Chimney Inspections

Chimney inspections and fireplace inspections of South African homes and other buildings must be carried out in accordance with the South African National Building Regulations.   HouseCheck inspectors only check the observable elements for defects and compliance. HouseCheck does not check the internal parts of chimneys.

The National Building Regulations (SABS 0400.1990) state that a fireplace used for the burning of solid fuel (generally wood or coal) must have a hearth made of non-combustible material of adequate thickness.

The hearth must extend at least 500 mm in front of the grate or fire basket and at least 300 mm beyond each side of such grate or fire basket.  No timber floor joist or trimmer or any other combustible material shall be built into any hearth.

Flue pipes

A flue pipe is a metal tube (round or square) which either replaces the chimney or which is fitted inside the chimney.  No flue pipe shall be designed and installed in such a manner that it will cause a fire hazard to any adjacent material.   This means in practice that the flue pipe, which gets very hot, must not be close to combustible material such as wooden roof timbers or thatch.

Chimneys

A chimney must comply with the following requirements:

The chimney must be designed and erected with non-combustible materials and in such a manner that it will not cause a fire hazard to any adjacent material.

No combustible material, such as a timber floor joist, trimmer or roof truss shall be built within 200 mm of the inside of such a chimney.

The masonry walls of any chimney which are less than 190 mm thick must be lined (with a metal flue).  The minimum thickness of masonry chimney walls is 90 mm. The thickness of any chimney wall in any building covered by a combustible roof shall be not less than 190 mm.

Where any chimney is provided with a flue lining such lining shall be made of material which will withstand any action of the flue gases and resist, without cracking or softening, the temperatures to which it may be subjected and it shall extend throughout the full height of such chimney.

Where any chimney has either a laterally unsupported height greater than 4 m or a laterally unsupported height greater than six times its minimum lateral dimension it shall be designed by a Competent Person.

Generally speaking the height of any chimney outlet shall be not less than 1 m above the highest point of contact between such chimney and the roof.

The home inspector should also check the condition of the chimney masonry and the flashing (waterproofing) around the base of the chimney.

The top of a masonry chimney (the crown) should be waterproofed and sloped to facilitate water drainage and prevent water penetration into the chimney masonry..

If the chimney has been fitted with a cowl then the condition of the metal cowl should also be checked.

Proper evaluation by the home inspector, should determine if further investigation by a structural engineer or a fireplace and chimney specialist  is necessary.  When in doubt the home inspector should always recommend further evaluation by an appropriate specialist.

Recommendations  for effective repairs should only be made by the home inspector if this is within the scope and knowledge of the inspector.