it would be ready for use at all times. In most cases a 4 kg dry powder fire extinguisher should be sufficient.
• It might be a good preventative measure to use treated grass for the thatch but it is not compulsory.
Although a lightning conductor is not compulsory, the insurer may insist on the installation of one, and it might be a good preventative measure, especially in Gauteng with its frequent thunder storms. According to the insurers, an effective lightning mast is of such a height as to provide a shielding angle to the structure/s it is meant to protect. A minimum angle of 45 degrees taken from the highest tip of the mast to ground zero is prescribed. The mast can either be attached to the building or free-standing and should furthermore be bonded to the earth electrode of the structure or an earth electrode of its own.
The metals that were used in the thatch construction (i.e. wire mesh, metal coated insulation, etc.) should also be bonded to the earth metal water main or earth electrode of the structure. If the chimney or gable ends extend above the shielding angle of the lightning mast, a peripheral conductor should be used around the chimney or along the gable. This should be connected to a down conductor bonded to the earth electrode or water main.
Further than the above, lightning conductors should be installed to protect thatched buildings or structures in accordance with the recommendations contained in SABS 03:1985. The installation of lightning protection should be undertaken only by qualified contractors. If you don’t have one get it done! Your insurance company will probably insist on one!
After all of the above points, your lapa may be still be illegal! If you have a lapa and it is not shown on any approved municipal drawings it may be an illegal construction. Check your approved drawings and do the right thing if it is not! Your insurance will not cover your lapa and it’s contents if this is not corrected!
All thatched roofs and lapas are required to comply with the SANS 10407: 2015 Edition 2 specification pertaining to thatch roof construction and SANS 10400 (National Building Regulations with special reference to part L). Your lapa must be built according to building plans designed and approved by a registered professional engineer. The formal approval must be clearly visible on the design drawings. The drawing must be signed by a competent person!
Many lapas are constructed close to or against boundary walls. South African building regulations stipulate that any thatch roof covering a roof-plan area greater than 20m² must be constructed at least 4.5m from any boundary. This is to prevent a fire from spreading to your neighbour. If a thatched lapa has been erected within 4.5m further steps must be taken to ensure adequate fire safety. Thatched lapas with a roof plan area of less than 20m² can be built up to 1m of the boundary. However, this is providing the lapa is a non-habitable structure (meaning that you don’t entertain or live in it). It must be free-standing and not attached to any other structure, either on your property or your neighbour’s.
So who actually inspects and certifies your Lapa then? A competent person (usually an engineer or similar) must certify that the construction complies with the SANS 10407 specification. He or she confirms that your lapa is built as designed and that the workmanship is of a professional standard. You will then receive an A19 Certificate of compliance confirming that the lapa complies with all standards and regulations. Without such a certificate the municipality will not sign off any structure for approval. The building inspector will also issue a Completion Certificate from the Municipality when all requirements have been met. No property may not be bought or sold without this certificate.
So, when buying a home make sure that you receive the approved plans for the property including the approval for the lapa. You are responsible for the process of having it approved if you are considering having one built on your property!
In conclusion: Try and ensure that the company or person erecting your lapa is registered with TASA (Thatchers Association of South Africa). Thatchers registered with TASA all comply with the requirements and standards of a quality thatched lapa. This will give you peace of mind and also protect your investment. Then you can truly enjoy your Lapa!